Transcranial Infrared Laser Stimulation Enhances Emotion Regulation and Is Associated With Prefrontal Cortex Connectivity

Abstract

Emotion regulation depends on top-down prefrontal control of affective responses, and noninvasive prefrontal neuromodulation may augment this capacity. We tested whether enhancing prefrontal cortex function before cognitive reappraisal improves emotion regulation in healthy adults. Fifty participants were randomly assigned to receive transcranial infrared laser stimulation (TILS) or sham targeting the right prefrontal cortex before completing a negative-mood induction with instructed cognitive reappraisal. Subjective distress indexed emotional reactivity, and functional near-infrared spectroscopy measured prefrontal hemodynamics. TILS significantly attenuated sadness increases during instructed cognitive reappraisal versus sham. Resting-state prefrontal connectivity was unchanged between conditions. However, in the TILS group, pre-to-post connectivity increases were associated with reduced sadness reactivity, consistent with a preliminary prefrontal contribution. TILS did not alter mood immediately or at 2-week follow-up, supporting a capacity-enhancement account. No adverse effects were reported. TILS may enhance instructed cognitive reappraisal in healthy adults and has potential implications for future TILS interventions targeting clinical populations.