R. Allen Waggoner, Kenichi Ueno, Josef Pfeuffer, Keiji Tanaka, Kang Cheng

Zoomed EPI with a transmit SENSE excitation was used to perform high-resolution fMRI of the human visual cortex at 3T. Tx acceleration was used to reduce the minimum TE by 6ms. BOLD responses were detected in the visual cortex with sub-millimeter in-plane resolution. A monocular stimulation paradigm was employed, and voxels displaying a left or right eye preference were detected, but ocular dominance columns were not apparent. These results show that using transmit SENSE at 3T with a 2-channel pTx system for high-resolution fMRI is possible, but would benefit from further steps to improve tSNR.

Manoj Shrestha, H. Sean Lee, Ulrike Nöth, Ralf Deichmann

An fMRI sequence for studying the auditory cortex is proposed, allowing for the insertion of silent delays of variable duration between EPI volumes during which auditory stimuli may be presented. Signal steady state conditions are maintained via spin saturation at fixed time points before each EPI volume. The method was successfully tested in vivo, yielding reliable activation of the primary auditory cortex. Results also show that high saturation efficiency is required to avoid erroneous activation patterns in compartments with long T₁ such as cerebrospinal fluid.

Jed Wingrove, Owen O'Daly, Fernando Zelaya

This work looks to see the effects of analysing and de-noising resting state functional data in the native space in comparison to the conventional methodology which utilises the normalistaion, by voxel interpolation and re-sampling, of images to a standard space. We sought to investigate these effects in rs-fMRI data collected in healthy volunteers and analysed with multi-echo ICA de-noising and seed based connectivity.

Junjie Wu, Shiyang Chen, Ganesh Chand, Kyle Pate, Amit Saindane, Deqiang Qiu

In this abstract, we evaluated dynamic functional connectivity (FC) using multi-band multi-echo EPI (M2-EPI) resting-state data, which has higher temporal resolution, less susceptibility related signal dropouts and better signal-to-noise ratio. Dynamic FC and its states can be observed using M2-EPI data. Reduced temporal variation in dynamic FC was found using M2-EPI data acquisition as compared to conventional single-shot EPI imaging. The use of M2-EPI BOLD imaging may help to better delineate the structure of resting-state functional networks.

Xiaoping Wu, Edward Auerbach, An Vu, Steen Moeller, Keith Jamison, Sebastian Schmitter, Pierre-Francois Van de Moortele, Essa Yacoub, Kamil Ugurbil

A major component of the Human Connectome Project (HCP) in the WU-Minn consortium is multiband-accelerated whole-brain resting-state functional MRI (rfMRI) at both 3T and 7T. Although providing better contrast and higher spatial resolutions, the 7T acquisition is compromised by RF nonuniformity. Here, we demonstrate the utility of RF parallel transmission (pTx) for 7T HCP-type rfMRI with 1.6-mm isotropic resolutions. Our results show that pTx can significantly enhance temporal SNR across the entire cortical surfaces and in many subcortical voxels relative to a CP-like-mode RF shimming mimicking single-transmit configurations, thereby holding great potential for acquiring high-quality, high-resolution and high-efficiency rfMRI data.

Zhiliang Wei, Jiadi Xu, Peiying Liu, Lin Chen, Wenbo Li, Peter van Zijl, Hanzhang Lu

Venous oxygenation level reflects the cerebral metabolic rate of oxygen and its measurement facilitates studies of animal models of diseases. We developed a non-invasive and non-contrast-agent method based on T2-Relaxation-Under-Spin-Tagging (TRUST) to quantify cerebral venous oxygenation in mice at 11.7T. A series of studies were performed to optimize key imaging parameters. This method may prove useful in studies of brain physiology and pathophysiology in animal models.

Myung-Ho In, Shinho Cho, Yunhong Shu, Hoon-Ki Min, Matthew Bernstein, Oliver Speck, Kendall Lee, Hang Joon Jo

Deep brain stimulation (DBS) fMRI has been considered as an emerging tool in investigating the DBS mechanisms and corresponding clinical outcomes, but suffers from severe susceptibility artifacts near metallic electrodes and tissue/air boundaries. A recent study showed that point spread function (PSF) mapping-based reverse gradient approach has a potential to correct distortions even in gradient-echo echo-planar imaging (GE-EPI) images with opposite phase-encoding polarity using a PSF dataset. To minimize the susceptibility artifacts, in this study, we apply the PSF approach for DBS-fMRI in swine. The results demonstrate that this approach can be beneficial for improving the reliability of DBS-fMRI.

Joonsung Lee, Hyun-Ji Shim, Hahnsung Kim, Jungryun Lee, Sangwoo Kim, Jeong Pyo Son, Won Beum Jung, Seong-Gi Kim

A single-shot variable flip angle (VFA) 3D GRASE imaging protocol was proposed for mouse somatosensory spin echo fMRI. Given echo-spacing of 24ms and echo train length of 8, 3D GRASE imaging parameters such as phase-encode schedule in partition direction and variable refocusing flip angles were designed to achieve pseudo-continuous signal modulation and effective TE of 40ms. BOLD fMRI experiments were performed using 9.4T MRI with ketamine anesthetized mice. For eight slice acquisition of electrical forepaw simulation fMRI, the proposed single-shot VFA 3D GRASE protocol achieved higher tSNR, t-values and larger activation areas than conventional 2D SE-EPI.

Patrick Liebig, Robin Heidemann, Bernhard Hensel, David Porter

We present an application of Variable-Blipped-EPI (VB-EPI) with readout-segmented EPI¹, which has possible benefits for functional Magnetic Resonance Imaging (fMRI) experiments. Acoustic noise is reduced by lowering the amplitude of the readout (RO) gradient, which is possible due to the RO segmentation, and by prolonging the duration of the phase encoding (PE) blips simultaneously. Even with standard Cartesian parallel imaging techniques, like Generalized Autocalibrating Partially Parallel Acquisitions (GRAPPA)², high resolution images can be obtained with high image quality.

Jeff Gunter, Joshua Trzasko, Bret Borowski, Clifford Jack,Jr.

Using only imaging data from an fMRI time series carotid cardiac cycle information may be automatically extracted.  By merging data across slices "faster than TR" sampling is achieved. The resulting time series agree with pulse oximetry (PO) data.  The distribution of relative peak times between PO and fMRI has standard deviation of around 40ms.  The fMRI data was quite reliable with cardiac signal observed for all but two of approximately 3000 seconds; PO data was much less reliable. 

Rita Nunes, Giulio Ferrazzi, Anthony Price, Jana Hutter, Andreia Gaspar, Mary Rutherford, Joseph Hajnal

The first fetal functional MRI studies used standard 2D multi-slice Echo Planar Imaging acquisitions, relying on post-processing for addressing motion-related effects. To reduce motion sensitivity, the use of Echo Volumar Imaging (EVI) combined with localized excitation has previously been proposed, but the very heterogeneous maternal environment renders selective excitation extremely challenging. We explored a more robust method combining EVI with inner volume imaging. By obtaining selective excitation from a spin-echo, sensitivity to field inhomogeneity is decreased, and spurious contributions from maternal tissue can be avoided. The method was tested in an adult and demonstrated in fetal imaging in utero.

Ileana Jelescu, Olivier Reynaud, Analina da Silva, Rolf Gruetter

Balanced SSFP (bSSFP) can be used as an alternative to gradient-echo (GE)-EPI for BOLD fMRI when image distortions and signal drop-outs are severe at high field. However, on animal systems, 3D-bSSFP acquisitions have low temporal resolution due to limited acceleration options and single slice offers insufficient coverage. Here, we perform multi-slice bSSFP in a pseudo-steady-state and show that non-distorted BOLD fMRI activation maps can be obtained, with comparable performance to GE-EPI. Future work will focus on resting-state fMRI using bSSFP and on the exploration of bSSFP BOLD contrast mechanisms at 14 Tesla.

Brice Fernandez, Laura Leuchs , Philipp Sämann , Michael Czisch, Victor Spoormaker

EPI suffers from signal loss in the ventromedial prefrontal cortex (vmPFC), a region of special interest in affective neuroscience. Last year, we showed that Multi-echo EPI (MEPI) was performing better than EPI in the vmPFC using a fear conditioning task. In the present work, we used a seed in the vmPFC, derived from the fear conditioning data, for a seed-based analysis on resting-state data collected from the same subjects. We demonstrate that the additional vmPFC cluster extent detected in the fear conditioning task reflects anatomically/functionally relevant activation as it is connected to bilateral amygdala and to the default mode network.

Denis Chaimow, Amir Shmuel

We show that the magnitude PSF fails to accurately represent the true effects of k-space sampling and signal decay. As an alternative, we propose to model fMRI with separate MR sampling and signal decay effects. We approximate the latter as a convolution with a Gaussian PSF or, if the effect is that of high-pass filtering, as reversing the effect of a convolution with a Gaussian PSF. At 7T signal decay in SE has a moderate blurring effect (FWHM = 0.89 voxels). Gradient-Echo acts as a high-pass filter, reversing blurring with FWHM = 0.59 voxels. 

Zhan Xu, Guangyu Chen, Shi-Jiang Li

Current Multi-Echo fMRI approach can only acquire up to three echoes due to the fast T2* decay. We hypothesized that more echo will improve the capability of increasing the BOLD CNR and denoise accuracy, and we managed to acquire up to six echoes using our within TR keyhole based approach: SCITH.  Our preliminary data showed increased BOLD CNR and resting-state functional connectivity(FC), less temporal FC fluctuation and more consistent inter-subject FC in the same population.

Pedro Lima Cardoso, Barbara Dymerska, Beáta Bachratá, Florian Ph.S. Fischmeister, Nina Mahr, Eva Matt, Siegfried Trattnig, Roland Beisteiner, Simon Daniel Robinson

The clinical relevance of correcting susceptibility-related distortions using a recently-developed dynamic distortion correction (DDC) approach is assessed. This was applied in fMRI data acquired from a group of 12 patients with a range of neuropathologies at 7 T. Despite the presence of pathologies, time series of artifact-free field maps were generated. If distortion correction was neglected, substantial displacements, both in EPI geometry and activation, were observed. Two cases with potential clinical implications were identified. The DDC was able to accurately correct distortions in all cases and is shown to be effective and clinically relevant in presurgical planning at 7 T.

Pu-Yeh Wu, Ying-Hua Chu, Jo-Fu Lin, Shang-Yueh Tsai, Wen-Jui Kuo, Fa-Hsuan Lin

By using a dedicated 24-channel temporal lobe array and surface based laminar depth analysis, we revealed the tonotopic representations in the human primary auditory cortex on a 3T MRI system. We found that, compared to deep and superficial layers, the minimal inter-subject variability of the tonotopic representation and frequency tuning width were found at the middle layer. Locations in the auditory cortex with finer frequency tuning had smaller inter-subject variability. Taken together, our findings suggested that middle layer of the auditory cortex has more specific frequency preference and selectivity, consistent with neurophysiological animal studies.

Guoxiang Liu, Takashi Ueguchi

We proposed a new segmented EPI reconstruction method based on physiological information to reduce influence of physiological noise. A human brain was scanned on a 7T MRI scanner using segmented EPI, while recording cardiac pulse and respiration data. Our results showed that the proposed reconstruction method can reduce the respiratory-related and cardiac-related signal changes in fMRI studies.

Georges Hankov, Giovanna Ielacqua, Basil Künnecke, Thomas Mueggler, Markus von Kienlin, Markus Rudin

In the past years, functional MRI studies in rodents have become more frequent. The signal losses in gradient-echo EPI due to the increased sensitivity to magnetic susceptibility differences at higher magnetic field, however, make fMRI studies of deep brain structures difficult. Here we propose the use of Poloxamer, a non-toxic amphiphilic triblock copolymer well known for its thermo-reversible properties and pharmaceutical application to fill up the air cavities in the rodent middle and external ear canals. This practical method considerably increases geometric fidelity of the functional images, opening up the possibility to longitudinally investigate rodent’s deep brain networks.

E Daniel Gomez, Zahra Fazal, José Marques, Thomas Beck, Benedikt Poser, David Norris

In the current abstract we explore the applications of Multiband Echo-SHifted (MESH) EPI as a potential tool for fMRI at 3T. We compare MESH and SMS-EPI in two sets of experiments: the first looking into typical fMRI protocols, and the second with a focus in BOLD contrast and temporal resolution optimization. We conclude that MESH can increase the temporal efficiency of fMRI and be used to reduce distortions without sacrificing BOLD contrast.

Prantik Kundu, Joao Correia, Saadi Ghatan, Daniel Samber, Michael Herbst, Benedikt Poser

The functional localization of language and other clinically relevant brain networks at the subject-level has been limited by fMRI artifacts such as head motion. These artifacts have forced task-based fMRI for functional localization to be designed around strict timing and strong constraints, such as silent reading in 20-second task-rest blocks. Such limits make experiments hard to follow by patients and not ecologically valid. Dealing with these artifacts, especially at patient level, has been challenging with standard fMRI methods. Here we combine the acquisition technologies of multi-echo fMRI, multi-band acceleration, camera-based prospective motion correction, and 7T MRI, to image canonical language and other networks during overt speech with 7T MRI using stimuli with complex language content with naturalistic timing.

Catarina Rua, Myung-Ho In, Renat Yakupov, Hendrik Mattern, Mauro Costagli, Mark Symms, Alberto Del Guerra, Michela Tosetti, Oliver Speck

Distortion correction is an essential step for anatomically faithful analysis of ultra-high-field fMRI data due to strong susceptibility-induced geometric distortions in echo-planar imaging (EPI). Although the point-spread-function (PSF) method allows accurate unwarping and increase in SNR, its effectiveness in modulating the undistorted BOLD signal is still unknown. In this study we applied the PSF-based distortion correction using different types of correction kernels to GRE- and SE-EPI data at different resolutions and directly to the BOLD contrast maps, and evaluated the effectiveness by assessing functional contrast, specificity, and false-positive-rate. 

Georges Hankov, Basil Künnecke, Markus Rudin, Markus von Kienlin

With the increasing need for translational readouts, the number of fMRI studies in rodents has grown exponentially in the recent years. Nonetheless, methodological questions regarding fMRI data acquisition in small animals yet have been poorly addressed. In this work, we evaluate the use of the PRESTO sequence for fMRI in rodents: a 3D alternative to EPI using echo-shifting and echo-trains minimizing distortions and artefacts related to the higher magnetic fields, while providing better brain coverage and faster temporal resolution, allowing appropriate physiological noise sampling.

Tae Kim, Yoojin Lee, Tiejun Zhao, Hoby Hetherington, Jullie Pan

B₀ shimming is important for gradient echo functional MRI where T₂^* signal loss and precession occur from both physiological and non-physiological susceptibility effects. We used the high degree shim insert (3^rd, 4^th and two 5^th degree shims) to assess its effect for 2mm isotropic whole brain GE-EPI BOLD (breath-hold induced) signal at 7T. Comparing 1^st-2^nd with high degree shimming, the Δ|B₀| changes are spatially varying. For activation, the largest regions of increase are in the inferior frontal region; the largest regions of decrease are in the middle temporal lobe. Overall, there is a 4.3% increase in total activated pixels.

