Effects of tDCS on Cortical Motor Facilitation in Performing Motor Execution

Abstract

This study aims to reveal how motor execution contributes to cortical motor facilitation during tDCS. Four healthy subjects were participated in two experimental protocols: (1) tDCS with task (i.e., right hand clenching) and (2) tDCS without task. Each subject underwent 3 sessions (before tDCS, tDCS, after tDCS) for each protocol. Oxygenated hemoglobin concentration changes as an outcome measure were collected for all sessions by the multichannel concurrent tDCS-fNIRS cap which was newly developed for the experiment. The anodal tDCS in left motor cortex was targeted. Both protocols reported a significant cortical activation in left motor-relevant cortices after tDCS sessions. Significant cortical activation differences between two protocols were found in targeted motor cortex. Results showed that 'protocol (1) tDCS with task' had higher activation in motor cortex than 'protocol (2) tDCS without task.' We suggest the cortical motor facilitation is enhanced, when the tDCS is performed simultaneously with the motor execution. © 2021 IEEE.