Abstract
Recent neurophysiological studies provide inconsistent results of fronto-parietal network stimulation for altering working memory capacity. This study aimed to boost working memory capacity by manipulating the activity of the fronto-parietal network via dual-site High-Definition transcranial direct current stimulation. Forty-eight participants were randomly assigned to three stimulation groups, receiving either simultaneous anodal stimulation of the frontal and parietal areas (double stimulation), or stimulation of the frontal area only (single stimulation), or the placebo stimulation (sham) to frontal and parietal areas. After the stimulation, we used an Operation Span task to test memory accuracy, mathematical accuracy, time of calculation and memorizing and recall response time across the three groups. The results revealed an enhancement of memory accuracy and a reduction of time of calculation in the double stimulation group compared to others. In addition, recall response time was significantly decreased in the double and single stimulation groups compared to sham. No differences in mathematical accuracy were observed. Our results confirm the pivotal role of the fronto-parietal network in working memory and suggest its functional dissociation, with the frontal component more implicated in the retrieval stage, and the parietal component in the processing and retention stages.
Significance statement Simultaneous fronto-parietal dual-site transcranial direct current stimulation significantly enhanced performance and reduced response times in a complex working memory task compared to single-site frontal and sham groups.
Footnotes
The completion of this research project would not have been possible without the contributions and support of Stanislav Otstavnov who helped with recruiting participants.
Authors report no conflict of interest
This work/article is an output of a research project implemented as part of the Basic Research Program at the National Research University Higher School of Economics (HSE University) and was carried out using HSE Automated system of non-invasive brain stimulation with the possibility of synchronous registration of brain activity and registration of eye movements.
This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license, which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properly attributed.
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