title: Functional connectivity in brain networks underlying cognitive control in chronic cannabis users.
abstract: The long-term effect of regular cannabis use on brain function underlying cognitive control remains equivocal. Cognitive control abilities are thought to have a major role in everyday functioning, and their dysfunction has been implicated in the maintenance of maladaptive drug-taking patterns. In this study, the Multi-Source Interference Task was employed alongside functional magnetic resonance imaging and psychophysiological interaction methods to investigate functional interactions between brain regions underlying cognitive control. Current cannabis users with a history of greater than 10 years of daily or near-daily cannabis smoking (n=21) were compared with age, gender, and IQ-matched non-using controls (n=21). No differences in behavioral performance or magnitude of task-related brain activations were evident between the groups. However, greater connectivity between the prefrontal cortex and the occipitoparietal cortex was evident in cannabis users, as compared with controls, as cognitive control demands increased. The magnitude of this connectivity was positively associated with age of onset and lifetime exposure to cannabis. These findings suggest that brain regions responsible for coordinating behavioral control have an increased influence on the direction and switching of attention in cannabis users, and that these changes may have a compensatory role in mitigating cannabis-related impairments in cognitive control or perceptual processes.
authors.affiliation: Department of Psychiatry, Melbourne Neuropsychiatry Centre, University of Melbourne and Melbourne Health, Melbourne, VIC, Australia. hardingi@unimelb.edu.au
authors.forename: Ian H
authors.initials: IH
authors.lastname: Harding
authors.forename: Nadia
authors.initials: N
authors.lastname: Solowij
authors.forename: Ben J
authors.initials: BJ
authors.lastname: Harrison
authors.forename: Michael
authors.initials: M
authors.lastname: Takagi
authors.forename: Valentina
authors.initials: V
authors.lastname: Lorenzetti
authors.forename: Dan I
authors.initials: DI
authors.lastname: Lubman
authors.forename: Marc L
authors.initials: ML
authors.lastname: Seal
authors.forename: Christos
authors.initials: C
authors.lastname: Pantelis
authors.forename: Murat
authors.initials: M
authors.lastname: Yücel
mesh_terms: D000328:Adult; D017668:Age of Onset; D016022:Case-Control Studies; D003071:Cognition / Q000502:physiology*; D005260:Female; D059907:Functional Neuroimaging / Q000379:methods / Q000523:psychology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000523:psychology; D008297:Male; D002189:Marijuana Abuse / Q000503:physiopathology* / Q000523:psychology*; D009434:Neural Pathways / Q000503:physiopathology; D009778:Occipital Lobe / Q000503:physiopathology*; D010296:Parietal Lobe / Q000503:physiopathology*; D017397:Prefrontal Cortex / Q000503:physiopathology*; D011597:Psychomotor Performance / Q000187:drug effects / Q000502:physiology; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology