Transcranial direct current stimulation on prefrontal and parietal areas enhances motor imagery.

Considering the potential effect of transcranial direct current stimulation (tDCS) to improve motor imagery the purpose of this study was to investigate the effects of tDCS on prefrontal and postparietal cortex in hand mental rotation (HMR). This investigation was a single-blind, randomized study which 60 healthy right-hand college students (30 males and 30 females, age 24.27±0.19 years) volunteered to attend. Using a simple random method, participants were divided into four groups: anodal: F4 (n=15) and P4 (n=15), sham: F4 (n=15) and P4 (n=15). Participants were asked to perform HMR task before and after five sessions of tDCS. Results showed that there is a significant difference between the pretest and post-test of reaction time (t=10.09, d.f.=29, P=0.005) and accuracy (t=-5.04, d.f.=29, P=0.005) in two sites (F4, P4) in anodal group, also two-way analysis of variance of HMR reaction time showed significant main effect of Group (F=52.458, P=0.000, ηP=0.488) indicating faster response in postanodal Group and Site (F=6.561, P=0.013, ηP=0.107) indicating better response in F4, and in HMR accuracy a significant main effect of Group (F=13.659, P=0.001, ηP=0.199) but not for the main effect of Site (F=0.499, P=0.483, ηP=0.009). According to the findings of the study, it is suggested that tDCS on both prefrontal and postparietal cortex could improve HMR with more effect on prefrontal area.