Effects of tDCS on tactile perception in musicians and non-musicians

Brain plasticity in somatosensory cortex can be facilitated by brain stimulation. To elucidate the relationship between the magnitude of plasticity and tactile performance with tactile expertise, we investigated the effects of transcranial direct current stimulation (tDCS) on tactile perception in musicians and non-musicians. At three separate days, 17 semi-professional musicians (e.g., piano or violin players) and 16 musical novices aged 18-27 years received 15 minutes of 1mA anodal (a-tDCS), cathodal (c-tDCS) or sham tDCS in a pseudorandomized design. Pre and post tDCS, tactile sensitivity (Touch Detection Task; TDT) and discrimination performance (Grating Orientation Task; GOT) were assessed. For further analysis, the weekly hours of instrument-playing and computer-typing were combined into a ‘tactile experience’ variable. For GOT, but not TDT, a significant group effect at baseline was revealed with musicians performing better than non-musicians. TDT thresholds, were significantly reduced after a-tDCS but not c-tDCS or sham stimulation. While both experts’ and novices’ performance improved after anodal stimulation, neither musical nor tactile expertise were directly associated with the magnitude of this improvement. Low performers in TDT with high tactile experience profited most from a-tDCS. We conclude that tactile expertise may facilitate somatosensory cortical plasticity and tactile learning in low performers.