AUTHOR=Xiao Yanwen , Zhou Junhong , Zhou Rong , Liu Yu , Lü Jiaojiao , Huang Lingyan 

TITLE=Fronto-parietal theta high-definition transcranial alternating current stimulation may modulate working memory under postural control conditions in young healthy adults

JOURNAL=Frontiers in Human Neuroscience

VOLUME=Volume 17 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/human-neuroscience/articles/10.3389/fnhum.2023.1265600

DOI=10.3389/fnhum.2023.1265600

ISSN=1662-5161

ABSTRACT=Objects: This study aimed to investigate the immediate effects of fronto-parietal θ HD-tACS on a dual task of working memory-postural control.
Methods: In this within-subject cross-over pilot study, we assessed the effects of 20 min of 6hz-tACS targeting both the left dorsolateral prefrontal cortex (lDLPFC) and posterior parietal cortex (PPC) in 20 healthy adults (age: 21.6 ± 1.3 years). During each session, single- and dual-task behavioral tests (working memory single-task, static tandem standing, and a dual-task of working memory-postural control) and closed-eye resting-state EEG were assessed before and immediately after stimulation. 
Results: Within the tACS group, we found a 5.3% significant decrease in working memory response time under the dual-task following tACS (t=-3.157, p=0.005, Cohen's d=0.742); Phase synchronization analysis revealed a significant increase in the phase locking value(PLV) of θ band between F3 and P3 after tACS (p =0.010, Cohen's d = 0.637). Correlation analyses revealed a significant correlation between increased rs-EEG θ power in the F3 and P3 channels and faster reaction time (r = -0.515, p = 0.02; r = -0.483, p =0.031, respectively) in the dual-task working memory task after tACS. However, no differences were observed on either upright postural control performance or rs-EEG results (ps < 0.05).
Conclusion: Fronto-parietal θ HD-tACS has the potential of being a neuromodulatory tool for improving working memory performance in dual-task situations, but its effect on the modulation of concurrently performed postural control tasks requires further investigation.