Room 151 AG

16:00 - 18:00

Moderators:

Shella D. Keillholz, Christopher P. Pawela

Xiaoping P. Hu
 

Yang Fan¹, Qihong Zou¹, and Jia-Hong Gao^1,2
1MRI Research Center and Beijing City Key Lab for Medical Physics, Peking University, Beijing, China, ²Brain Research Imaging Center and Department of Radiology, University of Chicago, Chicago, Illinois, United States

The thalamus plays an important role in brain functions. Limitations of the previous studies on parcellation of the thalamus lie in the determination of the number of subdivisions. Here, a novel functional connectivity-based approach was obtained. Various cluster solutions have been proposed and several indices were used to evaluate these solutions. An optimal solution with relative high robustness, symmetry and well hierarchy structure was obtained. Partial correlation was used to detect cortical regions which were specifically functional connected to each subdivision from the optimal solution. Correspondences to the anatomical connectivity were revealed, which proved validity of our approach.

Zhifeng Liang¹ and Nanyin Zhang^1
1Center for Comparative NeuroImaging, Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA, United States

In the present study we have employed an awake animal imaging approach to systematically map thalamocortical connectivity for multiple thalamic nucleus groups in rats. The findings have provided important evidence supporting the validity of rsfMRI measurement in awake animals. More importantly, they have made it possible to non-invasively investigate the function, neuroplasticity and mutual interactions of thalamic nuclei and thalamo-cortical networks in animals.

Chiara Mastropasqua^1,2, Marco Bozzali³, Giacomo Koch^4,5, Carlo Caltagirone^6,7, and Mara Cercignani^1,8
1Neuroimaging Laboratory, IRCCS Santa Lucia, Rome, Italy, ²Dep of Neuroscience, Trieste University, Trieste, Italy, ³Neuroimaging Laboratory, Santa Lucia Foundation, Rome, Italy, ⁴Department of Clinical and Behavioural Neurology, IRCCS Santa Lucia, Rome, Italy, ⁵Stroke Unit, Department of Neuroscience, University of Rome Tor Vergata, Rome, Italy, ⁶Department of Clinical and Behavioural Neurology, IRCCS Santa Lucia Foundation, Rome, Italy, ⁷Department of Neuroscience, University of Rome Tor Vergata, Rome, Italy, ⁸Clinical Imaging Sciences Centre, Brighton & Sussex Medical School, Falmer, United Kingdom

Our aim is to validate precedent approach for thalamic parcellation based on probabilistic tractography and to compare structural and functional connectivity between the thalamus and the cerebral cortex. We used DTI tractography to define distinct thalamic nuclei connected to different cortical areas. Seed-based RS-fMRI was then performed to identify the cortical areas more strongly connected with thalamic nuclei previously obtained. The results were visually compared to cross-validate these 2 commonly used approaches to assess anatomical and functional connectivity. Our results confirm the reproducibility of thalamic parcellation based on probabilistic tractography and show that these two methods yield partially consistent results.

Joseph H. Rosenberg¹, Chandler R. Sours¹, Jiachen Zhuo¹, Elijah O. George^1,2, and Rao P. Gullapalli^1
1Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, United States, ²Department of Bioengineering, University of Maryland, College Park, MD, United States

Mild traumatic brain injury (mTBI) patients received a resting state fMRI scan and completed the Automated Neuropsychological Assessment Metrics (ANAM) at the acute (10days) and sub-acute (1 month) stages of injury. During the sub-acute stage, mTBI patients demonstrated reduced interhemispheric functional connectivity (IH-FC) in both the thalamus and the dorsolateral prefrontal cortex, as well as deficits on the ANAM, compared to matched controls. Patients reporting Post-Concussive Syndrome (PCS) demonstrated a significant reduction in thalamic IH-FC from the acute stage to the sub-acute stage. PCS patients also performed significantly worse on the ANAM than those without.

