Repetitive TMS over the left dorsolateral prefrontal cortex modulates the error positivity: An ERP study.

Error processing is a critical step towards an efficient adaptation of our behavior to achieve a goal. Little research has been devoted to investigate the contribution of the dorsolateral prefrontal cortex (DLPFC) in supporting error processing. In this study, the causal relationship of the DLPFC in error commission was examined by means of a repetitive transcranial magnetic stimulation protocol (rTMS). Specifically, the effects of an inhibitory protocol were assessed by examining the electroencephalographic signal recorded during the execution of a Go/No-Go task. To this aim, a group of 15 healthy young participants performed a three-session study. At each session, either the right DLPFC, the left DLPFC, or the Vertex (control site) were stimulated, for 20 min at 1 Hz. Immediately after the stimulation, participants performed the task. Although no behavioral effects of rTMS emerged, the analysis of event-related electric potentials (ERPs) revealed that the amplitude of a positive potential evoked by error commission, the error positivity (Pe), was reduced after the stimulation of the left DLPFC. On the contrary, the earlier error-related negativity component (ERN) was not affected. These results revealed that the left DLPFC intervenes at later stages of error-related processes. We could speculate that its role is specifically linked to error awareness.