Tzu-Hao Harry Chao¹, Li-Ming Hsu¹, Martin MacKinnon¹, and Yen-Yu Shih^1
1University of North Carolina at Chapel Hill, Chapel Hill, NC, United States

This study establishes a novel MR-compatible multi-channel fiber-photometry platform and demonstrates 1) photometry-CBV measured in PrL and Cg co-fluctuate with global DMN signal derived from CBV-fMRI, 2) significantly enhanced 0.6-0.8 Hz GCaMP power in PrL, Cg, and RSC, but not AI, between two DMN states, 3) significantly enhanced 0.25-0.45 Hz GCaMP power in PrL, Cg and RSC precedes DMN activation peak by 3-5 s, but not AI, and 4) significantly enhanced 0.6-0.8 Hz GCaMP power in AI precedes DMN deactivation valley by 11 s.

Gijs Jurjen Heij¹, Thoralf Niendorf^1,2, and Henning Matthias Reimann^1
1Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrück-Center for Molecular Medicine, Berlin, Germany, ²Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany

Despite millions of people suffering from chronic pain, clinicians still rely on self-reports for the assessment of pain. In attempts to identify objective biomarkers, fMRI studies have revealed an assembly of regions that consistently activates in response to noxious stimuli, but also to non-noxious equally salient stimuli. Since most studies have been performed at 3T or lower, higher field strengths might be able to differentiate pain from saliency. As a first step, we aimed to identify the pain-matrix at ultrahigh fields using an ON/OFF heat stimulation paradigm and show here that the regions associated with the pain-matrix could be identified. 

Hui Zhang^1,2, Pui Wai Chiu^1,3, Isaac Ip⁴, Tianyin Liu⁵, Gloria Hoi Yan Wong⁵, You-Qiang Song⁶, Savio Wai Ho Wong⁴, Queenie Chan⁷, Karl Herrup⁸, and Henry Ka Fung Mak^1,2,3
1Department of Diagnostic Radiology, The University of Hong Kong, Hong Kong, Hong Kong, ²Alzheimer's Disease Research Network, Hong Kong, Hong Kong, ³State Key Laboratory of Brain and Cognitive Sciences, Hong Kong, Hong Kong, ⁴Department of Educational Psychology, the Chinese University of Hong Kong, Hong Kong, Hong Kong, ⁵Department of Social Work and Administration, The University of Hong Kong, Hong Kong, Hong Kong, ⁶Department of Biochemistry, The University of Hong Kong, Hong Kong, Hong Kong, ⁷Philips Healthcare, Hong Kong, Hong Kong, ⁸Alzheimer Disease Research Centre, University of Pittsburgh, Pittsburgh, PA, United States

To identify the relationship between the topological properties and glutamate in genetic-related subgroups (ApoE4 carriers and non-ApoE4 carriers), combined resting state fMRI (rs-fMRI) and MRS were applied in this study. Graph theory metrics of subgroups were calculated and compared. In the results, ApoE4 carriers had worse network segregation and integration. However, there was significant correlation between [Glx]_abs in left hippocampus and topological metrics in high-risk group. We postulated that glutamatergic synaptic transmission modulates rs-fMRI activities in ApoE4 carriers.

Daisuke Sawamura^1,2, Ryusuke Suzuki³, Keita Ogawa⁴, Shinya Sakai², Xinnan Li¹, Hiroyuki Hamaguchi¹, and Khin Khin Tha^5,6
1Department of Biomarker Imaging Science, Graduate School of Biomedical Science and Engineering, Hokkaido University, Sapporo, Japan, ²Department of Functioning and Disability, Faculty of Health Sciences, Hokkaido University, Sapporo, Japan, ³Departments of Medical Physics, Hokkaido University Hospital, Sapporo, Japan, ⁴Department of Rehabilitation, Hokkaido University Hospital, Sapporo, Japan, ⁵Department of Diagnostic and Interventional Radiology, Hokkaido University, Sapporo, Japan, ⁶Global Station for Quantum Medical Science and Engineering, Hokkaido University, Sapporo, Japan

Little is known about how neurocognition is modulated upon combined computerized cognitive training (CCT). We developed a combined CCT program designed to improve several cognitive functions simultaneously, and evaluated its effect on neurocognitive performance and functional connectivity (FC) of the brain. The results suggest that the CCT improves not only the targeted functions but also the other aspects of neurocognition via augmentation of transfer effect. The LPFC and fronto-parieto-occipital networks are thought to play role. 

