动机是重度抑郁障碍的典型特征,是指个体表现出降低的为奖励而付出努力的意愿。然而,抑郁症患者在决定是否为自我与他人付出努力时的动机模式仍不清楚。
我们进行了一项功能性磁共振成像研究,并在亚阈值抑郁(SD)参与者(n=33)和健康对照(HC)(n=32)中采用了适应的奖励任务努力支出。这要求参与者在固定的低努力/低回报和可变的高努力/高回报选项之间进行选择,然后立即努力为自己或不熟悉的人获得相应的奖励。
与HC组相比,SD组左背前扣带皮质/背内侧前额叶皮质活动减弱,双侧前岛(AI),选择为自己努力时,右壳核-左背外侧前额叶皮质功能连接。此外,当选择为他人努力时,SD组在双侧AI中表现出更高的意愿和更大的激活。此外,这些脑激活和功能连接与自我报告的动机呈正相关.
这些研究结果表明,轻度抑郁状态的个体在基于努力的决策过程中动机发生了改变,特别是对他人有更高的动机。因此,这表明SD患者的动机行为和前额叶纹状体电路发生了改变,可以用来发现治疗目标并制定策略来解决由动机障碍引起的精神疾病。
Amotivation is a typical feature in major depressive disorders and refers to individuals exhibiting reduced willingness to exert effort for rewards. However, the motivation pattern when deciding whether to exert effort for self versus
others in people with depression remains unclear.
We conducted a functional magnetic resonance imaging study and employed an adapted Effort-Expenditure for Rewards Task in subthreshold depressive (SD) participants (n = 33) and healthy controls (HC) (n = 32). This required participants to choose between a fixed low-effort/low-reward and a variable high-effort/high-reward option, and then immediately exert effort to obtain corresponding rewards for themselves or for unfamiliar people.
Compared with the HC group, the SD group showed blunted activity in the left dorsal anterior cingulate cortex/dorsomedial prefrontal cortex, bilateral anterior insula (AI), and right putamen-left dorsolateral prefrontal cortex functional connectivity when choosing to exert effort for themselves. Additionally, the SD group exhibited increased willingness and greater activation in the bilateral AI when choosing to exert effort for
others. Furthermore, these brain activations and functional connectivity were positively related to self-reported motivation.
These findings show altered motivation during effort-based decision-making in individuals with the mild depressive state, particularly with higher motivation for
others. Thus, this suggests that motivational behaviors and prefrontal-striatal circuitry are altered in individuals with SD, which can be utilized to discover treatment targets and develop strategies to address mental illness caused by motivation disorders.