Perturbation of the right prefrontal cortex disrupts interference control

Area of Science:

• Cognitive Neuroscience
• Neuropsychology
• Brain Stimulation

Background:

• Cognitive interference resolution is crucial for daily functioning.
• The Stroop task measures interference, with performance influenced by trial history (sequence effects).
• Previous studies implicated the prefrontal cortex in Stroop task performance, but causal roles remain unclear.

Purpose of the Study:

• To investigate the causal relevance of the left and right prefrontal cortex in processing cognitive interference.
• To determine the specific role of these prefrontal regions in Stroop task performance and sequence effects.

Main Methods:

• Twenty-five healthy participants underwent three sessions of online repetitive transcranial magnetic stimulation (rTMS).
• rTMS was applied over the left dorsolateral prefrontal cortex, right dorsolateral prefrontal cortex, or sham stimulation over the vertex.
• Participants completed a verbal-response Stroop task during each stimulation session.

Main Results:

• rTMS over the right dorsolateral prefrontal cortex selectively disrupted the Stroop sequence effect (congruency sequence effect; CSE).
• This disruption was specific to sequential interference processing, as ongoing Stroop performance was unaffected.
• rTMS over the left prefrontal cortex did not significantly alter Stroop sequence effects compared to sham.

Conclusions:

• The right dorsolateral prefrontal cortex plays a functionally relevant role in processing cognitive interference, specifically sequence effects.
• Findings suggest process-specific lateralization within the prefrontal cortex for interference control.
• This study provides novel insights into the neurophysiological basis of Stroop task performance and prefrontal cortex function in interference resolution.