Michel R.T. Sinke¹, Willem M. Otte^1,2, Alberto Caimo³, Cornelis J. Stam⁴, and Rick M. Dijkhuizen^1
1Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht, Utrecht, Netherlands, ²Department of Pediatric Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, Netherlands, ³Social Network Analysis Research Centre, Interdisciplinary Institute of Data Science, University of Lugano, Lugano, Switzerland, ⁴Department of Clinical Neurophysiology, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, Netherlands

Comparison of brain networks that differ in size or edge density may be inadequate with frequently applied descriptive graph analysis methods. To resolve this, we propose an alternative framework based on Bayesian generative modeling, allowing unbiased assessment of local substructures that shape the global network topology. Structural networks were derived from DTI-based whole-brain tractography of 382 healthy subjects (age: 20-86 years), and successfully simulated. Despite clear effects of age and hub damage on network topologies, relative contributions of local substructures did not change significantly. The use of generative models may shed new light on the complex (re)organization of the brain.

Jinsong Zhang¹, Lingzhi Wang², and Jun Li^2
1Radiology department,Xijing Hospital, MRI room, Xi'an, China, People's Republic of, ²School of Life Science and Technology, Xidian University, Xi'an, China, People's Republic of

The spinal cord and brain form central nervous system and sensory and motor signals are relayed by spinal cord and processed by brain. Studies have suggested that resting state functional connectivity (rsFC) are fundamental, common feature of the entire nervous system. However, it still remain unknown the correlation between rsFCs within spinal cord and brain. The present study discovered dorsal and ventral resting state networks (RSNs) within spinal cord and sensory-motor RSN within brain. Further, correlation analysis suggest that dorsal and ventral RSNs connected to sensory and motor RSNs respectively. 

Patricia Andrea Vargas^1,2, Ranganatha Sitaram^1,3,4,5, Pradyumna Sepúlveda^2,6, Cristian Montalba², Mohit Rana¹, Cristián Tejos^2,6, and Sergio Ruiz^1,3
1Department of Psychiatry, Faculty of Medicine, Interdisciplinary Center for Neuroscience, Pontificia Universidad Católica de Chile, Santiago, Chile, ²Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile, ³Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany, ⁴Sree Chitra Tirunal Institute of Medical Sciences and Technology, Trivandrum, India, ⁵Institute for Biological and Medical Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile, ⁶Department of Electrical Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile

In recent years there is a growing interest in the potential application of Brain-Computer interfaces (BCI) for psychiatric and neurological disorders. After stroke, if the primary motor cortex (M1) is affected, it is common to find a “deactivation” of the contralateral cerebellum.

The aim of this study was to evaluate  the feasibility of achieving volitional control of M1-cerebellum functional connectivity, in healthy subjects with an fMRI-BCI system.

The results indicate that volitional self-regulation of cerebellum-M1 connectivity is feasible with fMRI-BCI. The data also suggests that cerebellum is more easily recruited than M1.

Xixi Zhao¹, Junling Wang¹, Xiangliang Tan¹, Xiang Xiao¹, Zeyu Zheng¹, Yingjie Mei², Queenie Chan³, Yikai Xu¹, Ru Yang⁴, and Qianjin Feng^4
1Department of Medical Imaging Center, Nanfang Hospital, Southern Medical University, Guangzhou, China, People's Republic of, ²Philips Healthcare, Guangzhou, China, People's Republic of, ³Philips Healthcare, HongKong, China, People's Republic of, ⁴2School of Biomedical Engineering and Guangdong Provincial Key Laboratory of Medical Image Processing, Southern Medical University, Guangzhou, China, People's Republic of

NAc was supposed be involved in epileptogenesis, especially shell portion. The exact parcellation within the NAc and structural alterations in vivo of NAc subdivisions in EP patients remains unclear. We used diffusion probabilistic tractography to subdivide NAc into putative core shell subdivisions in individual mTLE patients for guiding NAc shell stereotactic target localization. Our results revealed that both left and right mTLE patients exhibited decreased FA and increased MD in shell portion of bilateral NAc, which may reflect neuronal degeneration and damage caused by seizure mainly in shell portions, and suggest a possible role of the NAc shell in epileptogenesis

Linying Guo¹, Tian Tian¹, and Wenzhen Zhu^1
1Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Hubei, China, People's Republic of

Previous studies on trigeminal neuralgia (TN) have mainly focused on peripheral nerve damage, but little is known about the structural and functional changes in central nervous system (CNS) that can occur following trigeminal nerve dysfunction. In this study, we used diffusion kurtosis imaging (DKI) and functional connectivity density (FCD) mapping in TN patients to investigate both structural and functional changes in CNS. We found TN patients have correlated white matter and FCD reorganization that may contribute to pathologic algogenic system. Our findings may be helpful guidance for systematic therapeutics in both peripheral and central nerves.

