Modulating positive self-referential processing by 40 Hz tACS in individuals with subthreshold depression: A...

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Science

Background:

• Positive self-evaluation is crucial for mental well-being, yet methods to enhance it are underexplored.
• Gamma-frequency (40 Hz) transcranial alternating current stimulation (tACS) shows promise in improving emotion regulation and memory.
• The medial prefrontal cortex (mPFC) is vital for self-referential processing.

Purpose of the Study:

• To investigate if 40 Hz tACS applied to the mPFC can enhance positive self-evaluation.
• To examine this effect specifically in individuals with subthreshold depression.
• To test the hypothesis that 40 Hz stimulation improves self-evaluation.

Main Methods:

• A double-blind, randomized, sham-controlled study involved 60 participants with subthreshold depression.
• Participants received either 20 minutes of 40 Hz tACS over the mPFC or sham stimulation.
• The Self-Referential Encoding Task (SRET) was used to assess endorsement and recall of positive and negative personality traits before and after stimulation.

Main Results:

• A significant interaction was observed between stimulation group, depressive symptoms, and trait valence.
• Participants receiving 40 Hz tACS showed increased endorsement and recall of positive personality traits compared to the sham group.
• This effect was particularly significant among individuals with higher baseline depressive symptoms (p < 0.05).

Conclusions:

• 40 Hz gamma tACS over the mPFC effectively enhanced positive self-referential processing in individuals with subthreshold depression.
• The positive impact on self-evaluation was more pronounced in those with greater depressive symptoms.
• Gamma-frequency stimulation presents a potential therapeutic strategy for improving positive self-evaluation in depression.