Ying-Hua Chu, Jo-Fu Lotus Lin, Pu-Yeh Wu, Kevin W.-K. Tsai, Yi-Tien Li, Yi-Cheng Hsu, Shang-Yueh Tsai, Wen-Jui Kuo, Fa-Hsuan Lin

By asking subjects engaging a decision task of two levels of difficulty based on foveal stimuli, we measured the BOLD dynamics elicited by checkerboard flashing shown at the peripheral visual fields with two levels of attention using high precision simultaneous-multi-slice inverse imaging (SMS-InI TR = 0.1 s; 5 mm isotropic resolution). Results shown insignificant difference in the amplitude of the BOLD response by two tasks, while time characteristics of onset, time-to-half, and width differ significantly between tasks in the range of hundreds of milliseconds. 

Yoshifumi Abe, Khieu Van Nguyen, Tomokazu Tsurugizawa, Luisa Ciobanu, Denis Le Bihan

Diffusion fMRI (DfMRI) allows to monitor brain function without BOLD vascular confounding effects. To elucidate the origin of the DfMRI response we performed DfMRI experiments at single neuron and ganglia level upon dopamine stimulation of Aplysia californica buccal ganglia using 17.2T MR microscopy. Neural swelling, evidenced from optical microscopy, resulted in an intracellular ADC increase reflecting cytoplasm dilution and an ADC decrease at ganglia level. While the mechanism of this ADC decrease remains putative these results are consistent with the hypothesis that the ADC decrease observed with DfMRI upon neuronal activation at tissue level reflects activation induced cell swelling.

Leonardo Greco, Olivier Reynaud

To date, the White Matter (WM) tracts functionality is never directly assessed using fMRI, but only inferred indirectly via healthy/impaired cortical connectivity. In this study, we use Arterial Spin Labeling (ASL), a non-invasive, quantitative, reproducible fMRI technique, to investigate WM Cerebral Blood Flow (CBF) dynamics at high field. We first show that WM CBF can be measured using standard 2D-EPI-PASL at 7T; and quantify CBF changes in GM and WM during finger-tapping. While the BOLD signal was only found elevated in GM, a net CBF increase was observed in GM and contralateral (but not ipsilateral) WM during the task (+77/25%).

SoHyun Han, JinYong Park, Woochul Jeong, Seong-Gi Kim

In general, gradient-echo (GE) BOLD contains extravascular (EV) contributions from all sized vessels, while spin-echo (SE) BOLD is sensitive to microvessels. Based on simulation, the EV BOLD signal is dependent linearly on B₀ for macrovessels, and quadratically on B₀ for microvessels. Here, we performed GE and SE BOLD fMRI of α-chloralose anesthetized rats responding to forepaw stimulation on an ultrahigh magnetic field of 15.2T. Stimulation-induced R₂ change was quadratically on B₀, indicating that microvessel contributions are dominant. SE BOLD at ultrahigh fields can detect precise activation sites and can be used for high-resolution fMRI to detect fine functional structures.

Jonathan Polimeni, Natalia Zaretskaya, Johannes Stelzer, Jonas Bause, Philipp Ehses, Lawrence Wald, Klaus Scheffler

Several strategies have been proposed for maximizing neuronal specificity of fMRI by utilizing pulse sequences that are primarily sensitive to signal changes within microvasculature. Here we compare the microvascular sensitivity of high-resolution balanced SSFP and gradient-echo EPI at 9.4T using cortical depth analyses within human visual cortex. Because of the large draining vessels lying along the pial surface, the behavior of fMRI signals as a function of cortical depth can provide helpful insights into the vascular contributions. Our preliminary analyses suggest that, for the protocols used here, both balanced SSFP and EPI show similar cortical depth profiles of BOLD responses. 

Yusen Feng, Yingying Ding, Ya Zhang, Chengde Liao, Yan Jin, Peng Cao

In this article,to prospectively investigate the changes of quantitative parameters in dynamic contrast-enhanced MRI (DCE-MRI) and the apparent diffusion coefficient (ADC) of diffusion weighted imaging (DWI) in cervical cancer patients before and after neoadjuvant chemotherapy (NACT).It showed that quantitative parameters of DCE-MRI and ADC provided a new noninvasive way to reflect the changes of hemodynamics and water molecular diffusion in cervical cancer patients with NACT.

Yi-Tien Li, Jo-Fu Lin, Pu-Yeh Wu, Kevin Tsai, Fa-Hsuan Lin

We correlated between the temporal chacteristics of the BOLD signals and venule structure at human primary visual cortex (V1). Functional MRI was measured by the high temporal resolution (100ms) simultaneous-multi-slice inverse imaging.  Venule probability map was estimated from high spatial resolution (0.85mm) susceptibility-weighted imaging (SWI). Siginficant correlation was found between venule density and intra-/inter-subject temporal variability of the BOLD signal at V1. This correlation suggests that the temporal instability of BOLD signal is likely attributed to vascular structure or reactivity. 

shuangshuang xie, qing li, zhizheng zhuo, yue cheng, wen shen

This study evaluated the effect of Gd-EOB-DTPA on fat quantification using a multiecho reconstruction technique with T2* correction. Forty-six patients with suspected hepatic tumors underwent Gd-EOB-DTPA enhanced MR imaging and single breath hold 3D mDIXON-Quant for hepatic fat quantification before and 20 minutes after the administration of Gd-EOB-DTPA. Fat fraction (FF) and R2* of the liver parenchyma, spleen parenchyma and vertebral body were measured and compared between pre- and post-contrast. FF measurements of liver, spleen, vertebral body and R2* measurements of liver, spleen revealed no significant difference between the two measurements, and R2* increased in liver and vertebral body significantly after 20 minutes of Gd-EOB-DTPA administration. In addition, good agreement of FF measurement was seen in the Bland-Altman plots. We conclude mDXION-Quant can obtain stable fat quantification in the hepatobiliary phase, without the impact of an increased R2* in liver parenchyma. But R2* maps should be obtained prior to Gd-EOB-DTPA administration.

Jo-Fu Lotus Lin, Ying-Hua Chu, Yi-Cheng Hsu, Fa-Hsuan Lin

We used simultaneous-multi-slice inverse imaging to characterize the relative latency and temporal variability of BOLD signals in the human ventral visual pathway with 0.1 s precision. The intra-subject and inter-subject variability were 0.39 (s) +/- 0.49 (s) and 0.51 (s) +/- 0.77 (s) when images of faces were presented. When scrambled faces were shown, the intra-subject and inter-subject variability were 0.42 (s) +/- 0.46 (s) and 0.56 (s) +/- 0.74 (s). With higher temporal resolutions, we showed temporal variability of HRF vary across cortical areas. Within the same cortical area, the temporal variability of HRF differ between different visual stimulations.

Rosa Sanchez Panchuelo, Robert Turner, Susan Francis

We combined Arterial Spin Labelling (ASL) and Vascular Space Occupancy (VASO) techniques into a double acquisition FAIR sequence with double echo readout to provide simultaneous measures of arterial Cerebral Blood Volume (aCBV), total CBV and BOLD signals. Using this technique at 7T, we successfully detected aCBV and total CBV (and BOLD) changes induced by both a motor task and a vibrotactile sensory stimulation paradigm, and show that activation maps derived with the independent  ASL and VASO techniques largely overlap. 

Sean Foxley, Xiaodong Guo, Gregory Karczmar

Functional data were acquired of a finger tapping experiment using a conventional EPI approach as well as using high spectral and spatial resolution water spectra acquired using EPSI at 3T. Activation maps of both acquisition strategies were produced and compared. Expected task dependent areas of activation were seen in both, however, activation volumes were smaller in EPSI data. This could indicate that different Fourier components of the water spectrum are differentially affected by the BOLD effect. If this is the case, detailed analyses of the water spectrum could contribute to our understanding of the relationship between cognitive processes and the hemodynamic response.

Vahid Malekian, Abbas Moghaddam, Mahdi Khajehim, David Norris

T2-weighted fMRI methods including Spin-Echo (SE) and balanced SSFP (bSSFP), became of particular interest to reach superior functional specificity in high field application. However, both techniques suffer from a number of practical limitations. SE fMRI may be SAR limited at high fields. On the other hand, bSSFP suffers from dark bands. To eliminate dark bands in bSSFP, non-balanced-SSFP (nbSSFP) fMRI was previously suggested. Here, we developed a robust version of nbSSFP by using a single SSFP-echo sequence to decrease motion effects. The performance of the suggested sequence is evaluated and the results obtained are compared with bSSFP and SE-EPI fMRI.

Banafshe Shafiei Zargar, Farzaneh Keyvanfard, Abbas Moghaddam

Recently there has been growing interests in radial fMRI. However, the reconstruction algorithm is also an important issue in K-space radial sampling. In this work, we have investigated the effect of a novel reconstruction method based on polar Fourier transform, for radially acquired fMRI data in polar coordinates. Based on its special features such as central focusing behavior, the obtained results demonstrate the capability of this method in reliable activity detection in targeted regions and also show a higher temporal stability in those areas.

Ying Li, Rui Li , Wenjia Liu, Xin Lou, Lin Ma

In this crossover intra-individual comparison study, we aimed to compare the non-ionic (godadiamide, Gd-DTPA-BMA) and ionic (gadopentetate dimeglumine, Gd-DTPA) Gadolinium based contrast agents (GBCA) in the quantitative evaluation of C6 glioma with dynamic contrast enhanced MR imaging (DCE-MRI) at 3.0 T MR scanner. K^trans, V_e and V_P maps were generated. Three radiologists independently performed tumor segmentation and value calculation. Gd-DTPA-BMA has significant more pixel counts of glioma in K^trans map and increased tendency for average K^trans and K_ep values, indicating that DCE-MRI with Gd-DTPA-BMA may be more suitable and sensitive for the evaluation of glioma.

Kenneth Wengler, Andrea He, Hoi-Chung Leung, Xiang He, Chuan Huang

While the existing BOLD signal model often use a single-compartmental, empirical relationship among fMRI response, blood flow and neural metabolic demand, some model parameters can only be determined from calibration challenges. In this study, for the first time, the role of intravascular blood motion on BOLD response is evaluated by Monte-Carlo simulation. Combined with an analytical description of extravascular contribution, a unified BOLD signal model without the need for calibration can be established, enabling the quantification of neurovascular coupling efficiency in both goal directed and spontaneous neuronal activations.

Cristina Chavarrias, Guilherme Freches, Noam Shemesh

Diffusion fMRI (dfMRI) is highly promising for improving the detection of active regions with higher spatial accuracy, as well as for its potential of resolving faster dynamics than its BOLD counterpart. To test this hypothesis, we compared BOLD and dfMRI in the auditory pathway of the mouse, which exhibits clear tonotopy in electrophysiology. Our findings suggest that dfMRI activation maps are more localized and are in agreement with the expected area of activation in the inferior colliculus; dfMRI signals were also ~3s faster than BOLD signals. These results are expected to enable brainwide characterization of auditory reorganization, function, and plasticity.

Bowen Fan, Lirong Yan, Kay Jann, Mayank Jog, Ying Kui, Danny Wang

The brain pulsatility plays an important role in various cerebral pathology, such as brain tumor and traumatic brain injury. Two MRI methods have been recently developed for assessing brain biomechanical features using a ECG-gated cine sequence with different processing strategies. In this study, we evaluated and compared the two methods. Consistent findings were obtained using both methods that the majority of cardiac-induced brain pulsatile motion occurs in the brain stem and basal ganglia as well as in big arteries.

Lifang Wu

The purpose of this study was to explore the threshold of IVIM parameters,ADCtotal and ADC(0,500)  ratios 24-48 hours after TACE to assess early response  in patients with unresectable HCC and to compare the association between diffusion-weighted imaging with the IVIM-DWI and mRECIST with survival. Our study show that the ADCtotal ratio and D ratio 24-48 hours after TACE were independent predictors for response to TACE for HCC, and showed stronger association with PFS than mRECIST.

Matthew Cherukara, Alan Stone, Davide Carone, Radim Licenik, George Harston, James Kennedy, Michael Chappell, Nicholas Blockley

Streamlined Quantitative-BOLD provides a method for quantifying brain oxygen metabolism, in particular, deoxygenated blood volume and oxygen extraction fraction, based on linear fitting of values obtained from an asymmetric spin-echo sequence. It is possible that a curve-fitting approach may yield more robust values for these parameters. This study investigated the feasibility of estimating brain metabolic and vascular parameters through a Bayesian framework, through simulations, and analysis of patient data. It was found that under the current model, simultaneous estimation of oxygen extraction fraction and blood volume was not reliable, suggesting a limit to the model or acquisition protocol. 

Shuai Mao, Changle Zhang, Heather Ma, Na Gao, Yanwu Yang, Yan Wang

Based on resting-state fmri (rs-fMRI) data, this study aims to investigate the method of identifying AD and normal controls through the procedure of feature extraction and pattern recognition. We extracted the ALFF and ReHo parameters based on pre-processed resting-state fMRI data, and calculated some key parameters in graph theory through the functional connectivity network. Then the examination of the reliability of those features shows a satisfactory recognition rate of 94.4% to distinguish AD and normal controls.

Klaus Scheffler, David Kleinfeld, Philbert Tsai, Mario Báez-Yánez, Philipp Ehses

The neurovascular fingerprint of BOLD (blood oxygen level dependent) bSSFP (balanced steady-state free precession) is analyzed by Monte Carlo simulations for different vessel geometries and on a vectorized vessel data set of mouse parietal cortex. The results support that bSSFP yields vascular properties similar to those found with spin echo BOLD, a small intravascular signal contribution except for larger vessels, and a high selectivity to microvessels.

Laurentius Huber , Jun Hua , Valentin Kemper, Sean Marrett, Benedikt Poser, Peter Bandettini

fMRI at ultra-high field strengths (≥7T) allow submillimeter voxels across different cortical layers. A big challenge to infer layer-dependent activity information, however, is to find an fMRI contrast that has the best combination of local specificity to microvascular responses within cortical layers and sensitivity to detect activity changes. Here we compare contrast mechanisms that have been proposed to be applicable to layer-dependent fMRI, including blood volume fMRI with VASO, SE-BOLD, T2/T1ρ-prep-BOLD, diffusion weighted T2-prep-BOLD. We find that CBV-weighted VASO and T2-prep methods have a favorable compromise between sensitivity and specificity. Hence, we believe that these fMRI methods might be better suited for layer-dependent applications than conventionally used GE-BOLD and SE-EPI.

