Effects of prefrontal tDCS on executive function: Methodological considerations revealed by meta-analysis

Area of Science:

• Neuroscience
• Cognitive Psychology
• Neuromodulation

Background:

• Executive functions (EF) are crucial cognitive processes.
• Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique.
• Previous research on tDCS effects on EF has yielded mixed results.

Purpose of the Study:

• To meta-analyze the effects of single-session tDCS targeting the dorsolateral prefrontal cortex (DLPFC) on executive functions in healthy individuals.
• To investigate potential moderators of tDCS efficacy on different EF domains.

Main Methods:

• A meta-analysis of 27 studies with 71 effect sizes was conducted.
• Studies targeted the DLPFC using single-session tDCS.
• Executive functions were categorized into inhibition, set-shifting, and updating.

Main Results:

• No significant overall effect of tDCS (anodal, cathodal, or bilateral) on EF was found.
• Anodal unilateral tDCS showed a significant effect on updating tasks, but not inhibition or set-shifting.
• Extracranial cathodes and smaller anode sizes significantly moderated positive effects of anodal tDCS.

Conclusions:

• Anodal DLPFC tDCS is more effective for improving updating ability than inhibition or set-shifting.
• Optimal electrode configurations (extracranial cathodes, small anodes) enhance the general executive function benefits of anodal tDCS.
• Future research should explore task-specific effects and methodological moderators in tDCS meta-analyses.