SUJAS BHARDWAJ¹, RAJANIKANT PANDA², SHWETA PRASAD¹, SUNIL KUMAR KHOKHAR³, SNEHA RAY³, ROSE DAWN BHARATH³, and PRAMOD KUMAR PAL^1
1NEUROLOGY, NIMHANS, Bengaluru, India, ²Coma Science Group, Universitè de Liège, Liège, Belgium, ³NI & IR, NIMHANS, Bengaluru, India

We assessed the effect of repetitive transcranial magnetic stimulation (rTMS) on whole brain dynamics using fMRI. MRI was acquired before and after a single session of rTMS in 30 patients of Essential Tremor and 20 age matched healthy controls. Whole brain dynamic synchronization - “metastability”, and propagation of integration - “intrinsic ignition”, were studied in order to assess brain network topological fluctuations following rTMS. Single subject and group wise whole brain metastability, integration and ignition driven integration was found improve with a single session of rTMS.

Xirui Hou¹, Zixuan Lin¹, Peiying Liu¹, Corinne Pettigrew², Anja Soldan², Marilyn Albert², and Hanzhang Lu^1
1The Russell H. Morgan Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States, ²Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States

Cerebral metabolic rate of oxygen (CMRO₂), the rate at which O₂ is consumed in the brain, is thought to be a direct index of energy hemostasis and brain health. Recent studies have suggested that CMRO₂ is elevated but functional connectivity is declined with age. In this work, we demonstrated the diminished default network was associated with aberrant CMRO₂ in older healthy subjects. Network analysis indicated that the increasing amount of CMRO₂ was used to compensate for the inefficiency of degraded networks.

Melanie Morrison¹, Angela Jakary¹, Erin Felton², Schuyler Stoller², Sabine Mueller², and Janine Lupo^1
1Radiology & Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States, ²Department of Pediatrics, University of California San Francisco, San Francisco, CA, United States

While radiation therapy plays an essential role in the management of brain tumor patients, exposure to radiation has been known to lead to declines in neurocognitive performance and vascular injury. As there remains a need for a reliable marker and predictor of patient outcome, this study explores the usefulness of functional connectivity measurements derived from 7T rsfMRI. We found that temporal properties, specifically low-frequency signals of some large-scale brain networks,are associated with more severe cognitive impairment and vascular injury, highlighting the potential benefit of using rsfMRI for treatment planningand prediction of patient outcome after RT.

Xiaowei Han^1,2, Guolin Ma¹, and Lizhi Xie^3
1Department of Radiology, China-Japan Friendship Hospital, Beijing, China, ²Graduate School of Peking Union Medical College, Beijing, China, ³GE Healthcare, MR Research China, Beijing, China

Schizophrenia is a neurodevelopmental psychiatric disorder with unclear etiology and no effective treatment. In this study, we established a new schizophrenia model in rats using early growth response (EGR3) gene transfection which was injected into the hippocampus and dentate gyrus of rats. The model was examined by evaluating the behavioral impact and cerebral alterations of schizophrenia model rats using behavioral phenotyping and resting-state functional magnetic resonance imaging (rs-fMRI). In addition, the efficacy of risperidone therapy was also evaluated in treated group rats. Briefly, we found several regional alterations in the cerebrum, which were consequently partially reversed by risperidone.

Lipeng Ning^1,2 and Yogesh Rathi^1,2
1Brigham and Women's Hospital, Boston, MA, United States, ²Harvard Medical School, Boston, MA, United States

We propose an algorithm to estimate whole-brain effective connectivity measures by integrating structural connectivity matrix between brain regions and resting-state functional MRI data. Our algorithm first uses the Lyapunov inequality from control theory to ensure that the estimated whole-brain dynamic system is stable and physically meaningful. Then, the effective connectivity measure is characterized by a novel conditional causality measure. We applied the proposed algorithm to a public dataset which consisted of healthy controls (n=94), patients with schizophrenia (n=45), bipolar (n=44) and ADHD (n=37). Our results show that the proposed approach provides reliable estimation brain-network features of these brain disorders.

