M1 a-tDCS does not acutely enhance motor skill acquisition of a dexterous, timing-based videogame task in adults

Motor skill acquisition involves plastic changes across distributed neural networks, and anodal transcranial direct current stimulation (a-tDCS) applied over primary motor cortex (M1) is often used to modulate excitability and potentially enhance learning. This study examined whether pairing a-tDCS with practice of a dexterous, timing-based videogame task would improve performance and retention relative to SHAM stimulation. Forty healthy adults practiced a Guitar Hero-style rhythm game requiring rapid finger sequencing, fine motor control, and temporal precision while receiving either 1 mA a-tDCS or SHAM stimulation for 20 min. Performance was assessed through accuracy, best continuous note streak, and overstrums across pre-test, practice, post-test, and 24-h retention sessions. Both groups demonstrated significant improvements across all performance measures with practice, and gains were maintained or further enhanced after 24 h. However, no differences were found between the a-tDCS and SHAM groups at any time point, and no time × group interactions emerged. Overall, a-tDCS did not enhance skill acquisition or retention, highlighting task specificity as a key factor in neuromodulation efficacy.