title: Disrupted gamma-band neural oscillations during coherent motion perception in heavy cannabis users.
abstract: Previous work in animals and humans has shown that exogenous cannabinoids disrupt time-locked, evoked gamma oscillations (30-80 Hz). However, no studies to date have examined the effect of cannabis on non-time-locked, induced gamma oscillations during more complex Gestalt perception. The current study therefore utilized electroencephalography (EEG) to examine gamma oscillations during coherent motion perception in heavy cannabis users and controls. Chronic cannabis users (n = 24; 12 h abstinence before study; positive 11-nor-9-carboxy-delta-9-tetrahydrocannabinol urine levels) and cannabis-naive controls (n = 23) were evaluated. Stimuli consisted of random dot kinetograms (RDKs) that subjects passively viewed during three different conditions: coherent motion, incoherent motion, and static. Time × frequency analysis on EEG data was performed using Fourier-based mean trial power (MTP). Transient event-related potentials (ERPs) to stimulus onset (visual N100 and P200 components) were also evaluated. The results showed that the coherent motion condition produced a robust increase in neural activity in the gamma range (induced power from 40 to 59 Hz) as compared with the incoherent motion and static conditions. As predicted, the cannabis group showed significant reductions in induced gamma power in the coherent condition relative to healthy controls. No differences were observed between the groups in the N100 or P200 components, indicating intact primary sensory processing. Finally, cannabis users showed a trend toward increased scores on the Chapman Perceptual Aberration Scale (PAS) that was positively correlated with total years of active cannabis use. These data suggest that cannabis use may interfere with the generation of induced gamma-band neural oscillations that could in part mediate the perceptual-altering effects of exogenous cannabinoids.
authors.affiliation: Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA.
authors.forename: Patrick D
authors.initials: PD
authors.lastname: Skosnik
authors.affiliation: Department of Cell Biology and Neuroscience, University of California, Riverside, Riverside, CA, USA.
authors.forename: Giri P
authors.initials: GP
authors.lastname: Krishnan
authors.affiliation: Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA.
authors.forename: Deepak C
authors.initials: DC
authors.lastname: D'Souza
authors.affiliation: Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA.
authors.forename: William P
authors.initials: WP
authors.lastname: Hetrick
authors.affiliation: Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA.
authors.forename: Brian F
authors.initials: BF
authors.lastname: O'Donnell
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001931:Brain Mapping; D002186:Cannabinoids; D004569:Electroencephalography; D005260:Female; D005583:Fourier Analysis; D065818:Gamma Rhythm / Q000502:physiology*; D006801:Humans; D016014:Linear Models; D008297:Male; D002189:Marijuana Abuse / Q000150:complications*; D009039:Motion Perception / Q000502:physiology*; D010468:Perceptual Disorders / Q000209:etiology*; D010775:Photic Stimulation; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D002186:Cannabinoids