# The use of transcranial direct current stimulation to facilitate motor skill reactivations of a choice reaction time task in adults

## TL;DR

This study shows that short practice sessions with brain stimulation can improve motor skills as much as longer sessions.

## Contribution

It demonstrates that brief tDCS-enhanced reactivations can match full-length practice in motor learning.

## Key findings

- RT improved significantly from pre-test to post-test across all groups.
- Brief reactivation + tDCS achieved similar RTs to full-practice groups.
- Women showed slower initial RTs and less improvement with practice.

## Abstract

Motor skill acquisition involves fast and slow learning phases, typically requiring extended practice. This study explored whether brief reactivations of a choice reaction time (CRT) task, combined with anodal transcranial direct current stimulation (tDCS) over the primary motor cortex (M1), could yield performance improvements comparable to full‐length practice. A total of 120 healthy adults were randomized into six groups varying in tDCS use (2 mA for 5 or 20 min) and practice duration (5 or 20 min). Reaction time (RT) and error rate were assessed across sessions. Across all groups, RT significantly improved from 423.5 ± 116.8 ms at pre‐test to 357.9 ± 63.4 ms post‐test (p < 0.001), of the first session. RTs at session 4 (377.8 ± 66.2 ms) remained significantly faster than baseline (p < 0.001), though slightly slower than immediate post‐test in session 1 (p = 0.172). No significant between‐group differences emerged in RT or error rate, though the brief reactivation + tDCS group achieved RTs similar to the full‐practice group. When separated by sex, women showed slower reaction times initially and less improvement in reaction times with practice. These results suggest that brief, tDCS‐enhanced reactivations can preserve behavioral improvements in learning, though their neurophysiological effects remain inconclusive.