title: Mismatch negativity predicts psychotic experiences induced by NMDA receptor antagonist in healthy volunteers.
abstract: BACKGROUND
  Previous studies indicate that mismatch negativity (MMN)-a preattentive auditory event-related potential (ERP)-depends on NMDA receptor (NMDAR) functioning. To explore if the strength of MMN generation reflects the functional condition of the NMDAR system in healthy volunteers, we analyzed correlations between MMN recorded before drug administration and subsequent responses to the NMDAR antagonist ketamine or the 5-HT2a agonist psilocybin.
  
  
  METHODS
  In two separate studies, MMN was recorded to both frequency and duration deviants prior to administration of ketamine or psilocybin. Behavioral and subjective effects of ketamine and psilocybin were assessed with the Brief Psychiatric Rating Scale and the OAV Scale-a rating scale developed to measure altered states of consciousness. Correlations between ERP amplitudes (MMN, N1, and P2) and drug-induced effects were calculated in each study group and compared between them.
  
  
  RESULTS
  Smaller MMN to both pitch and duration deviants was significantly correlated to stronger effects during ketamine, but not psilocybin administration. No significant correlations were observed for N1 and P2.
  
  
  CONCLUSIONS
  Smaller MMN indicates a NMDAR system that is more vulnerable to disruption by the NMDAR antagonist ketamine. MMN generation appears to index the functional state of NMDAR-mediated neurotransmission even in subjects who do not demonstrate any psychopathology.
authors.affiliation: Psychiatric University Hospital Zurich, Department of Psychiatric Research, Zurich, Switzerland.
authors.forename: Daniel
authors.initials: D
authors.lastname: Umbricht
authors.forename: Rene
authors.initials: R
authors.lastname: Koller
authors.forename: Franz X
authors.initials: FX
authors.lastname: Vollenweider
authors.forename: Liselotte
authors.initials: L
authors.lastname: Schmid
mesh_terms: D000284:Administration, Oral; D000328:Adult; D002540:Cerebral Cortex / Q000187:drug effects / Q000503:physiopathology; D003265:Contingent Negative Variation / Q000187:drug effects* / Q000502:physiology; D004569:Electroencephalography / Q000187:drug effects; D005072:Evoked Potentials, Auditory / Q000187:drug effects* / Q000502:physiology; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D007649:Ketamine / Q000494:pharmacology*; D008297:Male; D011562:Psilocybin / Q000494:pharmacology; D011569:Psychiatric Status Rating Scales; D011605:Psychoses, Substance-Induced / Q000503:physiopathology*; D044402:Receptor, Serotonin, 5-HT2A; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors* / Q000502:physiology; D011985:Receptors, Serotonin / Q000187:drug effects / Q000502:physiology
chemical_list: D044402:Receptor, Serotonin, 5-HT2A; D016194:Receptors, N-Methyl-D-Aspartate; D011985:Receptors, Serotonin; D011562:Psilocybin; D007649:Ketamine