Yu Xu¹, Tingting He², Haiming Wang², Xiao Yu¹, Boyi Qu², Ssu-Ju Li³, and Hsin-Yi Lai^4
1Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China, ²College of Biomedical Engineering & Instrument Science, Zhejiang University. Interdisciplinary Institute of Neuroscience and Technology, Zhejiang University, Hangzhou, China, ³Department of Biomedical Engineering, National Yang Ming University, No. 155, Section 2, Linong Street, Taipei, 112, Taiwan, ROC. Department of Biomedical Engineering, National Yang Ming Chiao Tung University, No. 1001 Ta-Hsueh Rd., Hsinchu, 300, Taiwan, ROC, Taiwan, China, ⁴College of Biomedical Engineering & Instrument Science, Zhejiang University. Department of Neurology of the Second Affiliated Hospital, Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University. Department of Neurology of Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China

Focused ultrasound (FUS) has shown its unique advantages in the field of non-invasive neuromodulation. The dorsolateral prefrontal cortex (DLPFC) is a key node in brain networks involved in cognitive, emotional and sensory processing. Here we evaluated the immediate and latency effects of DLPFC-FUS by functional magnetic resonance imaging (fMRI). The results showed that DLPFC-FUS induced a 3% increase in positive BOLD signal, and decreased FCs in bilateral primary and secondary visual cortices, supported by visual stimuli-evoked BOLD change. Moreover, FCs significantly decreased in left thalamus at 5-min post-FUS and in bilateral anterior cingulate cortex (ACC) at 30-min post-FUS. These results may help to elucidate the effect of FUS neuromodulation.

Yu-Chieh Hung¹, Yi-Cheng Wang¹, Hao-Li Liu², and Hsu-Hsia Peng^1
1Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan, ²Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan

Focused ultrasound (FUS) has been considered as a noninvasive neuromodulation method. In addition to evaluate the functional connectivity (FC) by an average of BOLD signals across the whole scan, a dynamic FC (dFC) can help to comprehend the instant alternation of FC. We aimed to investigate the alterations of dFC after FUS-neuromodulation at VPM/VPL in a normal rat model.

We used k-means and dynamic network analyses to evaluate changes of dFC at Pre-FUS, Sham, 35-min, 3-hr, and 3-day for rats with FUS sonication at VPM/VPL. We found an instant effect of FUS-neuromodulation (35-min) and a recovering trend in 3-day.

Zengmin Li¹, Dilsher Athwal¹, and Kai-Hsiang Chuang^1,2
1Queensland Brain Institute, The University of Queensland, St Lucia, Australia, ²Centre for Advance Imaging, The University of Queensland, St Lucia, Australia

• Collective influence (CI) analysis provided optimal ranking list of nodes which fastest reduced the giant component of the resting-state networks (RSNs).
• Post-learning inhibition of brain regions which were top CI nodes caused retrograde amnesia in the probe test eight days after spatial learning task.
• Data-driven approaches were used to explore the role of RSNs in memory consolidation.

Evan Houldin¹, Zengmin Li¹, and Kai-Hsiang Chuang^1
1University of Queensland, Brisbane, Australia

Recent evidence indicates a putative mouse homologue of the human triple-network model, for which a salience network (SN) actively engages either internally-oriented default mode network (DMN) or externally-oriented central executive network (CEN). The interaction amongst these homologues has yet to be validated. This study probed SN responses to DMN inhibition in mice, during functional magnetic resonance imaging. We found that SN radically adjusts its connectivity profile with triple-network components, depending on which DMN hub is inhibited. This indicates that triple-network must be considered holistically, with SN serving an important role in overall triple-network connectivity.

Chengwen Liu¹, Chen Liu², Li Zhaoping³, and Peng Zhang^2
1Second Xiangya Hospital,Central South University, Changsha, China, ²Institute of Biophysics, Chinese Academy of Sciences, Beijing, China, ³University of T ̈ubingen, Max Planck Institute for Biological Cybernetics, T ̈ubingen, Germany

Using a slab-selective VASO sequence at 7 T, we investigate cortical depth-dependent CBV fMRI activity to orientation-defined saliency stimuli in early visual and parietal cortices of the human brain. Results show that the fMRI response of salient foreground bars is strongest in the superficial depth of V1, and peaks in the middle cortical depth of V2/V3 and IPS. These findings support the hypothesis that bottom-up saliency is initially created by iso-feature suppressions through lateral connections in V1 superficial layers, and then feedforward to parietal cortex to generate the attention priority map.

