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Updated: Jun 3, 2025
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Transcranial Direct Current Stimulation tDCS for Memory Enhancement
Published on: September 18, 2021
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Baseline gray matter volume associates with working memory performance after prefrontal transcranial direct current
Oscar Martin-Garcia1, Pedro Henrique Rodrigues da Silva2, Stefanie De Smet3
1Department of Personality, Evaluation and Clinical Psychology, Complutense University of Madrid, Madrid, Spain.
Behavioural Brain Research
|January 6, 2025
Summary
Brain structure influences working memory responses to transcranial direct current stimulation (tDCS). Individual gray matter volume impacts performance, especially with lower tDCS intensities, highlighting variability in tDCS effectiveness.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Neuromodulation
Background:
- Working memory is essential for daily functioning and frequently impaired in neuropsychiatric disorders.
- Transcranial direct current stimulation (tDCS) attempts to enhance working memory yield inconsistent results, potentially due to individual differences.
- Inter-individual variability in brain structure may influence the efficacy of tDCS for working memory enhancement.
Purpose of the Study:
- To investigate the association between baseline regional brain volume and working memory performance after tDCS.
- To explore how different tDCS intensities (1.5 mA and 3 mA) and task types (emotional vs. non-emotional) interact with brain structure.
- To understand individual variability in response to tDCS over the dorsolateral prefrontal cortex (dlPFC).
Main Methods:
- Healthy participants underwent three bilateral tDCS protocols (sham, 1.5 mA, 3 mA) over the dlPFC in a within-subjects design.
- Baseline gray matter volumes of the dlPFC, medial PFC (mPFC), and posterior cingulate cortex (PCC) were quantified.
- Participants completed emotional and non-emotional 3-back tasks to assess working memory performance post-stimulation.
Main Results:
- No significant association was found between working memory performance and gray matter volume after sham tDCS.
- Larger baseline cortical volumes correlated with slower reaction times and lower accuracy on the non-emotional task at 1.5 mA tDCS.
- Significant associations between reaction time and brain volume were observed for the emotional task at 3 mA tDCS, specifically involving the left dlPFC and right PCC.
Conclusions:
- Baseline gray matter volume is associated with individual working memory performance following tDCS.
- The effectiveness of tDCS is influenced by methodological factors, including current intensity and the specific cognitive task.
- Further research is needed to elucidate the mechanisms underlying tDCS effects and individual variability.
