Sex Mediates the Effects of High-Definition Transcranial Direct Current Stimulation on "Mind-Reading"

Area of Science:

• Neuroscience
• Cognitive Psychology
• Social Neuroscience

Background:

• Sex differences in social cognitive abilities, including Theory of Mind (ToM), are well-documented.
• The dorsomedial prefrontal cortex (dmPFC) is a critical hub for social cognition.
• Understanding how neuromodulation affects social cognition differently across sexes is crucial.

Purpose of the Study:

• To investigate if sex mediates the effects of high-definition transcranial direct current stimulation (HD-tDCS) on the dmPFC on social cognitive performance.
• To examine the impact of anodal vs. cathodal HD-tDCS on the Reading the Mind in the Eyes Test (RMET).
• To assess the specificity of dmPFC stimulation effects on ToM.

Main Methods:

• A double-blind, sham-controlled study involving 40 healthy young adults (18-35 years).
• Participants received either anodal or cathodal HD-tDCS over the dmPFC in two separate sessions.
• Performance on the RMET, a measure of ToM, was assessed after each stimulation condition.

Main Results:

• Anodal HD-tDCS to the dmPFC significantly increased RMET accuracy exclusively in females.
• Cathodal stimulation and sham stimulation did not yield significant effects on RMET performance in either sex.
• A follow-up study stimulating the right temporoparietal junction showed no sex-specific effects, supporting the regional specificity of the dmPFC findings.

Conclusions:

• This study provides the first evidence that HD-tDCS of the dmPFC can enhance ToM performance, specifically in females.
• The findings highlight sex-dependent differences in the functional impact of dmPFC stimulation on social cognition.
• Future research on neuromodulation of ToM must account for sex as a significant moderating factor.