EEG mean frequency changes in healthy subjects during prefrontal transcranial direct current stimulation

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Electrophysiology

Background:

• Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique.
• Electroencephalography (EEG) measures electrical activity in the brain.
• Prefrontal cortex plays a key role in executive functions.

Purpose of the Study:

• To evaluate changes in EEG mean frequency induced by prefrontal tDCS.
• To investigate the influence of tDCS electrode montage on these EEG changes.
• To explore potential asymmetric functional organization of the prefrontal cortex.

Main Methods:

• Eight healthy volunteers participated in a pilot study.
• tDCS was applied for 15 minutes during EEG recording.
• Six different tDCS montages (unipolar and bipolar) and a sham condition were tested.
• EEG power spectra were analyzed before, during, and after tDCS.

Main Results:

• EEG mean frequency (brain rate, fb) significantly changed during and after tDCS.
• Leftward DC dipole stimulation (anodal left) increased fb.
• Rightward DC dipole stimulation (anodal right) decreased fb.
• Stimulation effects were opposite but equal in magnitude, irrespective of gender.

Conclusions:

• Prefrontal tDCS induces significant and persistent changes in EEG mean frequency.
• The direction of the tDCS current influences EEG activity, suggesting asymmetric prefrontal cortex organization.
• tDCS effects on EEG mean frequency are independent of gender.