Brassard Sarah L, Dosanjh Jadyn, Cooper Jessica, Weber Jochen, Zald David, MacKillop James, Balodis Iris M
Department of Psychiatry and Behavioural Neurosciences, McMaster University, 1280 Main Street West, Hamilton, ON, L8S 4L8, Canada.
Peter Boris Centre for Addictions Research, St. Joseph's Healthcare Hamilton, 100 West 5 th Street, Hamilton, ON, Canada.
Cogn Affect Behav Neurosci. 2025 Jun 17. doi: 10.3758/s13415-025-01308-x.
Low motivation for noncannabis rewards is a common clinical feature of cannabis use disorder (CUD), yet its underlying neurobiological mechanisms remain largely unknown. This study applied a sequential effort-based decision-making task during functional magnetic resonance imaging to quantify motivation and test for potential neurofunctional differences during prospective effort/reward encoding (Cue1), integration of effort and reward cues (Cue2), and choice behaviour in individuals with CUD (n = 21) and healthy controls (HCs) (n = 20). Behavioural in-scanner results demonstrated that participants in both groups made significantly fewer high-effort choices as effort levels increased on the task, yet they selected significantly more high-reward choices as reward magnitude increased. At the neural level, the CUD group showed decreased ventromedial prefrontal cortex activity, as well as reduced activity in the culmen, posterior cingulate, and superior temporal gyrus during the encoding of prospective effort and reward cues (Cue1) respectively, compared with controls. Conversely, the CUD group showed increased parietal lobule, superior temporal gyrus, fusiform gyrus, middle occipital gyrus, cingulate gyrus, and claustrum activity during the integration phase of the task (Cue2) relative to controls. Exploratory correlations revealed that bilateral ventral striatum activity during prospective effort cues was associated with the proportion of accepted high-effort and high-reward trials, predominantly driven by the CUD group. Altogether, these findings indicate fronto-striatal but also posterior cortical processing alterations during prospective signaling and during effort-reward information integration. By temporally disconnecting effort expenditure from reward magnitude, the current findings shed light on how these constructs independently and simultaneously influence dysregulated effortful goal-directed choice behaviour in CUD.
对非大麻类奖励缺乏动机是大麻使用障碍（CUD）的常见临床特征，但其潜在的神经生物学机制仍 largely 未知。本研究在功能磁共振成像期间应用了一项基于顺序努力的决策任务，以量化动机，并测试 CUD 患者（n = 21）和健康对照者（HCs，n = 20）在前瞻性努力/奖励编码（提示 1）、努力和奖励线索整合（提示 2）以及选择行为过程中的潜在神经功能差异。扫描过程中的行为结果表明，随着任务中努力水平的增加，两组参与者做出的高努力选择显著减少，但随着奖励幅度的增加，他们选择的高奖励选择显著增多。在神经层面，与对照组相比，CUD 组在前瞻性努力和奖励线索编码（提示 1）期间腹内侧前额叶皮质活动减少，同时山顶、后扣带回和颞上回的活动分别减少。相反，与对照组相比，CUD 组在任务整合阶段（提示 2）顶叶小叶、颞上回、梭状回、枕中回、扣带回和屏状核的活动增加。探索性相关性分析显示，前瞻性努力线索期间双侧腹侧纹状体活动与接受的高努力和高奖励试验的比例相关，主要由 CUD 组驱动。总之，这些发现表明在前瞻性信号传递以及努力 - 奖励信息整合过程中，额 - 纹状体以及后皮质处理存在改变。通过在时间上使努力支出与奖励幅度脱节，当前研究结果揭示了这些结构如何独立且同时影响 CUD 中失调的有目的努力选择行为。
