Does Transcranial Direct Current Stimulation Improve Healthy Working Memory?: A Meta-analytic Review

Area of Science:

• Cognitive Neuroscience
• Neuroscience
• Neuromodulation

Background:

• Transcranial direct current stimulation (tDCS) is explored for cognitive enhancement.
• Recent meta-analyses show limited effects of tDCS on working memory (WM) in healthy individuals.
• This study re-evaluates previous findings and presents a more sensitive meta-analysis.

Purpose of the Study:

• To investigate the potential of tDCS for enhancing working memory (WM) performance.
• To re-examine previous meta-analyses and address potential underestimations of tDCS effects.
• To identify conditions under which tDCS may effectively improve WM.

Main Methods:

• Conducted a comprehensive meta-analysis of 31 studies on anodal tDCS and WM.
• Focused on stimulation over left and right dorsolateral prefrontal cortex (DLPFC) and right parietal lobe.
• Included analyses of left DLPFC stimulation combined with WM training.

Main Results:

• A small but significant enhancement in WM was found for left DLPFC stimulation combined with WM training.
• Left DLPFC stimulation alone showed a trend towards enhancement, but was not significant after publication bias correction.
• No other significant effects were observed for different stimulation sites or conditions.

Conclusions:

• The primary potential for tDCS to enhance working memory (WM) likely lies in its application during cognitive training.
• tDCS may be most effective as an adjunct to WM training rather than a standalone cognitive enhancer.
• Further research is needed to fully elucidate the parameters for optimal tDCS-induced WM enhancement.