Cortical thickness is related to working memory performance after non-invasive brain stimulation

Area of Science:

• Neuroscience
• Cognitive Science
• Neuroimaging

Background:

• Non-invasive brain stimulation (NIBS) targeting the dorsolateral prefrontal cortex (DLPFC) shows variable effects on working memory.
• Inter-subject anatomical variability is a potential factor influencing these inconsistent responses.

Purpose of the Study:

• To investigate the association between baseline cortical thickness in specific brain regions and working memory performance after NIBS.
• To determine if individual brain anatomy explains the heterogeneous effects of NIBS on working memory.

Main Methods:

• Secondary analysis of structural MRI data from healthy subjects who underwent transcranial direct current stimulation (tDCS), intermittent theta-burst stimulation (iTBS), and placebo.
• Working memory task performance was assessed post-NIBS, with regions of interest including bilateral DLPFC, medial prefrontal cortex, and posterior cingulate cortex.

Main Results:

• A significant negative association was found between bilateral DLPFC cortical thickness and reaction time for both tDCS and iTBS compared to placebo.
• Thicker DLPFC correlated with faster reaction times following tDCS and iTBS.
• A positive association was observed between iTBS, posterior cingulate cortex thickness, and working memory performance; no significant association was found for accuracy.

Conclusions:

• Baseline cortical thickness of the DLPFC is associated with working memory performance after tDCS and iTBS.
• Individual cortical thickness may partially explain the variability in NIBS effects on working memory.
• These findings highlight the role of neuroanatomy in modulating NIBS efficacy for cognitive enhancement.