Adam Bauer¹, Andrew Kraft², Patrick Wright¹, Jin-Moo Lee², and Joseph Culver^1
1Radiology, Washington University in Saint Louis, Saint Louis, MO, United States, ²Neurology, Washington University in Saint Louis, Saint Louis, MO, United States

Stroke is a major health concern in the US. It is becoming increasingly apparent that a brain-wide assessment of functional connections may provide better insight into recovery potential than assessment of anatomic infarction. While recent findings suggest that bilateral connectivity is associated with recovery, signal regression can influence interpretation of functional connectivity patterns. Neglecting to distinguish unique signals within and across hemispheres may confound potentially recovery-relevant information. We applied a novel functional connectivity optical intrinsic signal imaging technique to a mouse model of ischemic stroke to evaluate altered regional hemodynamics and how they can affect measurements of connectivity after stroke.

Dany D'Souza¹, Andreas Bruns², Basil Kuennecke¹, Daniela Alberati¹, Edilio Borroni¹, Markus von Kienlin¹, Annemie Van der Linden³, and Thomas Mueggler^1
1pRED, Pharma Research & Early Development, DTA Neuroscience, F. Hoffmann-La Roche AG, Basel, Switzerland, ²pRED, Pharma Research & Early Development, DTA Neuroscience, F. Hoffmann-La Roche Ltd, Basel, Switzerland, ³Bio-Imaging Lab, University of Antwerp, Antwerp, Belgium

Using resting-state fMRI, we characterized 1) complexity of spontaneously fluctuating BOLD signals, 2) alteration of functional connectivity between brain regions in rats after a sub-anaesthetic dose of ketamine, an NMDAR antagonist known to induce positive and negative symptoms, and cognitive deficits in healthy subjects as well as psychotic-like behaviour in rodents. However, the neural circuitry underlying the psychotic symptoms produced by ketamine is poorly understood. Our findings of functional activity and connectivity alterations specifically in prefrontal, auditory and visual cortex may be linked to the disturbed neural oscillation and synchrony putatively underlying the psychotic-like behavior observed in this model.

Fatima Ali Nasrallah¹, Xuan Vinh To¹, Tovia Yun Jie Ng¹, and Kai-Hsiang Chuang^1
1Magnetic Resonance Imaging Group, A*Star Biomedical Research Institutes, Singapore, Singapore, Singapore

Functional connectivity MRI has emerged as a means to map intrinsic brain networks without the need of explicit tasks. We investigated the effects of Donepezil on brain function using Atlantis Watermaze and functional connectivity MRI. Donepezil is a popular treatment for improving cognitive function in Alzheimer’s disease patients. We show that the alteration of the functional connectivity pattern after donepezil treatment is closely associated with cognitive improvement.

Joanes Grandjean¹, Pan He², Aileen Schröter¹, and Markus Rudin^1,3
1Inst. f. Biomedizinische Technik, ETH and University Zürich, Zürich, Switzerland, ²ETH Zürich, Zürich, Switzerland, ³Institute of Pharmacology and Toxicology, University of Zürich, 8057, Switzerland

Functional connectivity (FC) and fractional anisotropy (FA) was measured in ArcAbeta mouse model of Alzheimer's disease at 5, 8, 11, 19 and 21 months of age. Decrease in FC and FA was detectable in 5 months old mice compared to wild-type, in the sensory-motor networks for FC and in the corpus callosum for FA. Changes in FC and FA remained constant over the progression of the disease until the last measurements at 21 months. ArcAbeta develop amyloid plaques starting at 7 months. Our results suggest that changes in FC and FA precede amyloid plaque deposition in the ArcAbeta mouse model.

Russell W. Chan^1,2, Leon C. Ho^1,2, Iris Y. Zhou^1,2, and Ed X. Wu^1,2
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong SAR, China, ²Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China

Previously, it was reported that hippocampal dendritic spine density increased during pregnancy. It suggested that this additional neural plasticity facilitated learning and memory. Moreover, it was confirmed that pregnancy improved spatial learning and memory and, reduced anxiety and stress responsiveness. It was documented that these changes are related to hippocampus. Hence, this study investigated the feasibility of utilizing diffusion tensor imaging and resting-state functional connectivity MRI to detect tissue microstructural changes and functional connectivity changes in the hippocampus respectively. The results indicated that pregnancy induced tissue microstructural and functional connectivity changes in the hippocampus. Furthermore, the results suggested that fractional anisotropy changes and functional connectivity changes were correlated and coupled during pregnancy.