Lasting enhancements in neural efficiency by multi-session transcranial direct current stimulation during working...

Area of Science:

• Neuroscience
• Cognitive Science
• Neuromodulation

Background:

• The neural mechanisms underlying sustained cognitive enhancement from combined transcranial direct current stimulation (tDCS) and working memory training (WMT) are not fully understood.
• Investigating long-term neurophysiological changes is crucial for optimizing brain stimulation protocols.

Purpose of the Study:

• To explore the lasting neurophysiological effects of multi-session anodal high-definition (HD)-tDCS combined with working memory training (WMT).
• To examine how HD-tDCS over the left dorsolateral prefrontal cortex (dlPFC) influences brain activity during working memory tasks.

Main Methods:

• Thirty-four healthy young adults participated in a randomized, sham-controlled study.
• Participants underwent ten daily sessions of either active or sham HD-tDCS paired with a challenging WMT protocol.
• Task-related electroencephalography (EEG) was recorded during pre-test, post-test (1 day after training), and follow-up (3 weeks after training) assessments.

Main Results:

• Multi-session HD-tDCS significantly amplified the behavioral benefits of WMT.
• The active tDCS group exhibited enhanced theta, alpha, beta, and gamma oscillations post-training.
• A significant increase in the P300 response was observed in the active group three weeks after the final session.

Conclusions:

• Anodal HD-tDCS applied to the left dlPFC during multi-session WMT enhances behavioral improvements.
• This combined approach facilitates sustained neural efficiency related to working memory.