Project 467156

Brain waves are known for their importance in the transmission of information in brain circuits and in the integration of cognitive neural processes. Electroencephalography (EEG) is a technique that can capture these brain waves with high temporal resolution. A particular pattern observed during movement execution is the movement-related beta desynchronization (MRBD), a decrease in beta power thought to reflect increased excitability of neurons in motor areas. Abnormal patterns are present post-stroke whereas lower MRBD and higher resting beta power correlate with movement deficits in stroke patients. This project proposes to use EEG and cutting-edge high-definition non-invasive brain stimulation (HD-NIBS) ; HD transcranial direct current stimulation (HD-tDCS) and HD transcranial alternating current stimulation (HD-tACS) ; simultaneously to modulate motor cortex activity in stroke individuals. We will quantify the effect of NIBS protocols on resting beta band power and on MRBD. We will also describe the ongoing effects of NIBS on brain waves in real-time. The experimental protocol involves 20 stroke participants performing a motor handgrip task while EEG is being recorded. Participants will receive either HD-tACS, HD-tDCS or sham stimulation randomized across 3 visits. We hypothesize that HD-tDCS and HD-tACS on the motor cortices will induce a reduction in resting beta band power by increasing the excitability of the neurons in the targeted location and help normalize the MRBD size. This study will contribute to a better knowledge of how NIBS affects brain activity in stroke patients. The results will be ultimately used to design optimal NIBS protocols as part of a closed-loop neurofeedback approach to improve patients recovery of their motor functions.