Jacco de Zwart, Peter van Gelderen, Matthew Schindler, Pascal Sati, Jiaen Liu, Daniel Reich, Jeff Duyn

Ferumoxytol is a blood-pool-bound superparamagnetic iron-oxide particle (SPIO) that has been shown to yield CBV-dominated fMRI contrast in humans. Differences in impulse-response (IR) timing were previously demonstrated in animals when comparing SPIO-fMRI to BOLD-fMRI. Since BOLD IR is known to differ between humans and animals, we aimed to repeat this SPIO-fMRI to BOLD-fMRI comparison in humans. SPIO-fMRI was performed in human visual cortex and IR was compared to BOLD data from the same subjects. Shorter stimulus onset time and time-to-peak were found. Stimulus design minimized neuronal interaction effects between stimuli; residual inter-stimulus interaction effects, presumably vascular in origin, were found to be minor in SPIO-fMRI, on the same scale as in BOLD.

Mario Báez-Yánez, Philipp Ehses, Klaus Scheffler

The phase accumulation that spins experience during a MR sequence is closely linked to the microstructure within the voxel, and basically produces changes in T2* or T2. The present abstract demonstrates how the static bSSFP signal profile is modified by the influence of local susceptibility differences produce by the underlying local-frequency distribution and diffusion effects related to white matter and gray matter at 9.4T. We apply an analytical presentation of the diffusion-modified frequency distribution, previously only used for gradient and spin echoes, to bSSFP and we prove the applicability of this theory to bSSFP by Monte Carlo simulations and measurements.

Chao Zhang, Kuncheng Li, Nan Chen, Hongyu Yang

This study aimed to observe dynamic functional organization changes of large-scale resting state network (RSN) in MTLE and the patient who got seizure free after surgical treatment. Subject specific RSNs of three groups (healthy controls, presurgical group and posttreatment group) were extracted using group-information guided independent component analysis. Then, we calculated and compared the FC results between three groups, and we found FC altered markedly before and after surgical treatment. In addition, there was no statistical difference between posttreatment group and healthy controls. Our results may provide valuable information for further understanding of the pathophysiological mechanisms of intractable MTLE.

Ye Xie, Jian Weng, Chunjie Wang, Feiyan Chen

Cognitive training is an interesting topic in Neuroscience. Abacus-mental based calculation (AMC) training improves math ability that indicates it might affect functional connectivity architecture. Modularity analysis showed between-group differences in visual network and cingulo-opercular network (CON). Compared to the controls, increased local efficient observed in visual network, while decreased in CON in AMC experts. An alternative reason is that visual-spatial strategy involving in AMC training rather than languish strategy, leading to different trend to networks related to different function. Our findings shed light on topological reorganization of functional connectivity induced by AMC training.

Wahaj Patel, Alexey Dimov, Yi Wang, Yihang Yao, Brian Kopell, Rafael O’Halloran

The relationship between iron concentration, evaluated via quantitative susceptibility mapping (QSM) and white matter connectivity, assessed with 3T MRI, was explored. Such a relationship might be useful in deep brain stimulation (DBS) surgical planning, where both QSM and white matter connectivity are gaining interest. For several relevant regions of interest in movement disorders such as the superior frontal, pre central and post central gyrus there was a strong correlation between STN connectivity and QSM intensity. To allow quick assessment of the spatial variation of connectivity in the STN, an RGB image was computed from connectivity in 3 regions of interest. 

Ying Wang, Junjing Wang, Yanbin Jia, Tao Liu, Yao Sun, Shuming Zhong, Zhongping Zhang, Li Huang, Ruiwang Huang

Our findings suggest that bipolar disorder (BD) and major depressive disorder (MDD) may have some shared and morespecific impairments of functional connectivity patterns during the depressiveperiod, providing new evidence for pathophysiology of BD and MDD at thelarge-scale whole brain connectivity level.

Yao-Chia Shih, Chang-Le Chen, Shih-Chin Fang, Tzung-Kuen Wen, Da-Lun Tang, Si-Chen Lee, Wen-Yih Tseng

Mindfulness-based stress reduction (MBSR) has been known to improve emotion regulation and cure mood disorders. The present longitudinal study aimed to clarify the effects of MBSR training and practice on the neural substrates of emotion regulation. Resting-state functional MRI (rsfMRI) exams were performed at three time points to investigate changes of functional connectivity (FC) within the subgenual anterior cingulate cortex (sgACC) network. MBSR training and practice strengthened the FC of sgACC with the inferior frontal gyrus and with the insula, and reduced the level of anxiety and depression. The findings reveal the neural substrates of emotion regulation process following MBSR.

Yu-Chen Chen, Wenqing Xia, Xindao Yin

Our results identified disrupted effective connectivity networks in the limbic regions of tinnitus patients. Tinnitus severity was positively correlated with a bilateral increase in effective connectivity from the amygdala to the auditory cortex on the same side. In addition, tinnitus duration was positively correlated with enhanced effective connectivity from the right hippocampus to the left auditory cortex. These findings mainly emphasized the crucial role of limbic system and limbic-auditory interaction in tinnitus patients, which could help enhance our understanding of the neuropathological mechanisms underlying tinnitus.   

Tun-Wei Hsu, Jy-Kang Liou, Chien-Yuan Lin, Ralph Noeske, Jiing-Feng Liring

In this study, we combined resting-state functional magnetic resonance imaging (rsfMRI) and advanced magnetic resonance spectroscopy technique to demonstrate a positive relationship between levels of inhibitory neurotransmitter gamma-aminobutyric acid (GABA) within posterior cingulate cortex/precuneus (PCC/PCu) and high network centrality of primary network. High network centrality propagates and contributes to efficient information flow in brain network. The PCC/PCu is a key component of default mode network (DMN) and high regional GABA levels expressing in the PCC/PCu area deactivate DMN activities related to internal thoughts for reallocating attention resources from internal processes to goal directed external stimuli with high network centrality.

Tommaso Gili, Valentina Ciullo, Daniela Vecchio, Gianfranco Spalletta, Federica Piras

Sense of agency (SoA) refers to the experience of controlling one’s own actions. Temporal distortions between the action and the effect mislead agency attribution. We investigated the covariance between the amount of functional interactions among brain regions at rest and SoA. We found that the functional network involved in self-agency attribution included the premotor and somatosensory cortices bilaterally, and the right superior parietal lobule. This provides the first evidence that functional connectivity at rest in healthy subjects varies along with experienced SoA, implying that self-agency is processed within an intrinsic brain functional module.

Debby Klooster, Rene Besseling, Suzanne Franklin, Antoine Bernas, Romain Duprat, Albert Aldenkamp, Chris Baeken

The effect of accelerated intermittent theta burst stimulation (aiTBS) is investigated in three resting-state networks involved in depression: default mode network (DMN), central executive network (CEN), and salience network (SN). Multivariate Granger causality analysis was performed between time-series representing each network and between time-series of nodes belonging to these networks. The effects of the latter analysis were quantified by the in- and out-degree. No between-network effects were found but specific connections showed increased or decreased Granger causality after stimulation. Clinical responders showed changes in the in- and out-degree of the anterior cingulate, known to be important in depression pathology. 

Fei Gao, Guangbin Wang, Bin Zhao, Fuxin Ren, Weibo Chen

This study revealed abnormal resting-state functional connectivity between the Heschl’s gyrus and distributed regions located in the hearing-related and language-related areas in patients with presbycusis. Our findings could be important for exploring imaging evidence of central component of presbycusis.  

Jacky Tai-Yu Lu, Claire Hui-Chuan Chang, Shu-Yu Huang, Wen-Jui Kuo, Fa-Hsuan Lin

This study used functional magnetic resonance imaging (fMRI) hyperscanning to estimate the synchronization of human brain activations in interpersonal interaction by inter-subject correlation (ISC) analysis. Brain activations of pairs of subjects were recorded simultaneously during real-time video tennis game under cooperation, competition, and a control condition involving no interaction. Compared to control condition, higher ISC was found in premotor area (BA6) and right precuneus in the two game conditions. The finding of premotor area suggests that mutual action understanding was supported by the mirror neuron system during interpersonal interaction.

Tommaso Gili, Rossana Mastrandrea, Andrea Gabrielli, Fabrizio Piras, Gianfranco Spalletta, Guido Caldarelli

The intrinsic functional architecture of the brain and its alterations due to cognitive engagement, ageing and diseases are nodal topics in neuroscience, attracting considerable attention from many disciplines of scientific investigation. Complex network theory offers powerful tools to investigate brain connectivity disclosing the structure of the human brain functional network. Here we put forward a number of methods to investigate the network of brain areas coupled by their functional coordination without introducing exogenous thresholds. In this way we overcame the problem of having a fully connected network and found the intrinsic structure of the functional architecture of the brain.

Jyothika Kumar, Sarina Iwabuchi, Birgit Völlm, Lena Palaniyappan

The default mode network (DMN) is now known to play an important role in social cognition. Thus, we hypothesized that the social neuropeptide oxytocin (OXT) will modulate the connectivity of the DMN. We used Granger Causality Analysis and found that intranasal OXT modulates the effective or ‘causal’ connectivity between the precuneus: a key DMN node and the dorsolateral prefrontal cortex, a key region in the central executive network. Thus, OXT has the potential to enhance the cooperative role of the DMN, which could explain the mechanistic action by which OXT improves social cognition in disorders such as autism and schizophrenia.

Yi He, Maosen Wang, Xuming Chen, Xin Yu

The vascular dynamic network connectivity was detected with the resting-state fMRI in rodent and human brains (abstract: 3115). However, the basis of vascular dynamic connectivity is unclear. Here, the GCaMP6-mediated calcium signal simultaneously detected by fiber optics with fMRI showed slow-freuqncy fluctuation (0.01-0.04Hz) correlated to the single-vessel fMRI signal fluctuation with lead times from 1 to 5 seconds. In addition, the correlation was observed on the slow-frequency oscillation of the power profile of the spontaneous calcium burst spikes with frequency bandwidth of 1-10Hz. Thus, the vascular dynamic network connectivity demonstrates the hemodynamic state changes coupled to the brain state fluctuation. 

Xianchang Zhang, Hewei Cheng, Zhentao Zuo, Ke Zhou, Bo Wang, Lin Chen, Yong Fan, Rong Xue

Functional subspecialization of human amygdala has been revealed in a variety of studies based on histological, in-vivo imaging, and meta-data. However, most of the existing studies identified functional subregions of amygdala at a group level. In this study, we investigated individualized functional neuroanatomy of amygdala based on 7T resting-state fMRI data with high spatiotemporal resolution. Our results have demonstrated that an improved semi-supervised clustering algorithm successfully parcellated individual subjects’ amygdala into 3 subregions, each of them having distinctive functional connectivity patterns. The individualized functional subregions of amygdala may better capture individual variability in functional neuroanatomy than their group level counterparts.

Jie Huang, David Zhu

Areas across the visual cortex are functionally connected. A stressful striped pattern induces perceptual illusions/distortions and visual discomfort in most people, headaches in patients with migraine, and seizures in patients with photosensitive epilepsy. In contrary, a non-stressful striped pattern does not induce such effects. This study found that a 25-min visual stimulation showed a significantly contrary effect of the stressful vs. non-stressful striped patterns on human visual cortical functional connectivity (FC). To the contrary of the strengthening effect of the stressful striped pattern on the FC, the non-stressful striped pattern showed a weakening effect on the FC.

Yue Cheng, Wen Shen

Purpose: To investigate the impact of prior episodes of hepatic encephalopathy (HE) on post-transplantation brain function recovery. Method: Thirty-three cirrhotic patients (HE, n=15 and noHE, n=18) and 30 healthy controls were included. Functional connectivity strength (FCS) were compared between the pre-LT data and the post-LT data, respectively. Results: For the noHE group, the altered FCS found pre-LT largely returned to nearly normal levels soon after LT. The abnormal FCS prior to LT was largely preserved in the HE group, including high-level cognition-related and vision-related areas. Conclusion: Pre-LT episode of HE may have adverse effects on post-LT brain function recovery.

Karthik Sreenivasan, Virendra Mishra, Zhengshi Yang, Xiaowei Zhuang, Sarah Banks, Dietmar Cordes, Ryan R Walsh

The objective of this study was to use resting-state functional connectivity and graph theory to determine how the topology of the network is altered in PD with respect to severity of motor dysfunction. The current study revealed altered functional connectivity and topological properties of networks in PD with respect to severity of motor dysfunction. Our results point to a shift towards a less efficient network topology with altered integration and segregation in more motorically affected patients.

Jun Hua, Martin Kronenbuerger, Xinyuan Miao, James Pekar, Peter van Zijl, Christopher Ross

Huntington’s disease (HD) is a neurodegenerative disorder characterized by motor, cognitive and behavioral deficits. The striatum is one of the first brain regions that show detectable atrophy in HD. Reduced functional connectivity between striatum and motor cortex has been reported. Here, we report decreased motor-striatal connectivity but increased fronto-striatal connectivity in early/premanifest HD patients. We speculate that this may imply a compensatory mechanism, where additional cortical regions are recruited to subserve functions that have been impaired due to HD pathology. We also found strong correlations between functional connectivity and genetic measures, suggesting its potential value as a biomarker for HD.

Oleksii Omelchenko, Zinayida Rozhkova, Irina Karaban, Mykola Makarchuk

We hypothesized that audio-motor transformation (AMT) play an important role in voice-guided movement initiation with STN involvement. We propose AMT-related subthalamic nucleus  activation analysis in lateralized PD for tremor asymmetry influence study. We identified PD symptoms laterality dependent STN activation peculiarities. Obligatory left STN activation in AMT supposes its role in motor command switching. Bilateral STN activation during the movement execution supports its proposed role as a motor error correction node.

Haiguang Wen, Junxing Shi, Kuan Han, Zhongming Liu

The principle of cortical representations when thousands of real-life objects and categories are involved remains unclear. Here, we built a computational model of the human visual system by using a deep neural network and predicted the cortical responses to natural visual stimuli. In particular, we trained the model by using fMRI data obtained while subjects watched very long (>10 hours) natural movie stimuli that contained thousands of visual object categories. Based on the model, we systematically analyzed the activation patterns in the brain induced by different kinds of object categories. We found that the categorical information was represented by distributed and overlapping cortical networks, as opposed to discrete and distinct areas. Three cortical networks represented such broad categories as biological objects, non-biological objects, and background scenes. More fine-grained categorical representations in the brain suggest that visual objects share more (spatially) similar cortical representations if they share more similar semantic meanings. 

Jing Liu, Zhizheng Zhuo, Juan Wei, Queenie Chan, Xiaoying Wang

Brain function MRI (fMRI) could successfully demonstrate that differences in the pattern of brain activity to lower back pain (LBP) can be used as a neurological marker to distinguish between individuals with and without LBP. Medical, legal and business professionals have recognized the importance of this research topic and of developing objective measures of LBP and other chronic pain.

