Department of Psychology, Faculty of Psychology and Education, University of Tehran, Tehran, Iran.
Department of Cognitive Psychology, Institute of Cognitive Sciences Studies (ICSS), Tehran, Iran.
Psychopharmacology (Berl). 2022 May;239(5):1441-1457. doi: 10.1007/s00213-021-06002-7. Epub 2021 Oct 25.
Episodic future thinking (EFT) is a cognitive function that allows individuals to imagine novel experiences that may happen in the future. Prior studies show that EFT is impaired in different groups of substance users. However, there is no evidence regarding the neurobiological mechanisms of EFT in cannabis users.
We aimed to compare brain activations of regular cannabis users and non-using controls during an EFT fMRI task. Exploratory analyses were also conducted to investigate the association between EFT and cannabis use variables (e.g., duration of use, age onset, frequency of use).
Twenty current cannabis users and 22 drug-naïve controls underwent an fMRI scanning session while completing a task involving envisioning future-related events and retrieval of past memories as a control condition. The EFT fMRI task was adapted from the autobiographical interview and composed of 20 auditory cue sentences (10 cues for past and 10 cues for future events). Participants were asked to recall a past or generate a future event, in response to the cues, and then rate their vividness after each response.
We found that cannabis users compared to non-user controls had lower activation within the cerebellum, medial and superior temporal gyrus, lateral occipital cortex, and occipital fusiform gyrus while envisioning future events. Cannabis users rated the vividness of past events significantly lower than non-users (P < 0.005). There were marginal group differences for rating the vividness of future events (P = 0.052). Significant correlations were also found between the medial and superior temporal gyrus activities and behavioral measures of EFT and episodic memory.
Cannabis users, compared to drug-naïve controls, have lower brain activation in EFT relevant regions. Thus, any attempts to improve aberrant EFT performance in cannabis users may benefit from EFT training.
情景式未来思维（EFT）是一种认知功能，使个体能够想象未来可能发生的新体验。先前的研究表明，不同物质使用者群体的 EFT 受损。然而，关于大麻使用者的 EFT 的神经生物学机制尚没有证据。
我们旨在比较经常使用大麻的个体和未使用者在 EFT fMRI 任务中的大脑激活情况。还进行了探索性分析，以研究 EFT 与大麻使用变量（例如，使用时间、发病年龄、使用频率）之间的关联。
20 名当前大麻使用者和 22 名药物-naive 对照者在进行 fMRI 扫描的同时完成了一项任务，该任务包括想象未来相关事件和检索过去记忆作为对照条件。EFT fMRI 任务改编自自传访谈，由 20 个听觉提示句子组成（10 个提示过去事件，10 个提示未来事件）。参与者被要求回忆过去或生成未来事件，以响应提示，然后在每次响应后对其生动度进行评分。
我们发现，在想象未来事件时，大麻使用者与非使用者对照者相比，在小脑、内侧和上颞叶、外侧枕叶皮质和枕叶梭状回的激活水平较低。大麻使用者对过去事件的生动度评分明显低于非使用者（P<0.005）。对未来事件的生动度评分存在边际组间差异（P=0.052）。内侧和上颞叶的活动与 EFT 和情景记忆的行为测量之间也存在显著相关性。
与药物-naive 对照者相比，大麻使用者在 EFT 相关区域的大脑激活水平较低。因此，任何试图改善大麻使用者异常 EFT 表现的尝试都可能受益于 EFT 训练。
