title: Perceptual organization in ketamine users: preliminary evidence of deficits on night of drug use but not 3 days later.
abstract: N-methyl-D-aspartate (NMDA)-receptor antagonists such as ketamine can induce transient schizophrenia-like symptoms and cognitive dysfunctions in healthy volunteers similar to those observed in patients with schizophrenia. Perceptual organization deficits have been documented in schizophrenia and are thought to be related to some symptoms associated with the illness. The current study was designed to determine whether people who repeatedly self-administer ketamine would also show deficits in perceptual organization. Using a psychophysically well-controlled measure of contour integration, we compared a group of recreational users (n = 16) to a group of poly-drug using controls (n = 16). Contour integration performance was measured on the night of drug use and 3 days later when drug free. The results showed that on the night of drug use, ketamine produced a dysfunction in contour integration however, this was not present 3 days later when drug free. Levels of dissociation were also higher in ketamine users only on the night of drug use. These preliminary data provide some support for the role of NMDA-receptor hypofunctioning in dysfunctional coordination of cognitive activity.
authors.affiliation: Max Planck Institute for Brain Research, Frankfurt, Germany.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Uhlhaas
authors.forename: Isobel
authors.initials: I
authors.lastname: Millard
authors.forename: Leslie
authors.initials: L
authors.lastname: Muetzelfeldt
authors.forename: H Valerie
authors.initials: HV
authors.lastname: Curran
authors.forename: Celia J A
authors.initials: CJ
authors.lastname: Morgan
mesh_terms: D000293:Adolescent; D000328:Adult; D000647:Amnesia / Q000139:chemically induced / Q000523:psychology; D003702:Delusions / Q000139:chemically induced / Q000523:psychology; D003861:Depersonalization / Q000139:chemically induced / Q000523:psychology; D004213:Dissociative Disorders / Q000139:chemically induced / Q000523:psychology; D018691:Excitatory Amino Acid Antagonists; D005260:Female; D006801:Humans; D007649:Ketamine; D008297:Male; D009483:Neuropsychological Tests; D010465:Perception / Q000187:drug effects*; D011597:Psychomotor Performance / Q000187:drug effects; D019966:Substance-Related Disorders / Q000523:psychology*; D014796:Visual Perception / Q000187:drug effects
chemical_list: D018691:Excitatory Amino Acid Antagonists; D007649:Ketamine