My work in Kesar lab at Emory School of Medicine is focused on the neural mechanism of prism adaptation and augmenting its use in the treatment of post-stroke spatial neglect.
Prism adaptation (PA) is a sensorimotor behavioral phenomenon, which is the mainstream treatment for spatial neglect post-stroke. Right shifting PA induces a shift in global visuospatial motor behavior toward the left hemi-space (aftereffect) leading to immediate and transient changes in visuomotor behavior. Non-invasive sensorimotor electrical stimulation (Stim) may upregulate corticomotor excitability, is commonly used as a therapeutic adjunct during motor training, and may accentuate the effects of PA. However, the cortical plasticity mechanisms related to the behavioral effects of PA, its generalization to the lower limb, and the combinatorial effects of PA and Stim are poorly understood. I use transcranial magnetic stimulation (TMS-motor evoked potentials) as a mechanistic outcome measures to parse out the neural mechanisms of prism adaptation therapy on corticospinal and intracortical excitability. So far, my findings suggest that although both PA+Stim and PA+Sham had similar behavioral aftereffects, only PA+Stim increased cortical excitability in M1 representations of the left upper and lower limb (toward the direction of the PA aftereffect), suggesting that PA+Stim may elicit greater neurophysiological changes and generalization to lower limb than PA alone.
I also map stoke lesions on MRI using imaging software and use multilinear regression analysis to identify responders groups to provide biomarkers for this treatment. A preprint of my study, Prism Adaptation-Induced Modulation of Cortical Excitability of Upper and Lower Limb Muscles is Enhanced with Electrical Stimulation, is available here. This work generates novel information that will inform future design of new and targeted treatment protocols for evidence-based rehabilitation of spatial neglect and gait dysfunctions post-stroke, to improve gait function and quality of life in stroke survivors.
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