Abstract
Repetitive transcranial magnetic stimulation when paired with skilled motor practice shows promise for motor recovery after stroke via modulation of cortical excitability. Specifically, continuous theta burst stimulation (cTBS) can be used to inhibit overactivity in the contralesional cortex observed during skilled motor practice with the affected limb, facilitating neuroplastic change in the ipsilesional cortex necessary for recovery. However, response to cTBS is varied; how cTBS influences brain activity after stroke is not well known. Here, 29 participants with middle cerebral artery stroke (> 6 months post-stroke; 7 females; 66.9 ± 13.3 years old; 10 left hemisphere stroke) underwent both active and sham cTBS, counterbalanced across individuals. Before and after cTBS, participants completed a functional magnetic resonance imaging experiment where they engaged in a motor imagery (the mental rehearsal of a movement) task involving opening a door with their affected arm/hand. Preliminary results (N = 23) suggest cTBS leads to increased activity in the posterior parietal cortex (post > pre) during motor imagery, but only for individuals with right hemisphere lesions. No changes in brain activity were observed following cTBS or sham in the left hemisphere lesioned individuals. Preliminary findings suggest that while cTBS effectively increases activity in the lesioned hemisphere, specifically in regions involved in sensory integration and visuospatial attention, lesion location may contribute to the variable response to cTBS after stroke. Additional planned analyses will test associations between change in corticospinal excitability, I-wave latency, and change in brain activity to further inform on response to cTBS after stroke.