Shuaiwen Wang, Junqiang Lei, Shunlin Guo

Parkinson's disease (PD) is the second most common neurodegenerative disease after AD, and the most frequent subcortical degenerative disease.We hope to found  morphological and functional characteristic change in PD

Bingjiang Lyu, Jianqiao Ge, Zhendong Niu, Li Hai Tan, Tianyi Qian, Jia-Hong Gao

Spoken language comprehension relies on both the identification of individual words and the expectations arising from contextual information. A distributed fronto-temporal network is known to facilitate the mapping of speech sounds onto corresponding meanings. However, how prior expectations influence this efficient mapping at the neuroanatomical level, especially for individual words, remains unclear. Using functional magnetic resonance imaging, we addressed this question in the framework of the dual-stream model by investigating both the neural substrates and their mutual functional and effective connectivity. Our results revealed how this ubiquitous sound-to-meaning mapping in daily communication is achieved in a predictive manner.

Catherine Foster, Jessica Steventon, Daniel Helme, Valentina Tomassini, Richard Wise

We measured the association between aerobic fitness and cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) in young, healthy adults using multiple inversion time (MTI) arterial spin labelling (ASL), with a hypercapnic challenge to assess CVR. The results show that higher fitness is associated with lower baseline CBF and greater CVR. Although studies with a larger sample size are required to clarify the relationship between fitness and cerebrovascular function in early adulthood, the current results suggest that aerobic fitness may promote vascular efficiency and reserve.

Toni Karvonen, Arno Solin, Ángel García-Fernández, Filip Tronarp, Simo Särkkä, Fa-Hsuan Lin

We analyze the structure of physiological noise in the $$$k$$$-space of BOLD fMRI. We use DRIFTER which is an algorithm based on optimal Bayesian smoothing techniques for  separation of the fMRI signal to a BOLD signal component and physiological noises. DRIFTER is run independently for each spatial frequency and it is shown that the physiological noise lies in the $$$k$$$-space points with low spatial frequency and that its amplitude is proportional to the BOLD signal. This result suggests that we can lower the computational burden without losing estimation accuracy by running DRIFTER only on a subset of $$$k$$$-space points.

James Duffin, Olivia Sobczyk, Adrian Crawley, Julien Poublanc, Kevin Sam, Lashmi Venkatrahavan, David Mikulis, Joseph Fisher

Conventional measurements of cerebrovascular reactivity (CVR) are often based on the BOLD changes in response to a ramp CO₂ stimulus ranging from hypo- to hypercapnia.  Using a simple model of two vascular beds, one with a healthy standard reference resistance, competing for the same limited blood supply, we derive the sigmoidal relative resistance changes in the other branch of the model from measured BOLD responses.  Maps displaying the spatial pattern of the relative resistance sigmoid parameters describe the physiology and pathophysiology of the vessels themselves and thus may provide more clinically useful insight. 

Michael Hütel, Andrew Melbourne, Dave Thomas, Jonathan Rohrer, Sebastien Ourselin

Variations in the heart and respiration rate have an impact on BOLD-fMRI signal variations. The cardiac cycle causes a pulsatile arterial blood flow which causes slice-specific signal changes resulting in artificial correlations between voxels within the same slice. The introduction of multi-band (MB) EPI acquisitions such as in the Human Connectome Project (HCP) increase such artificial correlations because many slices are acquired at the same slice time. We find physiological-related spatial Independent Components (ICs) and remove their corresponding time courses from BOLD-fMRI scans. Our method RICERCAR outperforms RETROICOR as well as FIX.

Caroline Bendell, Shakeeb Moosavi, Mari Herigstad

Carbon monoxide (CO) is a cerebral vasodilator, yet effects of low-level CO exposure (from e.g. smoking) on BOLD FMRI remain unknown. We scanned 12 never-smokers at 3T before and after inhaling low-level CO (or air as a control). CO significantly reduced BOLD response to carbon dioxide during breath holds and attenuated visual cortex activation during visual stimulation and fingertapping, but also increased premotor cortex activation during fingertapping. This indicates that CO generally dampens BOLD signal (possibly through elevated baseline CBF), but that the effect may be task- and/or region-dependent. Caution should be exercised when comparing populations with different CO levels.

Daniil Aksenov, Limin Li, Michael Miller, Robert Linsenmeier, Alice Wyrwicz

A comprehensive understanding of the relationship between neuronal activity and oxygen dynamics in the brain is vital for the accurate interpretation of fMRI results. This study investigates the relationship between changes in blood and tissue oxygen as well as neuronal activity in the awake and anesthetized states.  We compare BOLD, PO₂ and electrophysiological signals in the barrel cortex during whisker stimulation in awake and isoflurane-anesthetized rabbits.  Our findings suggest that the relationship between BOLD, PO₂ and electrophysiological responses is considerably different in the awake and anesthetized states.

Ali Golestani, Luxi Wei, Jean Chen

Cerebrovascular reactivity (CVR) is commonly mapped as the response of the blood oxygenation level dependent (BOLD) signal to a hyper/hypocapnic breathing challenge, which might be intolerable for some patients. We proposed a method to estimate quantitative CVR using intrinsic fluctuations of end-tidal CO₂ (PETCO₂) during resting-state fMRI data acquisition (rs-qCVR). We validated our rs-qCVR method against the “gold-standard” hyper/hypocapnic CVR method, demonstrating significantly association between the two in the majority of the healthy subjects. 

Tatsuya Arai, Felix Horn, Rui Sá, Madhwesha Rao, Guilhem Collier, Rebecca Theilmann, G. Prisk, Jim Wild

Two multi-breath imaging techniques for quantifying specific ventilation based on oxygen enhanced ¹H and hyperpolarized 3He gas MRI were cross-validated with spatially matched data from the same subjects. With a custom RF torso ¹H array configured with ³He T-R coil in situ we were able to separately acquire ¹H and hyperpolarized ³He MRI during a single scanning session without repositioning the subject. The preliminary study demonstrated qualitative as well as quantitative similarities between the two techniques.

Catherine Foster, Jessica Steventon, Ian Driver, Daniel Helme, Valentina Tomassini, Richard Wise

Recovery of motor function following neurological damage is dependent on functional neuroplasticity. Mechanisms of adaptive plasticity are not well understood, thus limiting the ability to predict recovery following rehabilitation. This study examined the suitability of calibrated fMRI to study cerebrovascular changes during motor learning, as cerebrovascular function plays an important role in neuroplasticity. Results showed cerebral blood flow, BOLD and oxygen metabolism increases from rest with task but decreases with task-learning. However, high inter-subject response variability was observed. Calibrated fMRI shows promise for studying cerebrovascular changes during learning but the repeatability and stability of measurements requires further investigation.

Saskia Bollmann, Alexander Puckett, Ross Cunnington, Markus Barth

We investigated the influence of physiological noise on statistical inference in fMRI at the single-subject level. By comparing two SMS sequences with a short and a long TR, we explored the interaction between repetition time, physiological noise modelling and the autoregressive model used to characterize serial correlations in fMRI data. Using variational Bayesian inference, we found that fMRI acquisitions with a short TR require accurate modelling of cardiac and respiratory processes to successfully remove serial correlations from the fMRI time series. For the SMS sequence with a longer TR, the standard AR model of order 1 proved sufficient.

Shruti Agarwal, Haris Sair, Sachin Gujar, Arvind Pathak , Jay Pillai

Neurovascular Uncoupling (NVU) can critically limit presurgical mapping using blood oxygen level dependent functional magnetic resonance imaging (BOLD fMRI). False-negative activations caused by NVU can lead to erroneous interpretation of clinical fMRI examinations. Brain tumor-related NVU has been previously demonstrated on task-based BOLD fMRI (tbfMRI) and resting state BOLD fMRI (rsfMRI). The purpose of this study is to demonstrate that NVU in the sensorimotor network can be similarly detected on rsfMRI and BH CVR maps as evident in the criterion standard tbfMRI. 

Celia Dong, Russell Chan, Leon Ho, Alex Leong, Eddie Wong, Lei Wang, Felix Chen, Condon Lau, Ed Wu

The hippocampus is associated with the memory and learning, meanwhile, receives signal from all sensory system indirectly. However, whether and how the hippocampus influences sound processing in the auditory system remains unclear. Our recent study showed that optogenetic stimulation of hippocampus enhances the brain bilateral auditory cortex connectivity. This fMRI study investigated the influence of hippocampus on auditory processing in the inferior colliculus (IC) by using tetrodotoxin (TTX) to pharmacologically deactivate the dorsal hippocampus. For the first time, our results revealed that the dorsal hippocampus plays a dynamic role in shaping the IC auditory response. 

Yong Zhang, Zhongping Zhang, Kang Wang, Zhenyu Zhou

Quantitative measurement of oxygen delivery and consumption in the brain can provide insight into neurovascular and metabolic coupling. A single shot asymmetric spin echo (ASE) EPI sequence was implemented for quantitative oxygen extraction fraction (OEF) measurement in healthy volunteers for the feasibility study. OEF results were in good agreement with the normal range of 30%-40% reported in the previous literature. ASE EPI shows the potential to provide quantitative OEF maps with good brain coverage and without the need of gas challenges. Further investigation is required to evaluate the sensitivity of OEF measurement in the disease situation, such as stroke.

Zhengshi Yang, Ryan Walsh, Virendra Mishra, Karthik Sreenivasan, Xiaowei Zhuang, Sarah Banks, Dietmar Cordes

Eigenvector centrality (EC) is a parameter-free method to measure the centrality of complex brain network structures without a priori assumption. It is here applied to resting state fMRI data acquired from normal controls (NC) and Parkinson’s disease (PD) subjects for the purpose of detecting centrality abnormality in PD, a disease known to impact neural networks diffusely. The features extracted from EC were able to accurately classify subjects when used with linear discriminant analysis and support vector machine. 

Lei Wang, Celia Dong, Alex Leong, Xunda Wang, Leon Ho, Russell Chan, Felix Chen, Ed Wu

Periodicity is inherent in numerous external sensory stimuli. However, its effect on large-scale resting state brain networks has not been fully understood. This study investigated brain networks before and after periodic visual stimulation in low frequency (1Hz) using resting state functional MRI. Enhanced connectivity in visual, temporal, salience and ventral attention networks were detected after 1Hz visual stimulation. Furthermore, power spectrum analysis showed increase in infra-slow (<0.1Hz) rsfMRI activity. These findings suggest that slow and periodic visual stimulation initiates and/or facilitates certain neuromodulatory mechanisms such as neural oscillations, leading to increased rsfMRI connectivity. 

Shruti Agarwal, Hanzhang Lu, Jay Pillai

The phenomenon of neurovascular uncoupling (NVU) is an under-recognized but very important limitation of clinical BOLD fMRI because it can lead to non-visualization of eloquent cortex and resultant inadvertent surgical resection of vital brain tissue leading to permanent postoperative disability. In this study we demonstrate a novel method for correcting for the spuriously decreased ipsilesional motor activation associated with NVU through use of a novel resting state fMRI (rsfMRI) frequency domain metric-- ALFF (amplitude of low-frequency fluctuation)-- in patients with perirolandic low grade gliomas.

Xiaowei Song, Hui Guo, Sujoy Ghosh-Hajra, Careesa Liu, Yunting Zhang, Ryan D'Arcy

Impaired white matter (WM) integrity is common in Alzheimer's disease (AD), in addition to gray matter degeneration. While fMRI has been widely used in understanding the disease-associated changes, results so far have omitted the WM even though WM activation has repeatedly been reported in healthy younger adults in recent fMRI studies. Here we applied three tasks targeting interhemispheric transfer at 3.0T to extend the WM fMRI research to clinical applications in AD-dementia. The study detected fMRI activation in the corpus callosal WM in 87% individuals with early AD and normal cognitive aging (NC), and a difference between AD and NC.

Rebecca Klee, Thomas Mueggler, Andreas Bruns, Nicole Wyttenbach, Antonio Ricci, Rodolfo Gasser, Markus von Kienlin, Basil Künnecke

Etomidate has recently been proposed as a hypnotic for high-fidelity fMRI in mice. It largely preserves cerebrovascular autoregulation and basal perfusion, thus providing a large window for hemodynamic-based fMRI readouts. However, commercially available formulations of etomidate come at low concentration and are suitable only for intravenous infusion, hence resulting in large infusion volumes and difficult procedures in small rodents. Here, we demonstrate that fMRI-compatible anaesthesia can be readily achieved upon subcutaneous administration of etomidate formulated as aqueous solution. We further propose to substitute etomidate with its short-acting analogue cyclopropyl-methoxycarbonyl metomidate to avert long recovery times due to subcutaneous depot formation.

Sun Young Chae, Geun Ho Im, Jisu Hong, Moon-Sun Jang, Hyunjin Park, Jung Hee Lee

Unlike blood oxygen level dependent (BOLD)-fMRI, accurate physiologic adjustment for subjects during rs-fMRI data acquisition does not seem to be critical for the quality of the final data. In this study, we performed rs-fMRI measurements during normal and abnormal physiological conditions and analyzed betweenness centrality (BC), degree centrality (DC) and eigenvector centrality (EC). In this study, we demonstrate that physiologic conditions seem to have a direct effect on the rs-fMRI result. Thus, the results of our current study suggest that normal physiologic condition should be maintained for rs-fMRI data acquisition.

Deepika Bagga, Karl Koschutnig, Bhageshwar Mohan, Christoph Aigner, Johanna Reichert, Peter Holzer, Veronika Sch?pf

The present study investigated the effect of probiotic administration on emotional memory in healthy volunteers using fMRI. The preliminary results showed that probiotic intake for 4-5 weeks improved the response accuracy significantly and this was accompanied by a decrease in the neural activity in the brain areas associated with emotions and memory formations. This decrease was more prominent for unpleasant stimuli as compared to neutral stimuli. Considering the scarce literature on gut microbiota and brain interactions in humans, our findings might provide a gateway for further understanding of mechanisms of gut-brain interactions and their effect on emotions and memory.

Benjamin Conrad, Satoshi Maki, Jennifer Watchmaker, Bailey Box, Robert Barry, Seth Smith, John Gore

A hypercapnic gas challenge was used to demonstrate blood oxygenation level dependent (BOLD) signal changes in the cervical spinal cord, and the sensitivities of two functional acquisition sequences (standard single shot (GE-EPI) and 3D multishot (3D-EPI) gradient echo EPI) were compared. Results indicated that both acquisitions were able to detect signal changes of about 1% in gray matter and higher values in white matter confirming that BOLD effects in the cord are reliable. The 3D multishot sequence exhibited higher temporal SNR and reduced susceptibility distortions, making it an attractive option for BOLD fMRI in the spinal cord.

Nicolas Coquery, Paul Meurice, Régis Janvier, Eric Bobillier, Stéphane Quellec, Hervé Saint-Jalmes, David Val-Laillet

The minipig model is of high interest for brain research in nutrition and associated pathologies considering the similarities to human nutritional physiology, brain structures and functions^1,2 . In the context of a gustatory stimulation paradigm, fMRI can provide crucial information about the sensory, cognitive and hedonic integration of exteroceptive stimuli in healthy and pathological nutritional conditions. To date, this is the first intent to describe gustatory stimulation in minipigs using fMRI.