Tamara Vasilkovska¹, Bram Callewaert¹, Somaie Salajeghe¹, Dorian Pustina², Longbin Liu², Mette Skinbjerg², Celia Dominguez², Ignacio Munoz-Sanjuan², Annemie Van der Linden¹, and Marleen Verhoye^1
1Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium, ²CHDI Foundation, Princeton, NJ, United States

Static FC changes in neurodegeneration can indicate underlining neural mechanism pathology present in pre-manifest disease stage. In addition to the spatial FC component, quasi-periodic patterns (QPPs) implement spatiotemporal information of neural activity, allowing integrated assessment of possible initial changes in large-scale brain dynamics. We measured Low Frequency (LF) BOLD changes using rsfMRI in Q175 HD mouse model at 3 and 12 months of age. Results indicate decreased FC between specific regions in heterozygous compared to wild-type mice at 12 months. Both at 3 and 12 months, additional QPPs are present in the heterozygous group, deviating from the wild type group.

Russell W Chan¹, Mazen Asaad², Bradley J Edelman¹, Hyun Joo Lee¹, Hillel Adesnik³, David Feinberg³, and Jin Hyung Lee^1,4,5,6
1Neurology and Neurological Sciences, Stanford University, Stanford, CA, United States, ²Molecular and Cellular Physiology, Stanford University, Stanford, CA, United States, ³Helen Wills Neuroscience Institute, University of California, Berkeley, CA, United States, ⁴Bioengineering, Stanford University, Stanford, CA, United States, ⁵Neurosurgery, Stanford University, Stanford, CA, United States, ⁶Electrical Engineering, Stanford University, Stanford, CA, United States

We attempted to establish the mesoscale layer-specific fMRI representation of neuronal activity using layer-specific Cre-driver mouse lines, optogenetic stimulations, fMRI and electrophysiological recordings. Although laminar fMRI responses were distinct during L2/3, L4, L5 and L6 stimulations, all fMRI responses increased along the cortical depth. This phenomenon was, however, not observed in LFP and spike recordings. This discrepancy between fMRI, LFP and spiking may be due to the draining veins transporting deoxyhemoglobin from the deeper layers to the superficial layers. Future studies may take into account of neurovasculature to elucidate the exact mechanisms of mesoscale layer-specific neurovascular coupling.

Uk-Su Choi^1,2, Seiji Ogawa³, and Ikuhiro Kida^1,2
1Center for Information and Neural Networks, NICT, Suita, Japan, ²Graduate School of Frontier Biosciences, Osaka University, Suita, Japan, ³Kansei Fukushi Research Institute, Tohoku Fukushi University, Sendai, Japan

To examine the layer-dependent fMRI responses of face processing in human visual cortex, we acquired submillimeter functional and anatomical data at 7T. Here, we measured fMRI responses to left single and paired faces with various interstimulus intervals; furthermore, we calculated the repetition suppression (RS) ratio from three cortical layers in the right primary visual cortex (V1) and occipital face area (OFA). The fMRI response and RS ratio of superficial and middle layers of the right V1 were similar to those of all right OFA layers. Hence, the layers in different hierarchical visual areas were modulated in the same manner.

Silke Kreitz^1,2, Angelika Mennecke¹, Laura Cristina Konerth ², Armin Nagel³, Frederic Laun³, Michael Uder³, Arnd Doerfler¹, and Andreas Hess^2
1Department of Neuroradiology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany, ²Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander University Erlangen-Nurnberg, Erlangen, Germany, ³Department of Radiology, University Hospital of the Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany

7T MRI is hoped to improve diagnostics, therapy and research of neurological diseases. Here, we characterize the influence of field strength on fMRI approaches including task based and RS-fMRI. Quality metrics revealed a basic separation of 3T and 7T fMRI data, mainly by tSNR, MDI, CNR and EFC. 7T fMRI showed higher BOLD response amplitudes, more functional connections and higher connectivity strength especially in inferior brain regions. Though higher variability between subjects at 7T likely requires enhanced statistical power in group comparisons, intra individual fMRI measurements might detect subtle connectivity changes at 7T useful for diagnosis and therapy.

Lebo Wang¹, Kaiming Li², and Xiaoping Hu^1,2
1Department of Electrical and Computer Engineering, University of California, Riverside, Riverside, CA, United States, ²Department of Bioengineering, University of California, Riverside, Riverside, CA, United States

Traditional deep learning architectures have met with limited performance improvement on fMRI data analysis. Our connectivity-based graph convolutional network modeled fMRI data as graphs and performed convolutions within connectivity-based neighborhood. We demonstrate that our approach is substantially more robust in classifying Autism Spectrum Disorder (ASD) patients from normal subjects compared with those in published work. Extracting spatial features and averaging across frames are beneficial in reducing variance and improving classification accuracy.