Transcranial Random Noise Stimulation Boosts Early Motion Perception Learning Rather than the Later Performance Plateau

摘要

The effect of transcranial random noise stimulation (tRNS) onvisual perceptual learning has only been investigated during earlytraining sessions, and the influence of tRNS on later performanceis unclear. We engaged participants first in 8 days of training toreach a plateau (Stage 1) and then in continued training for 3 days(Stage 2). In the first group, tRNS was applied to visual areas ofthe brain while participants were trained on a coherent motiondirection identification task over a period of 11 days (Stage 1 +Stage 2). In the second group, participants completed an 8-daytraining period without any stimulation to reach a plateau (Stage1); after that, they continued training for 3 days, during whichtRNS was administered (Stage 2). In the third group, participantscompleted the same training as the second group, but duringStage 2, tRNS was replaced by sham stimulation. Coherencethresholds were measured three times: before training, afterStage 1, and after Stage 2. Compared with sham simulation, tRNSdid not improve coherence thresholds during the plateau period.The comparison of learning curves between the first and thirdgroups showed that tRNS decreased thresholds in the early trainingstage, but it failed to improve plateau thresholds. For the secondand third groups, tRNS did not further enhance plateauthresholds after the continued 3-day training period. In conclusion,tRNS facilitated visual perceptual learning in the early stage,but its effect disappeared as the training continued.