Jan Schluesener, Xin Yu

The lateral hypothalamus (LH) is a central node of the brain to mediate brain states. It is comprised of highly heterogeneous neuronal populations and diverse projections. It remains elusive how different neuronal LH subdivisions mediate the brain state. Here, we developed an optogenetic method to map LH functional projections and investigate functional connectivity upon LH activation. Optical stimulation of the LH can directly activate the preoptic area, central thalamus and the subiculum area, and increase the cortical resting-state correlation. This work makes it possible to further target different LH neuronal populations and decipher cell-type specific functional projections.

Chen-You Huang, Chiun-Wei Huang, Shao-Chieh Chiu, Wu-Chung Shen, Shin-Lei Peng

Previous rat fMRI studies have been analyzed by statistical parametric mapping (SPM) but the SPM is designed for human fMRI studies. In this study, we examine whether the default settings including delay time, statistic methods and hemodynamic response function (HRF) shape in SPM can directly transform to rat fMRI studies. Results show statistic methods do not affect the mapping of brain activation. However, the delay time and HRF shapes have significant impacts on extracting brain activation, especially in primary somatosensory cortex and striatum. We therefore suggest the HRF should be optimized to approach better sensitivity in other rat fMRI studies.

Molly Bright, Christopher Tench, Kevin Murphy

In resting-state fMRI nuisance regression, a General Linear Model (GLM) is employed to fit and remove the variance associated with a noise model. Without "ground-truth" knowledge, the noise models must be tested and improved to obtain accurately cleaned datasets without "throwing the baby out with the bath-water." Valid statistical inference on a GLM fit requires normally-distributed residuals, which is not the case when intrinsic brain fluctuations are present. We demonstrate that existing pre-whitening tools can be appropriately applied to account for serial autocorrelation in resting-state fluctuations during nuisance regression, allowing statistical differentiation of true and simulated noise models.

Nadège Corbin, Guillaume Flandin, Oliver Josephs, Nick Todd, Karl Friston, Martina Callaghan

In fMRI, functional sensitivity is dictated by many factors related to the data acquisition scheme, most notably image SNR, temporal resolution and the number of samples acquired. Advanced acquisition techniques, such as 2D multiband imaging, are popular for fMRI studies because they afford the possibility of greatly increasing temporal resolution allowing more samples to be acquired per unit time, but at the cost of image SNR and increased temporal auto-correlations. This study uses the General Linear Model framework to disentangle these effects and determine the net impact on functional sensitivity, as parameterised via temporal SNR and t-scores.

Zhengshi Yang, Xiaowei Zhuang, Tim Curran, Richard Byrd, Virendra Mishra, Karthik Sreenivasan, Dietmar Cordes

Spatially adaptive multivariate methods were applied in fMRI activation analysis to alleviate low sensitivity in commonly used Gaussian smoothing single voxel analysis. Usually these methods require constraint to avoid the curse of high degrees of freedom. We have developed a novel spatially adaptive kernel canonical correlation analysis method, which does not require constraint and has superior performance compared to other methods.

Shruti Agarwal, Hanzhang Lu, Jay Pillai

In brain tumor patients, coupling between neuronal activity and BOLD response is often disrupted (known as neurovascular uncoupling (NVU)), resulting in dangerous underestimation of true extent of eloquent cortex in pre-surgical planning. With increasing popularity of resting state fMRI (rsfMRI) for presurgical mapping, it becomes critical to investigate effects of NVU in rsfMRI. A recent study demonstrated that tumor-related NVU can impact resting state functional connectivity within the sensorimotor network as assessed using a seed-based correlation analysis (SCA).2 We now explore whether NVU may also affect the rsfMRI frequency domain metrics ALFF (amplitude of low-frequency fluctuation) & fALFF (fractional ALFF).

Jia Fan, Ernesta Meintjes, A Alhamud

Resting state fMRI (rs-fMRI) used to detect and evaluate resting state functional connectivity (RSFC) in both healthy subjects and patients. However, the reproducibility of rs-fMRI may be influenced by the time of day when the scan is performed. In this work, we investigated the reproducibility of resting state networks by comparing scans performed in the morning (immediately after the scanner was switched on) and again in the late afternoon (after all daily scans were done) on six different days. Our results showed higher RSFC in afternoon scans in 5 regions within 5 networks .

Shruti Agarwal, Haris Sair, Jay Pillai

The validity of BOLD fMRI in pre-surgical planning may be severely  compromised due to disruption of the normal coupling between neural activity and the consequent microvascular blood flow response (neurovascular uncoupling, or NVU). The effects of brain tumor-induced NVU on resting state BOLD fMRI (rsfMRI) have been previously described through seed-based correlation analysis (SCA). In this study, we evaluated regional homogeneity of resting state fMRI data using Kendall's coefficient of concordance (KCC-ReHo) & Coherence (Cohe-ReHo) metrics and compared these results with those of “gold standard”motor task-based (tbfMRI) activation to determine their effectiveness in detecting NVU in the sensorimotor network.

Cesar Caballero-Gaudes, Oihane Ezama, Manuel Delgado-Alvarado, Maria Cruz Rodriguez-Oroz

This work proposes a novel method for the classification of ICs in resting-state fMRI data based on sparse paradigm free mapping (PFM), a deconvolution approach that enables detecting BOLD events without prior information of their timing. This approach uses a single temporal feature, the significance of the deconvolution model estimated with PFM. Our results demonstrate that despite its simplicity this approach achieves similar sensitivity in classifying the neuronal-related BOLD components to the more complex classification method of ICA-AROMA, but with less specificity in classifying noise components. In addition, it can improve the identification of physiological noise components. 

Joana Pinto, Sandro Nunes, Marta Bianciardi, Afonso Dias, Luis Silveira, Lawrence Wald, Patricia Figueiredo

Several strategies have been proposed for correcting physiological noise in rs-fMRI, including different models of respiratory volume (RV) and heart rate (HR) effects. Although group-level model optimization has often been employed, it has been reported that these effects are highly variable across subjects and brain regions. Here, we investigated the impact of optimizing the time-lags of RV and HR physiological noise contributions at different levels of specificity in 7 Tesla rs-fMRI. We found that a regional optimization based on a clustering approach taking into account the time-lags’ individual spatial variability explained more fMRI signal variance than group or subject-based optimizations.

Arash Foroudi Ghasemabadi, Mahdi Khajehim, Vahid Malekian, Abbas Moghaddam

Non-balanced SSFP has been recently suggested as a viable approach for T2-weighted SSFP fMRI. Compared to bSSFP, it entirely eliminates the problematic banding artifacts. However, its sensitivity has not yet been systematically investigated.  In this study, fixed effects group analysis was performed on balanced and non-balanced SSFP data from seven healthy subjects in 7 T. We found that, group activation maps are generally similar, besides, mean z-values for the two methods are not significantly different. The obtained results suggest that the newly developed nbSSFP method is a viable approach to substitute bSSFP in high resolution fMRI studies.

Parul Chachra, Suresh Joel, Rakesh Mullick, Radhika Madhavan

Resting-state functional magnetic resonance imaging (rs-fMRI) has been suggested to provide key understanding of large-scale network organization in human brain. Harnessing rs-fMRI, we have examined the relationship of seed-based connectivity (SBC) with amplitude of low-frequency fluctuations (ALFF) and fractional ALFF (fALFF). We recorded rs-fMRI from healthy volunteers and measured regional ALFF, fALFF and SBC. We demonstrate that ALFF and fALFF were weakly correlated to SBC and the correlation was specifically stronger for selected networks. Our results suggest that ALFF/fALFF and SBC may be driven by the same underlying factors and thus co-vary in a similar manner.

Yang Fan, Jing Wang, Bingjiang Lyu, Bing Wu, Zhenyu Zhou

Recently, a novel technique was proposed directly integrated resting-state fMRI and DTI to construct a local spatio-temporal correlation tensor from resting state fMRI data. In individual level, the functional correlation tensor can be used to tract white matter fibers. However, there is no knowledge of group level property of functional correlation tensor. In the present study, group averaged tensorial properties (e.g. FA and trace) of functional correlation tensor were investigated.  It is shown that the group averaged trace map of  functional tensor can reveal default mode network. And our results are consistent across different datasets.

Alexander Cohen, Andrew Nencka, Yang Wang

A novel multiband multi-echo ASL sequence was employed to collect high-resolution, whole-brain simultaneous ASL/BOLD fMRI data. Four echoes were collected allowing multi-echo independent component analysis (ME-ICA) denoising to be applied to both the BOLD and ASL data. Subjects performed a finger-tapping task, and activation was compared between datasets with and without denoising. The multi-echo denoised BOLD dataset detected the most activation compared to activation calculated using the combined echoes and only the second echo. Additional activation was observed for the denoised perfusion-weighted data compared to the original perfusion-weighted data. There was also less spurious negative activation for the PWDN data. 

Yanlu Wang, Ivanka Berglund, Martin Uppman, Tie-Qiang Li

Quantitative data-driven analysis (QDA) has shown to be robust and intuitive method to extract functional connectivity information from resting-state fMRI data for group-level comparison. In this study, the QDA method is applied to patients suffering from epileptic seizures. Multiple brain regions of significant (p<0.01) differences were detected. The results are consistent with published works in temporal lobe epilepsy and frontal lobe epilepsy in literature using invasive methods. All brain regions experience down-regulation in functional connectivity in epilepsy patients compared to healthy control subjects.

Xiaowei Zhuang, Zhengshi Yang, Virendra Mishra, Karthik Sreenivasan, Dietmar Cordes

A new HRF estimation method was introduced to improve the accuracy in recovering HRFs with wider frequency range. This non-smooth optimization problem was solved via BFGS technique. Results from simulated data demonstrate the accuracy and reliability of this new method in recovering HRF. Results from an event-related fMRI dataset further demonstrate the ability of the proposed method in capturing the variation of HRFs across different brain regions and subject populations.

Kaundinya Gopinath, Simon Lacey, Randall Stilla, Venkatagiri Krishnamurthy, Krish Sathian

Recent studies have shown that cluster-wise family-wise error rate (FWE) corrected inferences made in parametric statistical methods based fMRI studies over the past couple of decades were invalid due to incorrect these methods incorrectly specifying that spatial auto-correlation functions (sACF) of fMRI data had a gaussian shape. In this study we proposed a method to obtain fMRI inferential statistic residuals with gaussian sACF. Results show that this method substantially increases the detection power of group-level inference tests while not significantly changing the voxelwise statistic maps. Additionally it makes inferences based on assumption of gaussian sACF valid again.

Saskia Bollmann, Steffen Bollmann, Alexander Puckett, Andrew Janke, Markus Barth

Motion dominates the contribution to variance in fMRI time series and it is therefore important to account for this variability correctly. Currently, most correction schemes use a rigid body realignment procedure, but interactions with magnetic field inhomogeneities and physiological fluctuations lead to non-linear deformations. Non-linear realignment increased spatial resolution by harvesting sub-voxel shift information with little impact on tSNR. Activated regions showed a better delineation with a clear match to anatomical features. Importantly, our proposed method can be applied to already acquired fMRI data sets to improve spatial conspicuity.

Gengyan Zhao, Vivek Prabhakaran, Elizabeth Meyerand, Rasmus Birn

Independent component analysis (ICA), as a data-driven signal decomposition method, has been widely used in fMRI. Sources of the measurement can be separated according to the rule of maximum independency, but it usually cannot naturally generate a source which is highly correlated with the signal we are interested in. To solve this problem, we propose a new method, prior knowledge oriented ICA (pICA), to drive ICA to a set of sources with the SOI among them. Experiments of simulation and fMRI show this new method has higher specificity and accuracy in identifying the SOI and its corresponding spatial map.

Niharika Gajawelli, Bradley Voytek, Danny Wang, Berislav Zlokovic, Arthur Toga, Meng Law, John Morris, Tammie Benzinger, Judy Pa

The power spectrum of the functional MRI (fMRI) signal is 1/f-distributed: the power (P) is proportional to inverse frequency (1/f) with scaling factor (B), the power law exponent (PLE). The PLE, in electrophysiology, may reflect the relative balance of excitation and inhibition. Here, we examine the PLE of fMRI power spectrums in the default mode network in older adults with a clinical dementia rating score of 0, 0.5, or 1. PLE analysis may help us understand the potential regional inhibitory/excitatory balance of underlying architecture, given that the BOLD signal is a surrogate marker of local field potentials and post-synaptic processes.

Haojie Li, Yonghong Hao, Daoyu Hu, Zhen Li

Because of different subtypes of RCC have different prognoses and respond differently to targeted therapies, accurate identification of the specific diagnosis prior to treatment is important. In this study, our results demonstrate that the combination of r-FOV DWI and the whole-lesion histogram analysis method may help in the interpretation of DWI of small renal masses and determine the optimal ADC parameter for quantitative assessment. The 75th percentile ADC value was more reliable than other histogram parameter values in distinguishing clear cell from non-clear cell RCCs with high sensitivity and specificity, potentially improving the accuracy of pretreatment diagnosis and selection of clinical therapy.

Xi Wu, Zhipeng Yang, Stephen Bailey, Jiliu Zhou, Laurie Cutting, John Gore, Zhaohua Ding

Functional magnetic resonance imaging has been widely used in measuring functional connectivity between cortical regions, but it has not been well-established in white matter to date. While we have previously demonstrated that resting state BOLD signals exhibit structure-specific correlations, suggesting that neural activities may be encoded in white matter BOLD signals as well, in this study we further confirm that functional stimulations can induce activities in relevant white matter pathways.

Amanda Taylor, Jung Hwan Kim, David Ress

Functional magnetic resonance imaging (fMRI) measures the hemodynamic response to neural activation. Brief periods (2 s) of multisensory neural stimulation evoke the hemodynamic response function (HRF) across the majority of cerebral cortex. High (2 mm) spatial resolution enables the characterization of the HRF restricted to the gray matter, avoiding partial volume effects into nearby white matter and vascular tissue. HRF amplitude and timing measurements from eight healthy subjects showed temporal stability and stereotypical spatial amplitude patterns, suggesting that this method could be adapted to diagnose pathologies associated with abnormal neurovascular coupling.

Cameron Trapp, Kishore Vakamudi, Stefan Posse

We analytically investigate the characteristics of a recently developed sliding window methodology designed for real time analysis of resting state connectivity. The suppression of various types of confounds is investigated both in this analytical framework and numerically. It is shown that this methodology not only acts as a high pass filter and denoiser, but behaves as a model free despiking and confound suppression tool.

Karsten Mueller, Jöran Lepsien, Harald Möller, Gabriele Lohmann

Recently, Eklund et al published a manuscript discussing the issue of false positive results in functional MRI (fMRI) using the most common software packages. In their analysis, image upscaling was performed in fMRI preprocessing after registering images into a standard space (normalization). We show that the degree of image upscaling used for normalization impacts the statistical results when using the Gaussian Random field approach. A higher upscaling generally leads to smaller p-values increasing the number of false positive clusters. This result is quite troubling because statistical inference should not depend on a preprocessing parameter which can be chosen ad libitum.

