Gilman Jodi M, Lee Sang, Kuster John K, Lee Myung Joo, Kim Byoung Woo, van der Kouwe Andre, Blood Anne J, Breiter Hans C
Laboratory of Neuroimaging and Genetics Department of Psychiatry Massachusetts General Hospital (MGH) Charlestown Massachusetts 02129; Athinoula A. Martinos Center in Biomedical Imaging Department of Radiology Massachusetts General Hospital Charlestown Massachusetts 02129; Harvard Medical School Boston Massachusetts 02115.
Laboratory of Neuroimaging and Genetics Department of Psychiatry Massachusetts General Hospital (MGH) Charlestown Massachusetts 02129.
Brain Behav. 2016 Apr 22;6(5):e00459. doi: 10.1002/brb3.459. eCollection 2016 May.
Decades of research have demonstrated the importance of social influence in initiation and maintenance of drug use, but little is known about neural mechanisms underlying social influence in young adults who use recreational drugs.
To better understand whether the neural and/or behavioral response to social influence differs in young adults using illicit drugs, 20 marijuana-using young adults (MJ) aged 18-25, and 20 controls (CON) performed a decision-making task in the context of social influence, while they underwent functional magnetic resonance imaging scans. A priori analyses focused on the nucleus accumbens (NAc), with post hoc analyses in the rest of the striatum. In this task, participants could choose to either follow or go against group influence.
When subjects applied social information to response choice selection (independent of following or going against group influence), we observed activation in the middle striatum (caudate), in the MJ group only, that extended ventrally into the NAc. MJ users but not CON showed greater activation in the NAc but not the caudate while making choices congruent with group influence as opposed to choices going against group influence. Activation in the NAc when following social influence was associated with amount of drug use reported. In contrast, during the feedback phase of the task we observed significant NAc activation in both MJ and CON, along with dorsal caudate activation only in MJ participants. This NAc activation did not correlate with drug use.
This study shows that MJ users, but not CON, show differential brain activation across striatal subregions when applying social information to make a decision, following versus going against a group of peers, or receiving positive feedback. The current work suggests that differential neural sensitivity to social influence in regions such as the striatum may contribute to the development and/or maintenance of marijuana use.
数十年的研究已证明社会影响在药物使用的起始和维持过程中的重要性，但对于使用消遣性药物的年轻成年人中社会影响背后的神经机制却知之甚少。
为了更好地理解对社会影响的神经和/或行为反应在使用非法药物的年轻成年人中是否存在差异，20名年龄在18至25岁的使用大麻的年轻成年人（MJ组）和20名对照组（CON组）在社会影响的背景下执行一项决策任务，同时接受功能磁共振成像扫描。先验分析聚焦于伏隔核（NAc），并对纹状体的其余部分进行事后分析。在这项任务中，参与者可以选择跟随或违背群体影响。
当受试者将社会信息应用于反应选择时（无论跟随还是违背群体影响），我们仅在MJ组中观察到纹状体中部（尾状核）的激活，该激活向腹侧延伸至NAc。在做出与群体影响一致而非违背群体影响的选择时，MJ使用者而非CON组在NAc而非尾状核中表现出更大的激活。跟随社会影响时NAc的激活与报告的药物使用量相关。相比之下，在任务的反馈阶段，我们在MJ组和CON组中均观察到显著的NAc激活，并且仅在MJ参与者中观察到背侧尾状核激活。这种NAc激活与药物使用无关。
本研究表明，在应用社会信息进行决策、跟随或违背一群同龄人或接受积极反馈时，MJ使用者而非CON组在纹状体亚区域表现出不同的脑激活。当前的研究表明，纹状体等区域对社会影响的不同神经敏感性可能有助于大麻使用的发展和/或维持。
