Touch-Related Electrophysiology Activity Promotes Human Movements Initiation

Although touch has been shown to improve motor performance, its specific influence on movement initiation and the underlying neurophysiological mechanisms remain unclear. Here, we demonstrate that tactile input robustly enhances movement initiation, although the strength of this facilitation varies across touch types. Using a tactile Go/No-Go Task during different types of touch (i.e., self-touch, object-touch and other-touch), we found that all these types of touch reduced reaction time (RT). To elucidate the neural substrates of this behavior, we employed multimodal neurophysiological assessments. The results of Transcranial magnetic stimulation (TMS) revealed that touch increased short-interval intracortical inhibition (SICI) ratios, indicating reduced intracortical inhibition and enhanced corticospinal excitability (CSE). Enhanced CSE was associated with faster motor initiation, which was most pronounced under self-touch conditions. Electroencephalography (EEG)-based analyses and behavioral somatosensory measures revealed touch-related changes in somatosensory processing. Specifically, touch, especially self-touch, was associated with increased cortical somatosensory evoked potential (SEP) amplitudes, reduced somatosensory temporal discrimination thresholds (STDTs), and enhanced network-level functional connectivity. Together, these findings suggest that touch may shorten movement initiation time, possibly by modulating somatosensory processing within central somatosensory networks and promoting corticospinal readiness, thereby facilitating sensorimotor transformation. Our results can inform future motor rehabilitation using touch-based interventions.