Dong Zhang, Changzheng Shi, Rong Ma, Zhongping Zhang, Liangping Luo

People with high risk of diabetes exhibited decreased ReHo in right temporal lobes, left pallidum/ lenticular nucleus/insula/Heschl gyrus and left cingulate cortex and declined fALFF in left Heschl gyrus, left supramarginal gyrus and left cingulate cortex, which is consistent with type 2 diabetes mellitus (T2DM) patients. These abnormal regions may be regarded as the endophenotype of T2DM in resting-state BOLD-fMRI.

Sunita Gudwani, Senthil Kumaran, Rajesh Sagar, SN Dwivedi, Naranamangalam Jagannathan

Reading necessitates skill mastering of phonological (sound to letter), orthographic (knowledge of letter identities, position), and semantic (words meaning) processing requiring optimal interface of ventral-dorsal routes. Dyslexia, a developmental reading disorder, is an umbrella term with heterogeneity of behavioral deficits constrains the management efficiency. Persistent deficits lead to emotional, academic, social consequences necessitating evidence-based interventions. The study was planned on neurobiological-model to customize the therapeutic management. Dorsal pathway (BOLD activation) reorganization associated with improvement in reading rate, accuracy, spelling and writing flow suggest neurobiological normalization in dyslexics observed post-remediation on comparing therapy group with non-therapy and age-matched typical readers.

Trey Shenk, Meghan Robinson, Thomas Talavage

There is growing concern that subconcussion could have an effect on the neural health of contact sports athletes. The hemodynamic response was measured and changes were observed in high school football athletes after exposure to impacts.

Marta Vidorreta, Sihua Xu, Fan Yang, Andrew McKinstry-Wu, Alexander Proekt, Brenna Shortal, Hengyi Rao, Max Kelz, John Detre

Dexmedetomidine infusion was used to induce pharmacological unconsciousness akin to natural non-REM sleep, and brain resting-state activity changes were monitored using Arterial Spin Labeling and EEG recordings. 

Our results confirm that functional changes associated with non-REM sleep in both centrencephalic and cortical structures can be monitored with ASL, revealing that selective regional CBF decreases are associated with the loss of consciousness, most significantly in the reticular activating system. The thalamic/cortical GM CBF ratio was also found to be a reliable marker of conscious state.

Letizia Casiraghi, Adnan AS Alahmadi , Karl J Friston , Claudia AM Gandini Wheeler-Kingshott, Egidio D'Angelo

In this pilot study, we investigated whether the non-linear BOLD response to varying grip force (GF) is reproduced when observing others performing the task. We used an fMRI squeezeball paradigm with two conditions: action execution (AE - subjects performed the task) and action observation (AO - subjects watched a video of the task). In both conditions, activations were detected in areas constituting the action execution-observation network and both areas evidenced linear and non-linear relations with the GF. These results indicate that action observation calls on the same context sensitive and high level processing necessary for execution.

Basavaraju Sanganahalli, Peter Herman, Garth Thompson, Fahmeed Hyder

The thalamus is a crucial node in cortical-subcortical circuits important for human emotion, cognition, and memory. While invasive studies in animals have revealed rich anatomical and functional separation of various thalamic nuclei, we sought to parse the different portions of the rat thalamus in relation to tactile (forepaw, whisker) and non-tactile (visual, olfactory) stimuli by high field fMRI (11.7T). We reproducibly detected BOLD activations of VPL, VPM, POM, dLGN, and MDT, where MDT activation is a novel indication of this structure’s involvement during olfactory processing. These results have significance in understanding the role of both cortical-subcortical circuits during sensory integration.

liang zhang, jun chen

Despite the fact that alcohol have impact on human brain function, the mechanism is not yet well understood. In order to detect the changes of blood perfusion information based on PCASL, and to discuss the possible mechanism, we analyze the differences of CBF in 29 healthy volunteers before and after alcohol consumption. The results show that CBF changed significantly in brainstem, bilateral hippocampus, left frontal lobe, bilateral thalamus, corpus callosum, anterior cingulate cortex, bilateral cerebellum, bilateral occipital lobe, cuneus and bilateral temporal gyrus. These abnormal activities may have important value in revealing the mechanism of alcohol in the brain.

Xiaomin Xu, Gaojun Teng

To explore the effect of hearing loss on cerebral perfusion, by using a whole brain arterial spin-labeling (ASL) MRI technique. We recruited 8 hearing loss patients and 6 healthy controls, and identified the cuneus with hypoperfusion in SHL patients which may provide new insights into SHL-associated psychological abnormalities.

Shuangfeng Yang, Shengpei Wang, Yue Liu, Wenfeng Li, Hongbin Li, Jishui Zhang, Yang Fan, Hua Cheng, Huiguang He, Yun Peng

Obstructive sleep apnea syndrome (OSAS) in adults has been demonstrated tobe associated with brain functional and structural changes. However, little is known about the changes in regional synchronization of spontaneous brain activity and spontaneous fluctuations in children with OSAS. In the present study, regional homogeneity (ReHo) analysis and amplitude of low-frequency fluctuation (ALFF) based on resting-state functional magnetic resonance imaging (MRI) were used to investigate spontaneous brain activity in children with OSAS compared with controls (CN). As a result, children with OSAS showed significant functional alterations of the cerebellum and temporal gyrus in children with OSAS.

Condon Lau, Eddie Wong, Woody Ho, Bin Yang, Ed Wu

Noise pollution can significantly affect sound processing, even without causing hearing loss. In this study, adult rat subjects are exposed to 100 dB sound level noise for 15 minutes. Functional magnetic resonance imaging (fMRI) and auditory brainstem response (ABR) testing with sound stimulation are performed before, 7 days after, and 14 days after exposure. ABR results show no significant threshold elevation, indicating no significant abnormalities in and near the ear. fMRI results show significant response reductions in the auditory midbrain 7 days after exposure. This suggests transient changes in central auditory gain following acute noise exposure.

Sonja Blankenagel, Ana Beatriz Solana, Brice Fernandez, Christoph Hofstetter, Andreas Dunkel, Thomas Hofmann, Hans Hauner, Jessica Freiherr

Multi-echo planar imaging (MEPI) was explored regarding its ability to overcome the limitations of conventional EPI imaging in studies related to olfaction. MEPI offers great sensibility even in brain regions, which are affected by susceptibility artifacts in EPI imaging. Five subjects were scanned using an event-related olfactory task with both sequences. The subsequent comparison shows that three echoes MEPI has advantages regarding olfaction-related brain activation compared to single echo EPI.

Chunjie Wang, Jian Weng, Yuqiu Liu, Hui Zhou, Feiyan Chen

To examine whether abacus training improves working memory (WM), sixty-four children were randomly assigned into two groups, matched for intelligence. One group received abacus training for five years while the other group had no any abacus experience. WM was measured by a n-back task. The results showed that children with training were more accurate and faster than their peers. They also had greater activation and functional connectivity in the frontoparietal regions. The findings suggest that AMC training may be an effective method to improve WM in school children, which may have implications to help individuals with cognitive deficits.

Shu-Chi Pai, Ying-Hua Chu, Hui-Chuan Chang, Jo-Fu Lin

Previous studies have demonstrated brain activation patterns during musical playing. However, while musical playing with multiple sources of auditory inputs is essential for musical practices and group performance, it is less understood. By using an MR-compatible piano keyboard, the present study compared musical playing with or without acoustic feedback or external timing reference. Functional MRI contrasts showed BOLD signal increase in bilateral Superior Temporal Gyrus and BA 42 during musical playing with an external timing reference, which indicates a neuronal processing pattern relating to the coordination of multiple auditory inputs.

Yilin Zhao, Jun Chen, Hui Lin

Resting-state fMRI reflected spontaneous baseline neuronal activity.The fractional amplitude of low frequency fluctuation (fALFF) and regional homogeneity(ReHo) method had been developed to analyze the blood oxygenation level-dependent signal fluctuations in voxelwise analysis across the whole brain.In this study, we combined two resting-state fMRI algorithm to explore the features of brain spontaneous activities in chronic alcoholics.The results indicated the abnormality activities of some nodes in the default mode network and reward circuit. It is our hope that in future studies this technique may provide the opportunity to examine the integrity of networks involving the above loops in chronic alcoholics.

Sosuke Yoshinaga, Naoya Yuzuriha, Yuri Kitamoto, Mitsuhiro Takeda, Hiroshi Sato, Hiroaki Terasawa

The aim of this study is to evaluate the effects of analgesic agents on the allodynia-specific response in an animal model of fibromyalgia. Before and after the treatment with analgesic agents, BOLD experiments using green laser stimulation were performed. Before the treatments with analgesic agents, S1, IC, and TH exhibited BOLD responses (S1: 1.1%, IC: 0.8%, TH: 0.7%). These responses were inhibited by pregabalin treatment and to a lesser extent by duloxetine treatment (S1: 0.4%, IC: not detected, TH: 0.4%). Our experimental system provides a robust preclinical and clinical evaluation system for new analgesic agents.

liu jie, zhang shi, cheng liang, zhang yong, xu rong, qian long

The study was about the Resting-State fMRI of pilots before and after hypoxic exposure. It proved that the feasibility of monitor the real-time cerebral functional activity change by using MRI. Otherwise, it confirmed that hypoxic exposure inhibited the cognitive functions of pilots to some extent.

Yangwen Xu, Weiwei Men, Tianyi Qian, Thomas Beck, Jiahong Gao, Yanchao Bi

Decades of studies have identified a list of brain areas specific to a certain taxonomic category. However, neural representations incorporating both taxonomic and thematic knowledge are not well understood. In this study, we applied representational similarity analyses to investigate the underlying organizing principles of high-resolution neural activation patterns induced by different categories and themes at different cortical levels. In contrast to taxonomic representation, we did not find specific neural substrates representing thematic knowledge. Instead, neural activation patterns specific to thematic information emerged only when taxonomic differences were controlled for. These results suggest that the brain is dominated by taxonomic knowledge and then modified by thematic knowledge.
 

Hirotsugu Funatsu, Fuyu Hayashi, Sosuke Yoshinaga, Mitsuhiro Takeda, Naoya Yuzuriha, Shunsuke Kusanagi, Hiroaki Terasawa

A BOLD analysis can trace real-time odor responses at high spatial resolution.  Rodents have well-developed olfactory systems, and thus BOLD studies have mainly been performed in rodents.  However, mice have smaller brains and are more susceptible to peripheral hemodynamic changes than rats, which make it harder to obtain sufficient BOLD signals.  This study revealed the real-time odor response in the mouse whole brain by the BOLD experiment with periodical odor stimulations using a high-sensitivity cryogenic probe and the high-detectability analytical method, Independent Component Analysis (ICA).  The signal changes of the activation sites corresponded to the human canonical hemodynamic response function.

Laureline Arnaud, Lucie Ménard, Vincent Gracco

Behavioural and fMRI studies have revealed enhanced auditory abilities and differences in the brain organization of early blind individuals compared to sighted. We used fMRI to assess cortical interactions associated with speech processing of repeated and novel stimuli. Although the in-scanner behavior for the blind and sighted groups were comparable, there were a number of cortical activation and deactivation differences. Additionally, the blind participants were better at a post-scan recall task. Cross-modal recruitment of occipital areas was found in the blind participants. They also showed widespread repetition-enhancement effects, suggesting that additional attention mechanisms contribute to their enhanced auditory word encoding abilities.

Naohiro Jomura, Teppei Shintani, Keisuke Sakurai, Jun Kaneko, Tatsuhiro Hisatsune

A setup for operant learning fMRI was developed and inserted in a horizontal bore 14 T MRI. After the habituation of head-fixed mice, visual stimulation was delivered as CS and a water as reward was supplied automatically in response to licking behavior, for an operant learning task. We analyzed fMRI data between the correct and the error trials and found the BOLD elevation of brain areas including the visual cortex and the hippocampal formation when mice performed the correct trial. Mouse BOLD fMRI in operant learning task will offer unexperienced data to basic as well as clinical research fields.

Vijai Krishnan, Anna Schwartz, William Stokes, Jeff Bulte, Jineta Banerjee, Aline Thomas, Pablo Celnik, Galit Pelled

Spinal cord injury (SCI) leads to severe motor and sensory deficits. New advances in non-invasive neuromodulation technologies such as transcranial magnetic stimulation (TMS) have shown promise in facilitating recovery following brain injuries. Here we tested whether TMS therapy can be developed as a rehabilitative approach in a rat model of SCI. High-resolution functional MRI (fMRI) at 11.7 T was used to detect cortical activity associated with post-injury neuroplasticity. A battery of behavioral tests was used to monitor gross changes in motor behavior. Our results demonstrate that TMS therapy is beneficial in improving post-SCI functional outcomes. 

Kimberly Weldon, Michael-Paul Schallmo, Philip Burton, Andrea Grant, Cheryl Olman

We characterized depth-dependent laminar profiles of surround suppression in human early visual cortex with high-resolution 7T fMRI. In a block-design participants viewed circular target stimuli (gratings defined by sinusoidal luminance modulation) surrounded by an annulus with a grating either parallel or orthogonal to the target grating. The surround was placed either adjacent to the target grating (Near) or separated from the target by 2° of visual angle (Far). Results show a similar activation profile for Parallel and Orthogonal conditions in the Far condition across depth. For the Near condition, contextual modulation occurred more in deep, rather than superficial layers. 

Kevin Aquino, Rodika Sokoliuk, Rosa Sanchez-Panchuelo, Simon Hanslmayr, Stephen Mayhew, Karen Mullinger, Susan Francis

Attentional top-down effects are known to modulate responses when spatially directing attention within sensory modality. The directing of attention between sensory modality is less well understood. Here we present fMRI data using a Posner type attention paradigm between sensory areas (visual and somatosensory). We show that the visual, somatosensory and IPS regions are recruited during attention periods, with some of these areas modulated by degree of attention. Additional IPS regions were modulated strongly with attention recruitment. This paradigm presents top-down influence on cortical regions, allowing the study of the top-down influences of attention switching between sensory modalities.

Nehemia Mekete, An Vu

We demonstrate the utility of the new 7T fMRI movie dataset made publicly available by the WashU-UMinn Human Connectome Project (HCP, www.humanconnectome.org) by reconstructing the movies participants watched, based on their fMRI brain activity and two general models of the human brain: a structural model and a semantic model. Although we were only marginally successful when using the structural model (most likely because participants were allowed to freely view the movie without a fixation task), we were able to successfully decode the semantic content of the held out movie data, with surprisingly high accuracy (r~0.8, and p<10^-10).

Venkatagiri Krishnamurthy, Lisa Krishnamurthy, Dina Schwam, Daphne Greenberg, Robin Morris

Amongst several sources of noise, physiological noise (PN) from cardiac and respiratory cycles affects reliable quantification of rsFC measures such as correlation coefficient (CC). The purpose of this study is to determine the effects of PN on specificity, sensitivity and reproducibility of rsFC maps in a ‘reading’ model. We show that a combination of multiple methodologies to correct for such noise leads to improved signal fluctuations (tSNR) that culminates in higher specificity and sensitivity to neuronal fluctuations that are closer to actual ground truth. Applying our methodologies to a ‘reading’ model, we show that, irrespective of session, correction for PN results in meaningful discrimination of reading networks between typical and struggling readers.

