Department of Psychology, University of Ottawa, Ottawa, ON, K1N 6N5, Canada.
Psychopharmacology (Berl). 2010 Jun;210(3):429-38. doi: 10.1007/s00213-010-1841-8. Epub 2010 Apr 20.
The effects of marijuana use on visuospatial working memory were investigated in 19-21-year-olds using functional magnetic resonance imaging (fMRI).
Participants were members of the Ottawa Prenatal Prospective Study, a longitudinal study that collected a unique body of information on participants from infancy to young adulthood including: prenatal drug history, detailed cognitive/behavioral performance, and current and past drug usage. This information allowed for the measurement of an unprecedented number of potentially confounding drug exposure variables including: prenatal marijuana, nicotine, alcohol, and caffeine exposure and offspring alcohol, marijuana, and nicotine use. Ten marijuana users and 14 nonusing controls performed a visuospatial 2-back task while fMRI blood oxygen level-dependent response was examined.
Despite similar task performance, marijuana users had significantly greater activation in the inferior and middle frontal gyri, regions of the brain normally associated with visuospatial working memory. Marijuana users also had greater activation in the right superior temporal gyrus, a region of the brain not typically associated with visuospatial working memory tasks.
These results suggest that marijuana use leads to altered neural functioning during visuospatial working memory after controlling for other prenatal and current drug use. This alteration appears to be compensated for by the recruitment of blood flow in additional brain regions. It is possible that this compensation may not be sufficient in more real-life situations where this type of processing is required and thus deficits may be observed. Awareness of these neural physiological effects of marijuana in youth is critical.
本研究使用功能磁共振成像（fMRI）技术，探讨了大麻使用对 19-21 岁人群视空间工作记忆的影响。
参与者为渥太华产前前瞻性研究（Ottawa Prenatal Prospective Study）的成员，这是一项纵向研究，从婴儿期到成年早期收集了参与者独特的身体信息，包括：产前药物史、详细的认知/行为表现以及当前和过去的药物使用情况。这些信息可以测量出大量潜在的混杂药物暴露变量，包括：产前大麻、尼古丁、酒精和咖啡因暴露以及后代的酒精、大麻和尼古丁使用情况。10 名大麻使用者和 14 名非使用者在进行视空间 2 -back 任务时接受 fMRI 血氧水平依赖反应检查。
尽管任务表现相似，但大麻使用者在额下回和中回的激活程度显著更高，这些区域是大脑中与视空间工作记忆相关的区域。大麻使用者在右侧颞上回的激活程度也更高，而该区域通常与视空间工作记忆任务无关。
这些结果表明，在控制其他产前和当前药物使用的情况下，大麻使用会导致视空间工作记忆期间的神经功能发生改变。这种改变似乎通过在其他大脑区域增加血流来补偿。在需要这种处理的更现实的情况下，这种补偿可能不足以弥补，因此可能会观察到缺陷。了解大麻对年轻人的这些神经生理影响至关重要。
