title: The effects of ketamine on the mismatch negativity (MMN) in humans - A meta-analysis.
abstract: OBJECTIVE
  To investigate whether effects of the glutamatergic N-methyl-d-aspartate (NMDA) receptor antagonist ketamine on the mismatch negativity (MMN) vary between duration and frequency deviants, as suggested by clinical studies on schizophrenia patients.
  
  
  METHODS
  Our meta-analysis included previous studies that used ketamine in order to induce psychotic experiences in healthy participants and that recorded the MMN either by electroencephalography or magnetoencephalography.
  
  
  RESULTS
  The analysis revealed systematic MMN amplitude decreases and, with a lower effect size, latency increases after ketamine administration. However, the observed amplitude and latency effects did not vary between duration and frequency deviants.
  
  
  CONCLUSIONS
  Across studies, there is no evidence that ketamine effects on the MMN are larger for duration than frequency deviants.
  
  
  CONCLUSIONS
  Our findings tentatively suggest that, in addition to an NMDA receptor hypofunction, other factors might contribute to the sometimes observed pattern of impaired MMN responses to duration deviants, but unimpaired MMN responses to frequency deviants in schizophrenia.
authors.affiliation: Department of Psychology, Experimental Neuropsychology Unit, Saarland University, D-66041 Saarbrücken, Germany; Department of Forensic Psychiatry, University Psychiatric Clinics, Wilhelm Klein-Str. 27, CH-4012 Basel, Switzerland. Electronic address: timm.rosburg@upkbs.ch.
authors.forename: Timm
authors.initials: T
authors.lastname: Rosburg
authors.affiliation: Department of Neurosurgery, University Hospital Essen, University of Essen-Duisburg, D-45147 Essen, Germany.
authors.forename: Ilonka
authors.initials: I
authors.lastname: Kreitschmann-Andermahr
mesh_terms: D000818:Animals; D001307:Auditory Perception / Q000187:drug effects / Q000502:physiology; D004569:Electroencephalography / Q000187:drug effects* / Q000379:methods; D005072:Evoked Potentials, Auditory / Q000187:drug effects / Q000502:physiology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D006801:Humans; D007649:Ketamine / Q000494:pharmacology*; D015225:Magnetoencephalography / Q000187:drug effects* / Q000379:methods; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors*
chemical_list: D018691:Excitatory Amino Acid Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D007649:Ketamine
keywords: Animal model; Auditory discrimination; Event-related potentials; Glutamate; Meta-analysis; Mismatch negativity (MMN); Schizophrenia