Abstract: The frontal P3 component is a reliable electrophysiological marker of the engagement of prefrontal cognitive control resources. In previous studies, frontal P3 amplitude has typically been regarded as a neural correlate of early-stage resource recruitment during executive control tasks, including emotion regulation. However, this correlational interpretation leaves an important question unresolved: whether actively changing frontal P3 amplitude can causally influence the executive control processes that support emotion regulation. To address this question, the present study used neurofeedback (NF) training to modulate frontal P3 amplitude and examined its potential causal role in emotion regulation.
Sixty-seven participants were randomly assigned to either an experimental group, which was trained to upregulate frontal P3 amplitude (n = 34), or a control group, which was trained to downregulate frontal P3 amplitude (n = 33). All participants completed an emotion regulation task before and after NF training. During the task, participants were instructed to use cognitive reappraisal to reinterpret negative emotional stimuli and reduce their emotional impact. Emotion regulation effectiveness was assessed using both subjective ratings of negative emotion and the parietal late positive potential (LPP), an electrophysiological index of emotional experience intensity.
Compared with the pre-training baseline, participants in the experimental group successfully increased frontal P3 amplitude through NF training. This training effect indicated that they were able to more effectively recruit the executive control function indexed by frontal P3. Critically, after NF training, the experimental group showed improved emotion regulation effectiveness, as reflected by significant reductions in both self-reported negative emotion and parietal LPP amplitude during emotion regulation. In contrast, the control group showed the opposite pattern. After training, frontal P3 amplitude during emotion regulation decreased, and emotion regulation effectiveness was reduced, suggesting that weakening the neural activity indexed by frontal P3 impaired the regulatory process.
Further analyses indicated that the beneficial effect of P3-NF training on emotion regulation was primarily achieved by increasing frontal P3 amplitude during cognitive reappraisal itself. This finding suggests that frontal P3 is not merely a passive neural marker of prefrontal resource engagement, but may reflect an executive control process that directly contributes to successful emotion regulation. Unlike previous correlational neuroimaging studies, we utilized ERP-NF neuromodulation technology to causally demonstrate that the prefrontal cognitive control resources indexed by frontal P3 constitute the causal neural foundation for the early stages of emotion regulation. These findings provide novel insights into the neurophysiological mechanisms underlying emotion regulation and offer a new approach for precise, non-invasive brain modulation to treat prefrontal executive control deficits in clinical populations.

Key words: emotion regulation, neurofeedback, cognitive reappraisal, frontal P3, late positive potential