Frequency-specific after-effects of transcranial alternating current stimulation (tACS) on motor learning: Preliminary data of a simultaneous tACS-EEG-NIRS study

Introduction: Motor learning is associated with changes in synchronized oscillatory activity at alpha (8-12 Hz) and beta (12-30 Hz) frequencies. Numerous studies demonstrated the frequency-specific modulation of tACS on ongoing oscillatory activity, cortical excitability and motor behavior. However, the underlying mechanisms by which tACS is induced and persist as well as the modulation of motor learning in complex tasks remain ambiguous. Thus, we combined electroencephalography (EEG) and near-infrared spectroscopy (NIRS) during a bimanual visuomotor coordination task (2HAND, Schuhfried) to investigate electrophysiological and hemodynamic effects of tACS on motor learning.