Transcranial Direct Current Stimulation Modulates Working Memory Maintenance Processes in Healthy Individuals

Area of Science:

• Neuroscience
• Cognitive Science
• Neuroimaging

Background:

• Transcranial direct current stimulation (tDCS) is used to modulate brain activity and cognitive functions.
• The precise neural mechanisms underlying tDCS effects on working memory remain unclear.
• Understanding tDCS effects on specific working memory subprocesses is crucial for interpreting behavioral outcomes.

Purpose of the Study:

• To investigate the neurophysiological effects of tDCS on working memory task-related spectral activity.
• To determine which specific subprocesses of working memory are affected by tDCS.
• To correlate neurophysiological changes with behavioral performance.

Main Methods:

• Reanalysis of EEG data from 100 healthy participants performing a 3-back task.
• Participants received either sham or active tDCS.
• Analysis of event-related spectral power and synchronization in specific frequency bands.

Main Results:

• Active tDCS significantly reduced frontal theta event-related synchronization (ERS) post-stimulation.
• Participants receiving active tDCS exhibited slower reaction times (RTs) compared to the sham group.
• No significant correlation was found between theta ERS and RTs or accuracy.

Conclusions:

• tDCS selectively disrupts frontal theta ERS, indicating an impact on working memory cognitive control and maintenance.
• The observed neurophysiological changes may explain the heterogeneous behavioral effects of tDCS.
• These findings provide insights into the neural basis of tDCS neuromodulation on cognitive functions.