Network to Network Functional Connectivity Modulated by Transcranial Alternating Current Stimulation in Chronic Stroke

Transcranial alternating current stimulation (tACS) is an emerging non-invasive neuro-modulation technique which has been proved to enhance neuro-rehabilitation in stroke. Simultaneous acquisition of neuroimaging data with brain stimulation allow a noninvasive investigation of the brain dynamic changes during the process. In the concurrent tACS-fMRI study, fMRI data were collected in 13 chronic stroke individuals under different tACS protocols (10 Hz, 20 Hz and sham). Resting-state fMRI was acquired before, during and after the stimulation to investigate the dynamic process of neural response. In this preliminary analysis, ICA across conditions and subjects was used to extracted typical brain networks. The extracted networks were used as masks to do network to network functional connectivity analysis. Functional connectivity between networks was found to be significantly modulated for default-mode network, contralesional frontoparietal network and executive control network, and this modulation effect varied for different stimulation frequency. 10 Hz tACS exhibited stronger modulation effects in the brain network interactions.