Utilizing tACS to enhance memory confidence and EEG to predict individual differences in brain stimulation efficacy

Area of Science:

• Neuroscience
• Cognitive Science
• Memory Research

Background:

• Theta and gamma oscillations are crucial for memory retrieval.
• Previous studies on oscillations and memory were correlational.
• Non-invasive brain stimulation (NIBS) offers a direct method to study these effects.

Purpose of the Study:

• To investigate the direct causal effects of theta and gamma brain oscillations on memory performance.
• To explore how transcranial alternating current stimulation (tACS) modulates memory accuracy and confidence.
• To determine if pre-existing electroencephalogram (EEG) measures can predict individual responses to NIBS.

Main Methods:

• Utilized transcranial alternating current stimulation (tACS) at theta (4 Hz) and gamma (50 Hz) frequencies, alongside sham stimulation.
• Administered tACS over frontoparietal regions during a source memory retrieval task.
• Employed linear regression models to analyze the impact of tACS on memory accuracy and confidence.

Main Results:

• Both theta and gamma tACS significantly altered memory confidence.
• Theta tACS appeared to lower the confidence threshold for retrieved information.
• Gamma tACS influenced the bias in memory confidence.

Conclusions:

• Externally modulating brain oscillations with tACS directly impacts memory confidence.
• Individual differences in tACS efficacy can be predicted by pre-stimulation EEG measures.
• EEG may serve as a valuable tool for personalizing NIBS interventions for memory enhancement.