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=17

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=<sec id="sec1"><title>Objects</title><p>This study aimed to investigate the immediate effects of fronto-parietal θ HD-tACS on a dual task of working memory-postural control.</p></sec><sec id="sec2"><title>Methods</title><p>In this within-subject cross-over pilot study, we assessed the effects of 20 min of 6 Hz-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.</p></sec><sec id="sec3"><title>Results</title><p>Within the tACS group, we found a 5.3% significant decrease in working memory response time under the dual-task following tACS (<italic>t</italic> = −3.157, <italic>p</italic> = 0.005, Cohen’s <italic>d</italic> = 0.742); phase synchronization analysis revealed a significant increase in the phase locking value (PLV) of θ band between F3 and P3 after tACS (<italic>p</italic> = 0.010, Cohen’s <italic>d</italic> = 0.637). Correlation analyses revealed a significant correlation between increased rs-EEG θ power in the F3 and P3 channels and faster reaction time (<italic>r</italic> = −0.515, <italic>p</italic> = 0.02; <italic>r</italic> = −0.483, <italic>p</italic> = 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 (<italic>p</italic>-values &lt;0.05).</p></sec><sec id="sec4"><title>Conclusion</title><p>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.</p></sec>