Modulating oscillatory brain activity correlates of behavioral inhibition using transcranial direct current...

Area of Science:

• Neuroscience
• Electrophysiology
• Brain Stimulation

Background:

• Transcranial direct current stimulation (tDCS) is known to induce behavioral changes.
• Recent research explores tDCS's cortical modulation effects.
• Previous studies linked right inferior frontal gyrus (rIFG) tDCS to behavioral inhibition, but electrophysiological underpinnings were unclear.

Purpose of the Study:

• To investigate the electrophysiological changes induced by a specific tDCS montage.
• To evaluate neuronal oscillation alterations following anodal tDCS over the rIFG and cathodal tDCS over the left orbitofrontal cortex (lOFC).
• To analyze spectral power changes in EEG recordings post-stimulation.

Main Methods:

• A single-blind, placebo-controlled, cross-over trial involving healthy subjects.
• Real and sham tDCS sessions (15 min, 1.5 mA) with anodal rIFG and cathodal lOFC stimulation.
• Resting electroencephalography (EEG) recordings collected for 15 minutes after each tDCS session.

Main Results:

• A significant and selective decrease in theta band power was observed.
• This theta power reduction was localized to the rIFG (anode) area.
• No significant changes were found in other frequency bands or in the lOFC (cathode) area.

Conclusions:

• This study demonstrates for the first time that tDCS over the rIFG can modulate oscillatory activity measured by EEG.
• The findings specifically document a reduction in theta band activity with this tDCS montage.
• Results may explain previous behavioral findings and suggest potential applications for ADHD patients targeting theta activity for cognitive control improvement.