Xirui Hou, Peiying Liu, Micaela Chan, Gagan Wig, Denise Park, Hanzhang Lu

Resting-state fMRI, particular based on Blood-Oxygenation-Level-Dependent (BOLD) signal, has been extensively used to measure functional connectivity (FC) in the brain. A recent report proposed that FC can also be evaluated from hypercapnia BOLD image.  In this work, we aim to systematically compare FC derived from hypercapnia BOLD data with those obtained from traditional resting-state BOLD data in a large cohort (170 healthy participants). Our results suggest that the hypercapnia and resting-state FC maps are spatially correlated across voxels, amplitude-wise correlated across subjects.

Carlo Nicolini, Cecile Bordier, Angelo Bifone

Graph-theoretical analysis has been widely applied to study the modular organization of brain functional connectivity networks. However, existing methods suffer from a fundamental resolution limit. Here, we propose and validate a novel, resolution-limit-free approach dubbed Asymptotical Surprise. Application of this method to human resting state networks reveals the presence of heterogeneously distributed modules, corresponding to neuroanatomically and functionally plausible networks. The finer partition afforded by Asymptotical Surprise enables a more accurate identification of connector hubs, the brain regions that are thought to be responsible for the integration of functionally segregated modules into a cohesive structure. 

Farzaneh Keyvanfard, Abbas Moghaddam

MRI provides the capability of obtaining different information from various aspects of the brain. More comprehensive understanding of the brain can be achieved by combining multimodal brain imaging data. Using Diffusion Tensor Imaging (DTI) in addition to resting state fMRI (rs-fMRI), we have proposed a novel multivariate fusion approach to find supportive structural basis of brain functional networks. Two known functional networks and their counterpart structural networks were extracted through this method.

Hakmook Kang, Hernando Ombao, Chris Fonnesbeck, Zhaohua Ding, Victoria Morgan

Current approaches separately analyze concurrently acquired diffusion tensor imaging (DTI) and functional magnetic resonance imaging (fMRI) data. The primary limitation of these approaches is not to use all available information in estimation of resting state functional connectivity (FC). To overcome this limitation, we developed a Bayesian hierarchical spatio-temporal model that incorporated structural connectivity (SC) into estimating FC, where SC based on DTI was used to construct a prior for FC based on resting state fMRI (rs-fMRI) data. Simulations and data analysis concluded that our model achieved smaller false positive rates and was robust to data decimation compared to the conventional approach.

Robert Becker, Claudia Falfan-Melgoza, Jonathan Reinwald, Wolfgang Weber-Fahr

In a test-retest fMRI experiment we examined the influence of temporal filtering and global signal regression (GSR) on resting state networks in rats. Connectivity and topological properties as well as their test-retest reliability were assessed for eight filtering variants (with and without GSR, four frequency bands). We found GSR to strongly impair the expected structure of networks. The choice of temporal filtering frequencies whereas did not have a significant effect. Test-retest-reliability was low for all filtering variants. Based on our results we recommend to use less restrictive bandpass filters but no GSR.

Yue Cai, Yuan Shi, Yang Fan, Wei Gao, Jiahong Gao

This study proposes an improved method named global functional connectivity stability (GFCS) to quantify the brain dynamic functional connectivity at a voxel-wise level. The GFCS was applied to investigate the overall functional connectivity stability and its correlation with time in infants during the period from late preterm to the term equivalent age (TEA). It is shown that infants presented high functional stability predominantly in the sensorimotor areas, temporal lobe, posterior cingulate cortex (PCC) and medial prefrontal cortex. With time, the frontal areas appeared more variable while the sensorimotor cortex appeared more stable in infants during the neonatal period.

Lihua Chen, Zhizheng Zhuo, Tao Ren, Shuangshuang Xie, Yu Zhang, Wen Shen

To detect the changes of kidney diseases, magnetic resonance imaging(MRI) as a noninvasive approach has been proved to be more suitable for detecting and monitoring diabetic nephropathy(DN). Intravoxel incoherent motion (IVIM) and blood oxygenation level dependent (BOLD) MR imaging have been confirmed their high potential in detecting changes of renal function in patients with chronic renal diseases and transplanted kidneys. 

Kishore Vakamudi, Kunxiu Gao, Cameron Trapp, Greg Scantlen, Stefan Posse

This study introduces a real-time confound-tolerant approach for mapping resting-state network (RSN) dynamics that is compatible with ultra-high-speed fMRI and integrates the following processing steps: (a) iterative optimization of seed selection, (b) sliding-window online detrending of confounding signals, and (c) seed-based sliding-window correlation analysis using hierarchical running averages (meta-statistics) for mapping connectivity dynamics. The method maximizes sensitivity and specificity of mapping RSNs with enhanced suppression of spurious connectivity in WM and GM. This methodology is suitable for online monitoring of data quality, for clinical applications and basic neuroscience research of resting-state connectivity, for which there are no currently available tools.

Hu Cheng, Ao Li, Andrea Avena-Koenigsberger, Chunfeng Huang, Sharlene Newman

As an alternative to template based brain parcellation in functional connectivity analysis, nearly equal-sized random parcellations are applied to individual subjects multiple times to obtain a pseudo-bootstrap sample of the functional network. As one application, the method was applied on the HCP resting state dataset to identify individuals across scan sessions based on the mean functional connectivity. With a parcellation number of 278 and bootstrap sample size of 400, an accuracy rate of ~90% was achieved by simply finding the maximum correlation of mean functional connectivity of pseudo-bootstrap samples between two scan sessions. 

Dario Englot, Peter Konrad, Monica Jacobs, John Gore, Bassel Abou-Khalil, Victoria Morgan

Seizures in temporal lobe epilepsy (TLE) disturb brain network physiology and lead to brain connectivity disturbances. We used resting-state functional MRI (fMRI) recordings in TLE patients and controls to examine functional connectivity between brainstem ARAS structures and cortical/subcortical regions. ARAS connectivity was significantly lower in TLE patients than controls, with largest connectivity decreases noted in neocortical regions ipsilateral to the epileptogenic zone. Diminished ARAS connectivity was related to seizure frequency and neuropsychological impairments. Functional connectivity analysis of small brainstem structures using fMRI is feasible and may provide important information regarding mechanisms of disease in neurological disorders.

Sue-Jin Lin, Tobias Baumeister, Alex MacKay, Irene Vavasour, David Li, Martin McKeown

Resting state fMRI (rsfMRI) has been widely used to study brain function. Numerous informative features derived from rsfMRI data have been proposed, such as graphical metrics and dynamic connectivity, but their robustness is uncertain. In order to verify their reproducibility, we acquired rsfMRI three times for 11 subjects and calculated 7 graphical measures and 7 dynamic network features. None of the measures showed significant differences among the three rsfMRI sessions. Therefore, we concluded that graphical measures and dynamic network features in rsfMRI are at least robust to inter-trial variability, which should ameliorate uncertainties when applying them to clinical research.   

Xuan Wei, Jiajie Chen, Qiang Li, Wei Wang

Purpose Our research aims to research abstinence and methadone maintenance treatment, to reveal which abstinence way is better and to compare their cue-reactivity in heroin-dependent individuals.

Materials and Methods 24 heroin-dependent patients under abstinence,19 heroin-dependent patients under MMT and 20 healthy volunteers were recruited. The functional images were acquired by using a spin-echo EPI.

Results MMT group brain regions which had differences in cue-reactivity intensity were significantly positive correlation with craving changes, and abstinence group did not exist. Discussion and Conclusion This study showed that abstinence is more advantageous than MMT to reduce heroin addiction in drug cue-reactivity.

Nicole Yuen, Jean Chen

This study examines the frequency dependence of functional connectivity patterns as measured using resting-state fMRI (rs-fMRI). We decompose the rs-fMRI signal into its intrinsic mode functions (IMFs) using the recently proposed variational mode decomposition (VMD) technique, which provides increased frequency precision and reduced modal mixing than previous methods. We show that many functional connectivity patterns can only be seen in a certain frequency range, contrasting previous findings. We concluded that the correlation patterns are frequency dependent and are more prominent and consistent in the lower frequency range.

Kay Jann, Danny Wang

While dynamic functional connectivity (dynFC) provides an estimate of the information transfer between brain network nodes, the signal dynamics at each node represents the local information processing. Here we assessed the relation between dynFC within the default mode network and the complexity/regularity of fMRI signal of network nodes.  We found that a more complex and thus less predictable signal in a node allows for a more dynamic connectivity and hence a richer repertoire of different FC states.

Li Jiyuan, Song Yunlong, Shao Yongcong, Pan Zhibin, Wu Yao, Zhou Lu

There are fifteen health indibiduals recruited in order To explore the changes of functional connectivity in vmPFC with tDCS stimuli after 36 hours sleep deprivation. Colleceting resting-state fMRI data under the tDCS stimuli and sham stimuli conditions. Using the vmPFC as the seed region,and then the time courses of all brain voxels were correlated separately with the mean time course generated from the ROI by Pearson cross-correlation. Finally, we found that  tDCS can effectively mediate the dysfunction of brain connectivity.

Tung-Lin Wu, Jennifer Watchmaker, Li Min Chen, Adam Anderson, Zhaohua Ding, John Gore

In order to further elucidate the biophysical origins of spatio-temporal correlation tensors and validate the possibility of detecting BOLD signals in white matter, we acquired resting-state fMRI in volunteers breathing alternately room air and CO₂ enriched air to induce a hypercapnic-normoxic change in CBF and CBV. Our hypercapnic respiratory challenge experiments suggest that spatio-temporal correlations in white matter may be driven by local hemodynamic effects, consistent with BOLD effects instead of other potential mechanisms. Our results also imply and support our previous observation that BOLD signals in white matter can be reliably detected, and resting-state correlations between voxels are anisotropic. 

Qasim Bukhari, Aileen Schroeter, Markus Rudin

Dynamic functional connectivity (dFC) analysis has gained considerable interest in the past years. The goal of this technique is to estimate the temporal changes of resting state functional connectivity networks and get insights into brain pathologies by analyzing these dynamic patterns. dFC uses functional connectivity correlations as a means to understand the brain functional principle. Dynamic Causal Modeling (DCM) has been widely used in the neuroimaging community to estimate the effective connectivity by fitting a neuronal model to the observed fMRI data. Stochastic DCM together with Bayesian Model Comparison applied to resting state fMRI data results in the selection of the most plausible neuronal model explaining the observed data. The input to these model estimation methods are the full length time series extracted from the regions of interest of mouse resting state fMRI data, neglecting the temporal evolution of the model parameters. In this work we combine the two approaches by estimating the temporal changes in the effective connectivity as derived from DCM.

Garth Thompson, Basavaraju Sanganahalli, Keeley Baker, Justus Verhagen, Gordon Shepherd, Fahmeed Hyder

Are coordinated activations of the brain during sensory stimulation linked to the synchronized activations or “functional connectivity” observed with resting state fMRI? We recorded odor-stimulation fMRI and resting state fMRI in the rat olfactory bulb’s glomerular sheet. Glomerular activations due to three odors were compared to spontaneous fluctuations organized as twenty-two independent component networks. Networks correlated with activation in an odor-specific manner. We reconstructed approximations of activation which retained odor specificity for two of three odors, despite being constructed from resting state data. Our results suggest a function for synchronized resting oscillations in reinforcing stimulation-specific responses.

Ashish Kaul Sahib, Michael Erb, Klaus Scheffler, Thomas Ethofer, Niels Focke

To assess the impact of repetition time (TR) and window size on the temporal features of BOLD functional connectivity (FC) using a sliding window approach in event-related fMRI. in addition, test the feasibility of this approach in epilepsy. We calculated the functional connectivity degree (FCD) by counting the total number of connections of a given voxel above a predefined threshold based on Pearson correlation. In summary, we showed that dynamic FCD transients are better detectable with sub-second TR than conventional TR, indicating a potential to study the temporal characteristics of interictal epileptiform discharges and seizures in epilepsy patients.

Ilaria Suprano, Chantal Delon-Martin, Gabriel Kocevar, Claudio Stamile, Salem Hannoun , Pierre Fourneret, Olivier Revol, Fanny Nusbaum, Dominique Sappey-Marinier

High Potential Children diagnosis remains unclear. We proposed to examine 56 children with a resting state fMRI study. The profile of network topology was explored in two different groups of HP estimating the hub disruption index (k). A disruption of the order of importance of specific nodes in both the HP groups was found with a stronger reorganization in heterogeneous group. This results may offer a confirm of the different psychiatric characteristics that exist between the HP profiles. The sensitivity of graph metrics based on rs-fMRI was demonstrated to be very helpful to provide a better characterization of HP children.  

Wenfeng Li, Hongwei Wen, Yun Peng, Hongbin Li, Yang Wen, Hua Cheng, Yang Fan, Huiguang He, Yue Liu

It is reported that OSAS may cause cognitive function disorder of children due to chronic hypoxia for a long time[1]. However, it is not clear whether there are any structural changes of cerebral regions, e.g. white matter (WM). Diffusion kurtosis imaging is now widely used in the detection of cortical structural changes across kinds of diseases. In the present study, DKI is used to investigate microstructural changes of WM in OSAS children compared with normal healthy controls.

Stefano Tambalo, Giulia Scuppa, Carlo Nicolini, Cecile Bordier, Angelo Bifone

Modular organization of resting state functional connectivity has been demonstrated in human studies using graph theoretical approaches. Various methods, characterized by different resolutions, have enabled the investigation of the functional connectivity structure of the human brain at different scales. Here, we extend these approaches to the study of resting state connectivity in the rat, and demonstrate for the first time the existence of multi-scale, functionally segregated modules in this species.

Esteban Oyarzabal, SungHo Lee, Manasmita Das, Sheng Song, Yen-Yu Ian Shih

Chronic neuroinflammation, present in most neuropathologies, has long-term consequences on neurocircuit connectivity synchrony and strength.  By implementing multi-modal techniques to quantify neuroinflammation, we found a strong association linking the intensity of neuroinflammation with depressed functional connectivity.  We partly attribute these changes to neurodegeneration and the loss of central NE.

Weixiong Fan, Xiaofeng Chen, Fengyan Cheng, Yabao Cheng, Tai Xu, Guijin Li, Xiaolei Zhu, Shuai Li

The aim of this study was to explore the different subtypes and immunohistochemical expression  of breast cancer in improved multi-parametric MR imaging. By introducing the free breathing of ultrafast temporal resolution dynamic VIBE (TWIST-VIBE) and readout segmentation of long variable echo-trains (RESOLVE) techniques, quantitative pharmacokinetic (PK), semi-quantitative DCE-MRI based on curve of time concentration and diffusion parameters were extracted to analyze it. The results show that significant differences in multi parametric parameters Kep and rADC among the different subtypes of Breast cancer. Those parameters were hopeful to be a non-invasive measurement for assessing the subtypes and the biology, histological features of breast cancer.

