背景:动机是重度抑郁症(MDD)的典型特征,这就降低了努力的意愿。背外侧前额叶皮层(DLPFC)是目标导向行动的重要结构,因此是调节努力动机的潜在目标。然而,目前尚不清楚该干预措施对MDD患者是否有效.
方法:我们采用经颅磁刺激(TMS),计算模型和事件相关电位(ERP),以揭示左侧DLPFC与MDD中努力奖励动机之间的因果关系。50名患者接受了主动和假TMS治疗,每个人都执行奖励任务的努力支出,在此期间,参与者在低努力/低回报和高努力/高回报选项之间进行选择和实施。
结果:在DLPFC促进会议期间,患者表现出更大的努力争取奖励的意愿,与假会议相比。他们也有一个趋势,在更大的P3振幅的积极关注所选择的选项,在准备努力锻炼期间更大的CNV,和更大的SPN在预期高回报。此外,虽然努力选择的行为指数与假手术中的抑郁严重程度呈负相关,这种相关性在主动刺激阶段减弱.
结论:这些发现提供了行为,计算,和左侧DLPFC关于努力奖励动机的神经证据。简化的DLPFC改善了做出决策后的运动准备和价值预期,尤其是在MDD中付出巨大努力的回报。便利的DLPFC在成本效益权衡过程中也具有增强积极注意力的潜在功能。这种神经调节效应为改善临床动机提供了潜在的治疗方法。
BACKGROUND: Amotivation is a typical feature in major depressive disorder (MDD), which produces reduced willingness to exert
effort. The dorsolateral prefrontal cortex (DLPFC) is a crucial structure in goal-directed actions and therefore is a potential target in modulating effortful motivation. However, it remains unclear whether the intervention is effective for patients with MDD.
METHODS: We employed transcranial magnetic stimulation (TMS), computational modelling and event-related potentials (ERPs) to reveal the causal relationship between the left DLPFC and motivation for effortful rewards in MDD. Fifty patients underwent both active and sham TMS sessions, each followed by performing an Effort-Expenditure for Rewards Task, during which participants chose and implemented between low-
effort/low-reward and high-
effort/high-reward options.
RESULTS: The patients showed increased willingness to exert
effort for rewards during the DLPFC facilitated session, compared with the sham session. They also had a trend in larger P3 amplitude for motivated attention toward chosen options, larger CNV during preparing for
effort exertion, and larger SPN during anticipating a high reward. Besides, while behavior indexes for effortful choices were negatively related to depression severity in the sham session, this correlation was weakened in the active stimulation session.
CONCLUSIONS: These findings provide behavioral, computational, and neural evidence for the left DLPFC on effortful motivation for rewards. Facilitated DLPFC improves motor preparation and value anticipation after making decisions especially for highly effortful rewards in MDD. Facilitated DLPFC also has a potential function in enhancing motivated attention during cost-benefit trade-off. This neuromodulation effect provides a potential treatment for improving motivation in clinics.