Current surgical treatments for Parkinson's disease have associated risks that may prevent patients from being offered surgery called "deep brain stimulation" or DBS. This is mainly because electrodes have to be placed through brain tissue to reach the target. Stimulation at the surface of the brain might be a potential alternative, but current research has not shown consistent results, and this may be because the mechanism of action is not clear. In this study, we aim to stimulate and record the brain at the surface to help answer this question and potentially improve the consistency and effectiveness of this treatment.

Transcranial direct current stimulation (tDCS) can be an effective therapy for stroke recovery patients. However, the extent to which patients show improvements with tDCS is highly variable. This variability may arise due to the differences of stroke location in the brain and because of differences in brain damage, all of which may differ between patients. If the relationship between these factors and tDCS efficacy were known, recovery from stroke using tDCS might become more predictable. Our overall objective is to understand potential measures of tDCS efficacy that may someday allow for optimization of clinical outcomes and patient care.