SoHyun Han^1,2, Seulgi Eun^1,2, HyungJoon Cho³, Kâmil Uludaǧ^1,2, and Seong-Gi Kim^1,2
1Center for Neuroscience Imaging Research, Suwon, Korea, Republic of, ²Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Korea, Republic of, ³Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan, Korea, Republic of

Both spatial specificity and sensitivity are important for high spatial resolution fMRI. In this study, we applied a filter designed based on the ΔR₂^*/ΔR₂ ratio to enhance both the sensitivity and specificity of the BOLD signal using SAGE-EPI sequence. fMRI experiments during fist-clenching with touching with 0.8 mm isotropic resolution were performed and we directly compared the layer profile of SAGE-BOLD with that of GE- and SE-BOLD in the primary sensory and motor cortices. Vessel-size tuned SAGE-BOLD fMRI provided enhanced laminar specificity and sensitivity in the gray matter region.

Seulgi Eun^1,2,3, SoHyun Han^1,2, Kâmil Uludaǧ^1,2,4, and Seong-Gi Kim^1,2
1Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, Korea, Republic of, ²Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Korea, Republic of, ³Department of Biomedical Engineering, Kyung Hee University, Yongin, Korea, Republic of, ⁴Techna Institute & Koerner Scientist in MR Imaging, University Health Network, Toronto, ON, Canada

Limitations of the several developed laminar fMRI acquisition methods and pial and intra-cortical ascending vein contamination of the gradient-echo (GE) restrict the neural specificity of the depth profiles. Preserving the advantage of high sensitivity of the GE-EPI sequence, we propose a simple and intuitive model to normalize laminar BOLD with breath holding. Our normalization method increased specificity of the BOLD activation map and emphasized laminar BOLD signal changes in gray matter regions by suppressing signal changes from CSF. This approach takes into account the different vascular sensitivity across layers but may not fully account for the draining vein contamination.

Fatemeh Taheriyan¹, Zahrah Fazal¹, Kevin Klein Gunnewiek¹, Jenni Schulz¹, Jose Marques¹, and David G Norris^1
1Radboud University, Donders Institute, Nijmegen, Netherlands

Arterial blood contrast  increase the cerebral blood volume contribution to brain activation studies by suppressing  grey matter signal using on-resonance magnetisation transfer. An increase in CBV will lead to an increase in signal, which is then complementary to BOLD. We performed multi-echo resting state fMRI in a group of 16 subjects and compared the results at TE=28ms with MT-off (standard BOLD) and TE=6.9 MT-on (ABC). Z-scores were higher for standard BOLD at all TEs but with higher variance in the z-score value. Dual regression results never the less showed high similarity activation maps for standard resting state networks.

Xiaoyun Liang^1,2, Chun-Hung Yeh^3,4, and Peter J. Anderson^1,5
1Victorian Infant Brain Study (VIBeS), Murdoch Children's Research Institute, Melbourne, Australia, ²Florey Department of Neuroscience and Mental Health, University of Melbourne, Heidelberg, Australia, ³Institute for Radiological Research, Chang Gung University and Chang Gung Memorial Hospital, Taoyuan, Taiwan, ⁴Department of Psychiatry, Chang Gung Memorial Hospital, Taoyuan, Taiwan, ⁵Turner Institute for Brain and Mental Health, Monash University, Clayton, Australia

In this study, we applied a method that integrates dynamic functional connectivity using the multiplex network approach to enhance the sensitivity to subtle alterations of functional connectivity on participants subject to PAE. Our results demonstrated its capability in characterizing subtle brain network changes in children with low-moderate PAE. The lower  values of the PAE T1-T3 group indicates that the information processing speed could have been compromised due to PAE. In line with literature, the distinct findings between male and female groups revealed that PAE may induce gender-dependent brain disruptions and males are more susceptible to PAE.

