Individualized tDCS modeling predicts functional connectivity changes within the working memory network in older
Aprinda Indahlastari1, Alejandro Albizu2, Jessica N Kraft2
1Center for Cognitive Aging and Memory, McKnight Brain Institute, University of Florida, Gainesville, FL, USA; Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, USA.
Brain Stimulation
|August 9, 2021
Summary
This study shows that the electrical current applied to the left dorsolateral prefrontal cortex (DLPFC) in older adults is linked to improved working memory network connectivity. These findings support using transcranial direct current stimulation (tDCS) to enhance cognitive function.
Area of Science:
- Neuroscience
- Cognitive Science
- Biomedical Engineering
Background:
- Working memory decline is common in aging, linked to prefrontal cortex (PFC) changes.
- Previous research showed transcranial direct current stimulation (tDCS) alters functional connectivity in the working memory network.
- This study is the first to use individualized models to predict tDCS effects on functional connectivity in older adults.
Purpose of the Study:
- To predict changes in functional connectivity using individualized finite element models of older adults' brains.
- To correlate electrical current density in specific PFC regions with functional connectivity metrics during tDCS.
- To investigate the relationship between tDCS parameters and working memory network activity.
Main Methods:
- Constructed individualized head models from 15 older adults' MRI scans.
- Segmented models into 11 tissue types and included electrodes.
- Correlated computed current densities in left DLPFC and VLPFC with functional connectivity (beta values) during active and sham tDCS.
Main Results:
- Found significant positive correlations between current density and functional connectivity in the left DLPFC during active tDCS (R²=0.523 for max J, R²=0.367 for median J, p<0.05).
- No significant correlations were observed during sham stimulation or in the left VLPFC for either stimulation condition.
- Current within the left DLPFC positively correlated with functional connectivity changes between left DLPFC and VLPFC.
Conclusions:
- The amount of electrical current in the left DLPFC is positively associated with tDCS-induced functional connectivity changes.
- These findings validate the use of individualized tDCS models for predicting brain stimulation effects.
- Future research should expand participant numbers to further validate these predictive models for the working memory network.
