Transcranial Alternating Current Stimulation at the Individual Alpha Frequency Shows Potential Value in Improving...

Area of Science:

• Neuroscience
• Cognitive Science
• Biomedical Engineering

Background:

• Working memory (WM) is crucial for cognitive functions.
• Transcranial alternating current stimulation (tACS) is a non-invasive brain stimulation technique.
• Understanding the neural mechanisms of tACS on WM is essential.

Purpose of the Study:

• To investigate the effect of tACS at the individual alpha frequency (IAF) on the left posterior parietal cortex (PPC) on working memory (WM).
• To combine behavioral and electroencephalography (EEG) techniques to assess WM performance and neural activity.
• To clarify the promoting effect of IAF-tACS on WM.

Main Methods:

• A single-blind, randomized, crossover, controlled trial with three groups: IAF, IAF-1, and sham.
• WM was assessed using the n-back task.
• EEG signals were collected simultaneously to analyze event-related potentials (ERPs) and event-related desynchronization/synchronization (ERS/ERD).

Main Results:

• Participants showed improved WM performance post-stimulation, with decreased reaction time and increased d' values.
• IAF-tACS significantly increased P200 and P300 amplitudes in the frontocentral region during the 3-back task.
• A negative correlation was found between P300 amplitude changes and reaction time changes in the IAF group.

Conclusions:

• IAF-tACS specifically enhances high-load WM performance in healthy individuals.
• The enhancement is associated with increased P300 amplitude in the frontocentral region.
• This suggests a novel strategy for cognitive regulation, with potential for future clinical applications.