Date of Award

Spring 5-2016

Author's Department

Biomedical Engineering

Degree Name

Master of Science (MS)

Degree Type



Stroke is the most common cause of long-term severe disability and the motor system that is most commonly affected in stroke. One of the mechanisms that underlies recovery of motor deficits is reorganization or remapping of functional representations around the motor cortex. This mechanism has been shown in monkeys, but results in human subjects have been variable. In this thesis, I used a database that includes longitudinal behavioral and multimodal imaging data in both stroke patients and healthy controls for two research projects. Firstly, I improved an automatic lesion segmentation method to aid in the identification of the location and extent of the stroke in structural magnetic resonance imaging (MRI) images. I developed a point and click interface that allows for the automatic segmentation as well as selecting lesions generated at different thresholds based on the contrast of the T1 images. Second, I investigated the effect of subcortical strokes on motor representations by measuring changes in the topography of inter-hemispheric resting state functional connectivity (FC) MRI to track changes of the hand representation in the damaged hemisphere shows a higher variation across the medial-lateral axis, suggesting a shift in neighboring body representations along the motor strip. During recovery, however, there is a shift in an anterior-posterior direction suggesting a shift into sensory and premotor regions. Obtaining lesion profile and understanding its effect on the functional connectivity can provide us with useful information on the effects of stroke on brain structure and function, which in turn will help in the prognosis and rehabilitation of stroke patients.


English (en)


Maurizio Corbetta

Committee Members

Dennis Barbour, Dan Moran


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