title: Variable activation in striatal subregions across components of a social influence task in young adult cannabis users.
abstract: 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.
authors.affiliation: 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.
authors.forename: Jodi M
authors.initials: JM
authors.lastname: Gilman
authors.affiliation: Laboratory of Neuroimaging and Genetics Department of Psychiatry Massachusetts General Hospital (MGH) Charlestown Massachusetts 02129.
authors.forename: Sang
authors.initials: S
authors.lastname: Lee
authors.affiliation: Laboratory of Neuroimaging and Genetics Department of Psychiatry Massachusetts General Hospital (MGH) Charlestown Massachusetts 02129; Mood and Motor Control Laboratory Massachusetts General Hospital Charlestown Massachusetts 02129.
authors.forename: John K
authors.initials: JK
authors.lastname: Kuster
authors.affiliation: Laboratory of Neuroimaging and Genetics Department of Psychiatry Massachusetts General Hospital (MGH) Charlestown Massachusetts 02129; Warren Wright Adolescent Center Department of Psychiatry and Behavioral Sciences Northwestern University Feinberg School of Medicine Chicago Illinois 06011.
authors.forename: Myung Joo
authors.initials: MJ
authors.lastname: Lee
authors.affiliation: Laboratory of Neuroimaging and Genetics Department of Psychiatry Massachusetts General Hospital (MGH) Charlestown Massachusetts 02129; Warren Wright Adolescent Center Department of Psychiatry and Behavioral Sciences Northwestern University Feinberg School of Medicine Chicago Illinois 06011.
authors.forename: Byoung Woo
authors.initials: BW
authors.lastname: Kim
authors.affiliation: Athinoula A. Martinos Center in Biomedical Imaging Department of Radiology Massachusetts General Hospital Charlestown Massachusetts 02129; Harvard Medical School Boston Massachusetts 02115; Laboratory for Computational Neuroimaging Department of Radiology Massachusetts General Hospital Charlestown Massachusetts 02129.
authors.forename: Andre
authors.initials: A
authors.lastname: van der Kouwe
authors.affiliation: 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; Mood and Motor Control Laboratory Massachusetts General Hospital Charlestown Massachusetts 02129.
authors.forename: Anne J
authors.initials: AJ
authors.lastname: Blood
authors.affiliation: 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; Warren Wright Adolescent Center Department of Psychiatry and Behavioral Sciences Northwestern University Feinberg School of Medicine Chicago Illinois 06011; Mood and Motor Control Laboratory Massachusetts General Hospital Charlestown Massachusetts 02129.
authors.forename: Hans C
authors.initials: HC
authors.lastname: Breiter
mesh_terms: D000293:Adolescent; D000328:Adult; D002421:Caudate Nucleus / Q000502:physiology* / Q000503:physiopathology; D002755:Choice Behavior / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D002189:Marijuana Abuse / Q000503:physiopathology*; D009714:Nucleus Accumbens / Q000502:physiology* / Q000503:physiopathology; D010379:Peer Group; D012919:Social Behavior; D055815:Young Adult
keywords: Cannabis; marijuana; nucleus accumbens; peer groups; reward; social influence