Remember NIBS? tACS improves memory performance in elders with subjective memory complaints.

Area of Science:

• Neuroscience
• Cognitive Psychology
• Neuromodulation

Background:

• Subjective memory complaints (SMC) are linked to Alzheimer's disease.
• Episodic memory, a key component of SMC, is crucial for cognitive health in aging.
• Non-invasive brain stimulation techniques are emerging as potential interventions for cognitive decline.

Purpose of the Study:

• To investigate the efficacy of theta frequency (6 Hz) transcranial alternating current stimulation (tACS) on the medial prefrontal cortex (mPFC).
• To assess the impact of tACS on improving episodic memory in individuals experiencing SMC.
• To explore the neurophysiological changes associated with tACS in this population.

Main Methods:

• A double-blind, randomized, sham-controlled parallel study.
• Sixteen participants with SMC received either active or sham theta tACS targeting the mPFC.
• Electroencephalography (EEG) and the Rey Auditory Verbal Learning Test (RAVLT) were used for data collection.

Main Results:

• Active theta tACS significantly improved episodic memory performance compared to sham stimulation.
• EEG analysis showed decreased theta power, reduced current source density (CSD) across several brain regions, and decreased phase synchronization.
• A correlation was found between delayed recall performance and theta band CSD in the left inferior gyrus.

Conclusions:

• Theta tACS applied to the mPFC demonstrates potential as a therapeutic intervention for enhancing event memory in individuals with SMC.
• The observed improvements are associated with modulation of neural activity in frontal and temporal brain regions.
• This study supports tACS as a promising non-invasive strategy for cognitive enhancement in aging populations.