Triangular Wave tACS Improves Working Memory Performance by Enhancing Brain Activity in the Early Stage of Encoding

Area of Science:

• Neuroscience
• Cognitive Psychology

Background:

• Working memory involves encoding, maintenance, and retrieval.
• Transcranial alternating current stimulation (tACS) can modulate working memory.
• The impact of current change rate in tACS on working memory is not well understood.

Purpose of the Study:

• To investigate the effects of triangular wave tACS and sinusoidal wave tACS on working memory performance and brain activity.
• To compare the impact of different tACS current change rates on cognitive processes.

Main Methods:

• Randomized, single-blind study with 81 participants.
• Three groups received triangular wave tACS, sinusoidal wave tACS, or sham stimulation.
• Participants performed n-back tasks with electroencephalogram (EEG) recordings.

Main Results:

• All tACS types improved working memory performance (accuracy, response time) compared to baseline.
• Triangular wave tACS enhanced non-target information processing efficiency and early encoding brain network connectivity.
• Sinusoidal wave tACS increased theta power in the central frontal region during later encoding.

Conclusions:

• Triangular wave tACS significantly improves working memory efficiency through enhanced brain network connectivity in early encoding.
• Sinusoidal wave tACS may play a role in late-stage information processing by modulating theta power.
• Findings offer insights into tACS mechanisms for modulating working memory.