Armin Iraji¹, Natalie Wiseman², Robert Welch³, Brian O'Neil³, E. Mark Haacke^1,4, and Zhifeng Kou^1,4
1Department of Biomedical Engineering, Wayne State University, Detroit, MI, United States, ²Department of Psychiatry and Behavioral Neurosciences, Wayne State University, Detroit, MI, United States,³Department of Emergency Medicine, Wayne State University, Detroit, MI, United States, ⁴Department of Radiology, Wayne State University, Detroit, MI, United States

Most functional and structural MRI studies in mild traumatic brain injury (mTBI) are performed at the group level. Recently, there is concern regarding the validity of group-level analyses findings in mTBI due to the heterogeneity of TBI. However, while group-level analysis cannot demonstrate a complete view of impairments, we hypothesize that there are similar patterns in group-level and subject-level findings, especially in higher order brain activities and networks. We evaluated this in the DMN using a new framework known as the connectivity domain. This is the first study of utilizing the connectivity domain to investigate changes after a brain disorder.

Ana Carina Mendes¹, Ana-Maria Oros-Peusquens², André Santos Ribeiro^1,3, Karl-Josef Langen², Carolin Weiß Lucas⁴, Nadim Jon Shah², and Hugo Alexandre Ferreira^1
1Institute of Biophysics and Biomedical Engineering, Faculty of Sciences of the University of Lisbon, Lisbon, Portugal, ²Forschungszentrum Juelich GmbH, Institute of Neurosciences and Medicine-INM4, Juelich, Germany, ³Centre for Neuropsychopharmacology, Division of Brain Sciences, Department of Medicine, Imperial College London, London, United Kingdom, ⁴Center of Neurosurgery, University of Cologne, Cologne, Germany

Methods capable of mapping brain connectivity pathways may prove useful by providing valuable information in order to prevent sequelae following a surgical intervention. This study presents an approach for the whole-brain connectivity evaluation of nine patients with lateralized gliobastoma, using the Multimodal Imaging Brain Connectivity Analysis (MIBCA) toolbox to process MR and PET data. Results show changes in connectivity metrics across both hemispheres for all patients accompanied by an increased number of fibres which may result from reorganization of connectivity pathways caused by the disruption of the original ones by the tumour.

Matthew Hey¹, Luis Colon-Perez², William Triplett³, David Fitzgerald⁴, and Thomas Mareci^5
1University of Florida, Gainesville, FL, United States, ²Department of Psychiatry, University of Florida, Gainesville, FL, United States, ³Department of Physical Therapy, University of Florida, Gainesville, FL, United States, ⁴Department of Neurology, University of Florida College of Medicine, Gainesville, FL, United States, ⁵Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, FL, United States

The spatial resolution of diffusion-weighted (DWI) images limits the white matter streamline fiber tracks, which can be followed in the brain stem. To address this issue, we introduce a high spatial resolution protocol and the use of a threshold to limit the false positive in streamline track density maps by requiring that a minimum amount of fibers pass through a voxel. This provides increased accuracy in the visualization of streamlines connecting specific regions of the brain stem and may allow the recognition of structural abnormalities due to neurological diseases.  

Julia Boonzaier¹, Geralda A. F. van Tilborg¹, Mark J.R.J. Bouts^2,3,4, Petar P.I. Petrov⁵, Caroline L. van Heijningen¹, Gerard van Vliet¹, Annette van der Toorn¹, Sebastiaan F.W. Neggers⁵, and Rick M. Dijkhuizen^1
1Center for Image Sciences, University Medical Center Utrecht, Utrecht, Netherlands, ²Institute of Psychology, Leiden University, Leiden, Netherlands, ³Department of Radiology, Leiden University Medical Center, Leiden, Netherlands, ⁴Leiden Institute for Brain and Cognition (LIBC), Leiden University, Leiden, Netherlands, ⁵Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, Netherlands

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive neuromodulation technique with the ability to change cortical excitability, however its precise mechanism of action is not completely understood. Therefore, by acquiring resting-state fMRI and perfusion MRI data we assessed the influence of unilateral low-frequency (inhibitory) rTMS on functional connectivity and hemodynamics instimulated cortical tissue in rats. After four consecutive days of rTMS we measured reduced interhemispheric functional connectivity between homotopic sensorimotor regions, while cerebral blood flow remained largely unaffected. This reduction in interhemispheric functional connectivity may be due to the inhibitory effect of low-frequency rTMS on cortical excitability.