title: Abnormal medial prefrontal cortex activity in heavy cannabis users during conscious emotional evaluation.
abstract: BACKGROUND
  Long-term heavy cannabis users (cannabis users) who are not acutely intoxicated have diminished subconscious neural responsiveness to affective stimuli.
  
  
  OBJECTIVE
  This study sought to determine if abnormal processing extends to the conscious evaluation of emotional stimuli.
  
  
  METHODS
  Functional magnetic resonance imaging (fMRI) was used to examine brain activity as cannabis users (N = 16) and non-cannabis-using controls (N = 17) evaluated and categorized standardized International Affective Picture System (IAPS) stimuli. Individual judgments were used to isolate activity during the evaluation of emotional (i.e., emotional evaluation) or neutral (i.e., neutral evaluation) stimuli. Within- and between-group analyses were performed.
  
  
  RESULTS
  Both groups judged the same stimuli as emotional and had activations in visual, midbrain, and middle cingulate cortices during emotional evaluation, relative to neutral. Within-group analyses also revealed amygdalar and inferior frontal gyrus activations in controls, but not cannabis users, and medial prefrontal cortex (mPFC) deactivations in cannabis users, but not controls, during emotional evaluation, relative to neutral. Between-group comparisons found that mPFC activity during positive and negative evaluation was significantly hypoactive in cannabis users, relative to controls.
  
  
  CONCLUSIONS
  Abnormal neural processing of affective content extends to the level of consciousness in cannabis users. The hypoactive mPFC responses observed resembles the attenuated mPFC responses found during increased non-affective cognitive load in prior research. These findings suggest that abnormal mPFC singling in cannabis users during emotional evaluation might be associated with increased non-affective cognitive load.
authors.affiliation: Department of Behavioral Science, University of Kentucky College of Medicine, Medical Behavioral Science Building, Lexington, KY, USA. michael.wesley@uky.edu.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Wesley
authors.affiliation: Department of Behavioral Science, University of Kentucky College of Medicine, Medical Behavioral Science Building, Lexington, KY, USA.
authors.forename: Joshua A
authors.initials: JA
authors.lastname: Lile
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA.
authors.forename: Colleen A
authors.initials: CA
authors.lastname: Hanlon
authors.affiliation: Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, USA.
authors.forename: Linda J
authors.initials: LJ
authors.lastname: Porrino
mesh_terms: D000328:Adult; D000679:Amygdala / Q000503:physiopathology; D001931:Brain Mapping / Q000379:methods; D004644:Emotions / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D002189:Marijuana Abuse / Q000503:physiopathology* / Q000523:psychology; D008385:Marijuana Smoking / Q000503:physiopathology* / Q000523:psychology; D017397:Prefrontal Cortex / Q000503:physiopathology*; D055815:Young Adult
keywords: Cannabis; Emotion; Human; Medial PFC; fMRI