Yanting Liu¹, Sihui Zhao¹, Yanan Gao¹, Hui Steve^2,3, Mikkelsen Mark^2,3, A.E.Edden Richard^2,3, Chen Zhang⁴, and Bing Yu^1
1China Medical University, Shenyang, China, China, ²Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA, Baltimore, MD, United States, ³F. M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA, Baltimore, MD, United States, ⁴MR Scientific Marketing, Siemens Healthineers, Beijing, China

We carried investigation to explore the relationship of GABA level of occipital lobe on topological and organizational properties of the entire brain using Hadamard Encoding and Reconstruction of Mega-Edited Spectroscopy (HERMES) method. Synchronous EEG-MRS data were obtained from forty healthy volunteers. GABA+ level and  the global topological topological characters of the EEG functional connectivity network were calculated. The results demonstrate that the GABA+ level of the occipital lobe showed a significant negative correlation with the small world index of EEG functional connectivity network in the EEG α band.

Himanshu Singh¹, S Senthil Kumaran¹, and Ankeeta A^1
1Department of NMR, All India Institute of Medical Sciences, Delhi, India

Auditory working memory is associated with sound pressure level for perception of information. However, its acoustic characteristics that represent information is not well understood. We used 1-back and 2-back auditory working memory tasks and acoustic characteristics (including pure tone assessment, audiometric threshold) to understand cognitive connectome with respect to frequency. This study explores the association of frequency characteristics underlying semantics necessary to understand auditory cognition. 

Paul COUDERT^1,2, Pierre Antoine ELIAT^3,4, Yann SERRAND³, Nicolas COQUERY³, Gwenole TANGUY^1,2, Stéphane LAURENT^1,5, Hervé SAINT-JALMES^4,6, David VAL LAILLET³, and Benoit GODEY^1,2
1ENT, CHU of Rennes, Rennes, France, ²INSERM, MediCIS, University Rennes 1, Rennes, France, ³INRAE, NuMeCan 1341, University Rennes 1, Rennes, France, ⁴PRISM, CNRS, INSERM, BIOSIT, Univ Rennes, Rennes, France, ⁵School of audioprosthesis of Fougères, Université Rennes 1, Fougères, France, ⁶INSERM, LTSI UMR 1099, University Rennes 1, Rennes, France

This work presents a functional MRI model to study the activation of central auditory pathways in a pig model at 1.5T. The conventional pig is a good model due to its anatomical similarity to humans, and therefore could be relevant to study and understand brain responses to auditory stimulations.

Xin Xu¹, Han Lai¹, Cheng Yang¹, John Sweeney¹, and Qiyong Gong^1
1Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan Uinversity, Chengdu, China

The neural correlations that characterize hopelessness may help identify brain mechanisms and individuals at risk of depression and suicide. Here, we examined the functional connectivity (FC) patterns of resting state associated with hopelessness in healthy later adolescents and young adults by using CPM. We found that the level of hopelessness was negatively correlated with the FC between the right MTG and the bilateral PoG and PrG, as well as the FC between the right cerebellum VI and the left thalamus. The finding suggested that cortical-cerebellum networks underlying negative future expectation processing characterized hopelessness.

Shin-Lei Peng¹, Lok Wang Lauren Chu¹, and Feng-Yi Su^2
1Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung, Taiwan, China Medical University, Taichung, Taiwan, ²Department of Medical Imaging, China Medical University Hospital, Taichung, Taiwan

The main aim of this study was to characterize the acute effect of caffeine on cerebral hemodynamic responses in participants with different caffeine consumption habits. The non-habitual group exhibited a larger degree of vasoconstriction and thus diminished the ability to dilate upon stimulation. As the vessel dilation ability has been considered as a covariate to explain variabilities in fMRI signals, our results may suggest that the suppressed BOLD response to a visual stimulation in low-caffeine-level users could be partially attributed to the decreased vascular reactivity altered by the baseline perfusion.

Hui Zhang^1,2, Peng Cao¹, Henry K.F. Mak^2,3, and Edward S. Hui^4
1Diagnostic Radiology, The University of Hong Kong, Pokfulam, Hong Kong, ²Alzheimer's Disease Research Network, The University of Hong Kong, Pokfulam, Hong Kong, ³The University of Hong Kong, Pokfulam, Hong Kong, ⁴Rehabilitation Sciences, The Hong Kong Polytechnic University, Hung Hom, Hong Kong

We aim to investigate the effect of aging, sex, years of education, total cognition, and the disease burden of small vessel disease, the most cause of vascular dementia, on not only the coupling of the entire brain, but also the coupling of intra and inter-functional networks. We have demonstrated varying effect of sex, years of education and total cognition on global and intra/inter-network couplings.