Excitatory brain stimulation over the left dorsolateral prefrontal cortex enhances voluntary distraction in depressed patients

BACKGROUND: While implicit distraction could ameliorate negative feelings in patients with major depressive disorders (MDD), it remains unclear whether patients could benefit from explicit, voluntary distraction. Meanwhile, though the dorsolateral prefrontal cortex (DLPFC) is established as a crucial brain region involved in attentional control, the causal relationship between the DLPFC and voluntary distraction is unexplored in patients. METHODS: Combing explicit distraction and transcranial magnetic stimulation (TMS), this study investigated whether TMS-activated DLPFC facilitates voluntary distraction in MDD patients. Eighty patients diagnosed with current MDD underwent either active (n = 40) or sham (n = 40) TMS sessions, followed by receiving negative social feedback from other patients, during which they were requied to use distraction strategy to down-regulate their painful feelings. Electroencephalogram was recorded during the task. RESULTS: Both the subjective emotional rating and the amplitude of late positive potential showed that depressed patients successfully down-regulate their negative emotions via voluntary distraction, and the TMS-activated left DLPFC produced a larger benefit of emotion regulation compared to the sham TMS group. Results also revealed that while emotion regulation effect was negatively associated with depressive symptoms in the sham TMS group, this correlation was largely diminished when patients' left DLPFC was activated by TMS during the voluntary distraction. CONCLUSIONS: These findings demonstrated that distraction is valuable for emotion regulation in MDD patients and they could be beneficial in voluntary distraction by activating their left DLPFC using neural modulation techniques. This study has valuable implications for clinical treatement of emotional dysregulation in MDD patients.