Functional imaging of implicit marijuana associations during performance on an Implicit Association Test (IAT)

Susan L. AMES, Jerry L. GRENARD, Alan W. STACY, Lin XIAO, Qinghua HE, Wai Ho Savio WONG, Gui XUE, Reinout W. WIERS, Antoine BECHARA

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This research evaluated the neural correlates of implicit associative memory processes (habit-based processes) through the imaging (fMRI) of a marijuana Implicit Association Test. Drug-related associative memory effects have been shown to consistently predict level of drug use. To observe differences in neural activity of associative memory effects, this study compared 13 heavy marijuana users and 15 non-using controls, ranging in age from 18 to 25, during performance of marijuana Implicit Association Test (IAT). Group by condition interactions in the putamen, caudate, and right inferior frontal gyrus were observed. Relative to non-users, marijuana users showed greater bilateral activity in the dorsal striatum (caudate and putamen) during compatible trials focused on perceived positive outcomes of use. Alternatively, relative to the marijuana-using group, the non-users showed greater activity in the right inferior frontal gyrus during incompatible trials, which require more effortful processing of information. Further, relative to fixation, heavy users showed bilateral activity in the caudate and putamen, hippocampus and some frontal regions during compatible trials and no significant activity during incompatible trials. The non-using group showed greater activity in frontal regions during incompatible trials relative to fixation and no significant activity during compatible trials. These findings are consistent with a dual process framework of appetitive behaviors proposing that (1) implicit associations underlying habit are mediated through neural circuitry dependent on the striatum, and (2) deliberative/controlled behaviors are mediated through circuitry more dependent on the prefrontal cortex. Copyright © 2013 Elsevier B.V.
Original languageEnglish
Pages (from-to)494-502
JournalBehavioural Brain Research
Issue number1
Early online dateSep 2013
Publication statusPublished - Nov 2013


Prefrontal Cortex
Appetitive Behavior
Automatic Data Processing
Pharmaceutical Preparations
Magnetic Resonance Imaging


Ames, S. L., Grenard, J. L., Stacy, A. W., Xiao, L., He, Q. H., Wong, S. W., Xue, G., Wiers, R. W., & Bechara, A. (2013). Functional imaging of implicit marijuana associations during performance on an Implicit Association Test (IAT). Behavioural Brain Research, 256(1), 494–502.


  • fMRI
  • Marijuana IAT
  • Habit
  • Associative processes
  • Memory associations
  • Implicit cognition