Increasing working memory capacity with theta transcranial alternating current stimulation (tACS).

Area of Science:

• Neuroscience
• Cognitive Psychology
• Brain Stimulation

Background:

• Working memory (WM) is crucial for cognitive functions.
• Understanding the neural mechanisms of WM capacity is an ongoing research area.
• Non-invasive brain stimulation techniques offer potential for cognitive enhancement.

Purpose of the Study:

• To investigate the causal effect of transcranial alternating current stimulation (tACS) on working memory (WM) storage capacity.
• To determine the influence of tACS targeting different brain regions (parietal vs. frontal) on WM.
• To explore the neurophysiological correlates of tACS-induced changes in WM.

Main Methods:

• Sham/verum tACS at individually determined theta frequency applied to left parietal (P3) or frontal (F3) areas.
• 24 participants completed a task measuring attention scope post-stimulation.
• Electroencephalogram (EEG) recorded to analyze event-related potentials (ERPs).

Main Results:

• Verum tACS over the left parietal area significantly increased WM storage capacity compared to sham stimulation.
• No significant effect on WM capacity was observed with tACS targeting the left frontal area.
• Increased WM capacity correlated with a decrease in event-related potential (ERP) P300 latency in the left hemisphere.

Conclusions:

• Left parietal theta frequency tACS causally enhances WM storage capacity.
• Theta oscillations in the left parietal region are critically involved in WM storage.
• Targeted neurostimulation offers a method to modulate cognitive functions like WM.