Tracking emotional interference over time: Differential effects of dorsolateral and ventromedial prefrontal stimulation

Although a substantial body of evidence has demonstrated that emotional interference affects cognitive performance, relatively little is known about its temporal evolution and the respective brain regions underlying its regulation. The present study investigated the temporal dynamics of emotional interference and the contribution of prefrontal regions involved in its regulation. Forty-eight participants completed a 2-back task and a Set-switching task under neutral and negative emotional conditions while receiving sham, dorsolateral prefrontal cortex (dlPFC), or ventromedial prefrontal cortex (vmPFC) stimulation. Stimulation was administered either online during task performance or after a 5 min pre-task period. Consistent with previous findings, negative emotions impaired executive performance, particularly during high-demand updating conditions. Critically, time-resolved analyses revealed that emotional interference evolved dynamically throughout task performance and was differentially modulated by prefrontal stimulation. The most consistent stimulation effects emerged after approximately 10 minutes of cumulative stimulation exposure and varied as a function of the stimulation site, executive-control demands, and stimulation timing. Notably, online stimulation produced more consistent modulation than pre-task stimulation. Together, these findings indicate that both emotional interference and its neuromodulation are dynamic processes. More broadly, they suggest that the contribution of prefrontal control systems to emotion-cognition interactions may be better understood through their temporal evolution rather than through static measures of performance alone.