Cortical Resting-State Activities May Predict Anodal tDCS-Induced Facilitation of Dynamic Balance Training

Abstract: In this study, by combining a-tDCS with dynamic balance training and targeting two different brain regions, we aimed to find out the effective target for tDCS to facilitate learning performance and enhance balance in younger adults. Besides targeting the sensorimotor cortex (M1), we alternatively applied a-tDCS to the prefrontal cortex (left DLPFC). We further explored changes in resting-state oscillations induced by a-tDCS combined with balance training. Additionally, in this study, we investigated whether rs-EEG can predict practice effects in the balance task. Forty-three healthy young adults were recruited for this study. Results revealed that a-tDCS was effective in facilitating balance performance for both experimental groups compared to sham. Further, our data confirmed retention effects for the Cz and sham group on the second day of training, while this retention was not confirmed for the F3 group. Our data did not confirm any transfer effects of dynamic balance training to untrained static balance tasks. With respect to the EEG analysis, our data revealed an increase in relative Alpha power in the post relative to the pre-test, independent of Stimulation Group. Results further revealed an association between theta and beta power at the pre-test and a practice effect. We conclude that our findings thus substantially extend previous studies by demonstrating the application of a-tDCS to facilitate changes in brain networks in targeted brain areas, which are not only improving motor execution but also top–down executive control.