Short-term sensorimotor practice reduces somatosensory temporal discrimination threshold and enhances somatosensory...

To investigate whether short-term sensorimotor practice alters the somatosensory temporal discrimination threshold (STDT), primary somatosensory cortex (S1) responses, and intracortical inhibition.

Thirty-eight healthy adults were randomly assigned to either a coin rotation (CR, n = 19) or a finger tapping (FT, n = 19) group and completed 10 training sessions. CR performance, STDT, somatosensory evoked potentials (SEPs), high-frequency oscillations (HFOs), and paired-pulse depression (PPD) at interstimulus intervals (ISI) of 5 ms and 30 ms were assessed before and after training.

CR performance improved by 33% (p < 0.001). STDT decreased on the trained side (main effect of test: p = 0.017), with no between-group difference or interaction. N20/P25 amplitude and HFOs (single-stimulus and ISI 5 ms conditions) increased after training. PPD at both ISIs showed no significant effects.

Short-term sensorimotor practice reduced STDT and enhanced S1 responses without detectable changes in PPD-indexed inhibition. The lack of between-group differences suggests these effects may reflect a common effect of repetitive sensorimotor practice across the two active tasks tested, rather than task-specific learning.

In this paradigm, STDT improved without detectable changes in PPD-indexed inhibition, suggesting that alternative mechanisms of sensory temporal processing warrant consideration.