Worldwide, cannabis is one of the most widely used psychoactive substances and cannabis use has been implicated in poorer performance in several cognitive domains, including working memory (WM). However, the neural mechanisms underlying these WM decrements are not well understood and the current study investigated the association of cannabis involvement with WM performance and associated neural activation in the Human Connectome Project (N = 1038). Multiple indicators of cannabis involvement were examined in relation to behavioral performance and brain activity in a visual N-back task using functional magnetic resonance imaging. A positive urine drug screen for tetrahydocannabinol (THC+ status), the principal psychoactive constituent in cannabis, was associated with worse WM performance and differential brain response in areas previously linked to WM performance. Furthermore, decreases in blood-activation-level-dependent (BOLD) signal in WM task-positive brain regions and increases in task-negative regions mediated the relationship between THC+ status and WM performance. In contrast, WM performance and BOLD response during the N-back task were not associated with total lifetime cannabis use, age of first use, or other indicators of involvement, suggesting that the effects of cannabis on WM were short-term residual effects, rather than long-term persistent effects. These findings elucidate differential influences of cannabis involvement on neurocognition and have significant potential implications for occupational performance in diverse settings.

中文翻译：

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尿液中的四氢大麻酚与较差的工作记忆表现和相关大脑活动的改变有关。

在世界范围内，大麻是使用最广泛的精神活性物质之一，大麻的使用与包括工作记忆（WM）在内的多个认知领域的表现较差有关。然而，这些 WM 减少背后的神经机制尚不清楚，目前的研究调查了大麻参与与 WM 表现以及人类连接组项目 (N = 1038) 中相关神经激活的关系。使用功能磁共振成像检查视觉 N-back 任务中大麻参与的多项指标与行为表现和大脑活动的关系。尿液中四氢大麻酚（THC+状态）（大麻中的主要精神活性成分）药物筛查呈阳性，与较差的 WM 表现以及先前与 WM 表现相关的区域的大脑反应差异相关。此外，WM 任务阳性大脑区域中血液激活水平依赖性 (BOLD) 信号的减少和任务阴性区域的增加介导了 THC+ 状态和 WM 表现之间的关系。相比之下，N-back 任务期间的 WM 表现和 BOLD 反应与总生命周期大麻使用、首次使用年龄或其他参与指标无关，这表明大麻对 WM 的影响是短期残留效应，而不是比长期持续的影响。这些发现阐明了大麻参与对神经认知的不同影响，并对不同环境中的职业表现具有重大的潜在影响。