Tuija Keinänen, Seppo Rytky, Vesa Korhonen, Juha Nikkinen, Osmo Tervonen, Matias Palva, Vesa Kiviniemi

Resting-state networks (RSN) functional connectivity has shown to be temporally dynamic in the brain. Also the correlations between infra slow fluctuations in electroencephalography (EEG) and blood oxygen level-dependent signal have shown dynamic variability over time. Here, we used simultaneous EEG-fMRI with ultra-fast magnetic resonance encephalography to study the link between the variations of these correlations and variations in RSN functional connectivity. The results suggest that the correlation strength is markedly linked to the strength of underlying functional connectivity. This leads to low correlations when averaged over a long period, high momentary synchrony can be reached due to intrinsic RSN dynamics.

Pui Wai Chiu, Hui Zhang, Issac Ip, Savio Wai Ho Wong, Tianyin Liu, Gloria Hoi Yan Wong, Queenie Chan, Kelvin Kai Wing Yau, Leung Wing Chu, Henry Ka Fung Mak

fMRI can indirectly measure brain activity, but the biochemical underpinnings of the BOLD changes are still unknown. Nevertheless, ¹H-MRS can bridge such gap by measuring Glx [summation of glutamate (Glu) and glutamine (Gln)], where Glu is one of the mediators of neurovascular coupling. In this study, we aim to elucidate the complex relationship between attention control (numerical Stroop) and its associated neurochemical changes by combining the biochemical information from task-based fMRI and ¹H-MRS. Our result showed that the anterior cingulate cortex was positively correlated with Glx. This is the first study providing neurochemical explanation of the BOLD change during attention control task.

Kevin Tsai, Hsin-Ju Lee, Wen-Jui Kuo, Jo-Fu Lotus Lin, Fa-Hsuan Lin

Non-stationary EEG noise from simultaneous fMRI-EEG acquisition could be conventionally removed by optimal basis selection and followed by a low-pass filtering. An empirical model decomposition (EMD) method was applied to partially remove non-stationary EEG noise from simultaneous fMRI-EEG acquisition. Our results suggested that EMD method could reveal similar auditory evoked potential with optimal basis selection and low-pass filtering without prior knowledge or cut-off frequency, thus preserving high frequency signal not empirically related to the non-stationary noise. This EMD method allows us to investigate human brain high frequency EEG oscillation in the simultaneous fMRI-EEG measurement.

Shuoyue Zhang, Bruno Riemenschneider, Maxim Zaitsev, Jürgen Hennig, Pierre LeVan

Simultaneous acquisition of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) is extensively applied for brain mapping due to the high temporal resolution of EEG and high spatial resolution of fMRI. But gradient artifacts on the EEG cannot be optimally corrected in the presence of abrupt head movements. In this work, we demonstrate a method to model motion-related gradient artifacts. Thus we obtain not only an improvement in gradient artifact correction, but also infer motion information directly from the EEG.

Zhengge Wang, Bing Zhang, Bin Zhu

Several recent studies have reported a correlation between regional glutamate concentration and BOLD activation. In this study, we combined resting-state fMRI and MRS to investigate whether this association maintain in spontaneous brain activity in the thalamus. Significant positive correlation was found between glutamate concentration and the ALFF and ReHo in left thalamus; negative correlation between glutamate and DC in left thalamus. Furthermore, the ALFF of left primary motor cortex and bilateral auditory cortex were affected by left thalamus glutamate. This provides insight into better understanding the neuronal and biochemical mechanisms of thalamus function.

Li Zheng, Jingwei Sheng, Tianyi Qian, Thomas Beck, Jia-hong Gao

In patients with intractable epilepsy, anomalous cortical organization could be observed and pre-surgical planning involving the localization of cortical language areas is critical. As a prospective study, we compared language localization using functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG) with advanced source estimate method in 18 volunteers. Group analysis results showed something similar or discordant between fMRI and MEG activation. It is consider that fMRI technique combined MEG can used for the preoperative localization and postoperative functional evaluation in the future.

Alex T. L. Leong, Russell W. Chan, Xunda Wang, Celia M. Dong, Leon C. Ho, Ed X. Wu

Top-down/descending control is a critical stage in sensory processing that underlies numerous cognitive processes. Recent studies uncovered the prevalence of converging long-range networks across multiple sensory modalities as anatomical substrates that likely mediate sensory top-down control. Using an optogenetic fMRI technique that we recently developed to examine patterns of large-scale brain-wide interactions mediated by the somatosensory thalamo-cortical network, we demonstrated that propagating low frequency activity (~1Hz) underlying such interactions enhanced visual responses in the superior colliculus. This work presents a new approach to investigate the functional roles of top-down control and their underlying brain mechanisms. 

Mark Chiew, Jostein Holmgren, Nadine Graedel, Dean Fido, Catherine Warnaby, Karla Miller

We propose a method for correcting gradient artefacts in simultaneous EEG-FMRI that are variable from shot-to-shot, where artefacts cannot be identified via averaging. The artefact model is extracted from a data-driven decomposition that identifies the signal contributions which show geometric variation matching that of the trajectory rotation model. We show that this correction, applied to a rotating EPI trajectory, works just as well as standard approaches applied to conventionally sampled (non-rotating) EPI data. This will allow the use of more flexible sampling approaches in simultaneous EEG/FMRI that facilitate highly accelerated dynamic image reconstruction.

Irene Neuner, Ravichandran Rajkumar, Praveen Sripad, Christine Wyss, Jörg Mauler, Lutz Tellmann, Elena Rota Kops, Jürgen Scheins, Markus Lang, Frank Boers, Christoph Lerche, Johannes Ermert, Bernd Neumaier, Jürgen Dammers, Karl-Josef Langen, Hans Herzog, Wolfram Kawohl, N Jon Shah

How quickly does the human brain switch back from a task mode to the resting state condition? This question is addressed in a small sample of healthy volunteers employing a simultaneous trimodal MR-flumazenil-PET-EEG approach at 3T. Based on the fMRI results, we observe an increase in ReHo - a measure of local connectivity - coupled with a slight decrease in the binding potential of [¹¹C] Flumazenil in the PCC which is a major hub of the default mode network; this indicates a change of the GABA-ergic driven inhibitory tonus. This is accompanied with changes in the alpha band over parietal electrodes.

Lisa Krishnamurthy, Venkatagiri Krishnamurthy, Dina Schwam, Daphne Greenberg, Robin Morris

Previous reports have shown that resting concentrations of gamma-amino butyric acid (GABA) will predict resting state Functional Connectivity (rsFC) measures as well as amplitude of task activation. The goal of this study is to model how the neurochemical profile interplays with the connectivity underlying the decoding and fluency components of the reading circuit. Our model is in support of recent task-based fMRI observations, but goes beyond by interrogating the underlying networks that support the behavior, and combining that information with the neurochemistry that characterize the trait. These preliminary results of combining MRS and rsFC with neuropsychological measures are promising, and will help identify the underlying dysfunction in struggling adult readers’ brain circuitry.

Weina Wang, Youjin Zhao, Xinyu Hu, Qiyong Gong

Evidence of structural and resting-state functional brain abnormalities in MDD has been inconsistent. We conducted the first multimodal meta-analysis of voxel-based morphometry (VBM) and amplitude of low-frequency fluctuation (ALFF) studies in first-episode drug-naïve MDD patients. 15 VBM data setsand 11 ALFF data sets were included. A multimodal meta-analysis was used to highlight brain regions with both structural and functional abnormalities. The multimodal meta-analysis identified conjoint structural and functional differences in the left lateral orbitofrontal cortex and right supplementary motor area.  Dissociated anatomical and functional brain abnormalities in MDD were also observed. Meta-analysis revealed in MDD a complex pattern of conjoint and dissociated structural and functional brain abnormalities in brain regions involved in cognition and emotional processing.

Jing Xu, Tianyi Qian, Thomas Beck, Jia-Hong Gao

Multimodal functional neuroimaging by combining fMRI and EEG has been studied to achieve high-resolution reconstruction of the spatiotemporal cortical current density (CCD) distribution. Although fMRI-constrained EEG/MEG source imaging can enhance spatiotemporal resolution of functional neuroimaging, it has been reported that hard fMRI constraint can result in misidentification of neuronal sources if mismatches exist between fMRI activations and EEG/MEG sources. In this study, we propose a new method modified fMRI-weighted minimum-norm estimation (mfMNE) to solve the problem of fMRI–EEG integrated source imaging. This method may be a promising option for solving the mismatches between fMRI and EEG/MEG in the fMRI-constrained EEG/MEG source imaging.

Mark Lowe, Wanyong Shin, Balu Krishnan, Lael Stone

Recent reports indicate that cerebrovascular reactivity (CR) may be impaired in multiple sclerosis (MS). Here we report initial studies to use simultaneous measurements of electroencephalography (EEG) and BOLD during performance of a motor task. Using EEG-derived predictors of BOLD response, we show that, while EEG robustly predicts the amplitude of the BOLD signal in healthy control subjects, the estimation is very poor in MS patients. This could be direct evidence of cerebrovascular decoupling of the BOLD signal in MS.

Xuan Niu, Yuchen Zhang, Qiuli Zhang, Haining Li, Zhuonan Wang, Yingxiang Sun, Lijun Bai, Ming Zhang

This paper presents an original research to investigate the underlying neural mechanism on analgesia at ipsi- or contra-lateral acupuncture with capsaicin-induced allodynia on human body. Our findings further suggested that DMN participants in the modulation of spatial-oriented attention on placebo analgesia as a mechanism underlying the degree to which treatment side corresponding to the pain. Notably, disruptions of the DMN may account for the cognitive and behavioral impairments in chronic pain patients. In addition, it may possibly reflect individual variation in placebo response, thus, as a valuable neural biomarker to predict clinical curative effect in acupuncture treatment.

Yuan Wang, Dongyuan Cao, Bethany Remeniuk, David Seminowicz, Ming Zhang

To testify the hypothesis of morphometric and functional alterations of patients with idiopathic trigeminal neuralgia (ITN), we displayed gray matter volume (GMV) reductions in the anterior and middle cingulate cortex (ACC and MCC), insula, and several regions of temporal lobe. Additionally, enhanced functional connectivity was revealed between right insula and ACC, medial prefrontal cortex, posterior cingulate cortex (PCC), and dorsal lateral prefrontal cortex in ITN patients. Furthermore, GMV of left inferior temporal gyrus negatively correlated with pain intensity and disease duration in patients, and connectivity of right insula-ACC was negatively associated with pain scores, depression, and anxiety ratings, respectively.

Qian Sun, Guan-Qun Chen, Yu Ying, Yu-Chuan Hu, Lin-Feng Yan, Xin Zhang, Yang Yang, Wen Wang, Ying Han, Guang-Bin Cui

Researchers and clinicians interested in neuroimaging and type 2 diabetes mellitus without cognitive impairment, with a particular interest in diffusion tensor imaging (DTI) and resting state functional magnetic resonance imaging (rs-fMRI) 

Makoto Uji, Ross Wilson, Susan Francis, Stephen Mayhew, Karen Mullinger

We establish a methodology for optimal combination of simultaneous EEG recording with sparse multiband fMRI that preserves high resolution, whole brain fMRI coverage with broad-band EEG signal measurement uncorrupted by MR gradient artefacts. We demonstrate the ability of this approach to record gamma frequency (>50Hz) EEG signals, that are usually obscured during continuous fMRI data acquisition. In a novel application to a motor task we observe a positive correlation between gamma and BOLD responses, supporting and extending previous findings concerning the coupling between neural and haemodynamic measures of brain activity.

Eleanor Barratt, George O'Neill, Rosa Sanchez-Panchuelo, Matthew Brookes, Susan Francis

Sensorimotor mapping allows separation of the brain’s representation of individual digits. This is possible using functional magnetic resonance imaging (fMRI), but is more challenging in magnetoencephalography (MEG) where it has been demonstrated by mapping evoked responses. Here, we use ultra-high field (7T) fMRI to map digits in a finger-tapping experiment, and contrast our findings to equivalent results showing the spatial signatures of beta band oscillatory responses measured in MEG. We show that the MEG beta rebound can be mapped topographically.

Chung-Ki Wong, Vadim Zotev, Raquel Phillips, Masaya Misaki, Jerzy Bodurka

In EEG-fMRI, EEG electrodes record head motions with a high temporal resolution (EEG-motion-sensor), which can be utilized for retrospective slice-by-slice fMRI motion correction. EEG motion components derived from independent component (IC) analysis were automatically identified by the common features observed in the IC mean power spectral density, spatial projection topographic map, and signal contribution. For real-time application of the EEG-motion-sensor, pre-trained models are desirable for faster classification. We used convolutional neural network to evaluate performance of motion-IC classification model. High speed and classification accuracy were achieved on a large EEG-fMRI dataset, suggesting the possibility of real-time EEG-motion-sensor applications for fMRI.

Chung-Ki Wong, Qingfei Luo, Vadim Zotev, Raquel Phillips, Jerzy Bodurka

In simultaneous EEG-fMRI, the period of cardioballistic artifact (BCG) in EEG is required for the artifact removal. Recording the electrocardiogram (ECG) waveform during fMRI is difficult, often causing inaccurate period detection. Since the BCG artifact waveform in EEG-fMRI is relatively invariable compared to the ECG waveform, we propose a multiple-scale peak-detection algorithm to determine directly the BCG period from EEG-fMRI data. The algorithm achieves a high detection accuracy of the BCG artifact occurrence on a large EEG-fMRI dataset without using the ECG waveforms, virtually eliminating the need for ECG for BCG artifact removal.

Christin Sander, John Arsenault, Bruce Rosen, Wim Vanduffel, Joseph Mandeville

In this study, deep brain stimulation with chronically implanted electrodes in the unilateral ventral tegmental area of a monkey was performed. The purpose was to determine stimulation paradigms for a range of inter-stimulation intervals that would enable the simultaneous observation of brain activity using fMRI and endogenous dopamine release using [¹¹C]raclopride-PET. While long inter-stimulation intervals produced a unilateral focal CBV response in the striatum but no change in [¹¹C]raclopride binding, short intervals produced a more widespread CBV response and displacement of [¹¹C]raclopride. This study shows the effect of stimulation parameters on brain activity, neurotransmitter release and its limits of detectability.

Martin Tik, Michael Woletz, Lucia Navarro de Lara, Ronald Sladky, André Hoffmann, Allan Hummer, Nicole Geissberger, Christian Windischberger

In this work we show the feasibility of a novel concurrent TMS/fMRI setup based on two multi-channel receive arrays that allows for whole brain fMRI data acquisition during brain stimulation. We show that stimulation at frequencies of 1 and 10Hz, respectively, leads to distinct changes in BOLD signal. We also report increased TMS-related network effects with higher stimulation. This validity check sets the frame for efficacy studies investigating the TMS stimulation of cortical areas for modulating complex brain networks.