Psychopharmacology

, Volume 183, Issue 1, pp 92–102

Effects of ketamine on prefrontal and striatal regions in an overt verbal fluency task: a functional magnetic resonance imaging study

  • Cynthia H. Y. Fu
  • Kathryn M. Abel
  • Matthew P. G. Allin
  • David Gasston
  • Sergi G. Costafreda
  • John Suckling
  • Steve C. R. Williams
  • Philip K. McGuire
Original Investigation

DOI: 10.1007/s00213-005-0154-9

Cite this article as:
Fu, C.H.Y., Abel, K.M., Allin, M.P.G. et al. Psychopharmacology (2005) 183: 92. doi:10.1007/s00213-005-0154-9

Abstract

Rationale

Glutamatergic dysfunction at N-methyl-d-aspartate (NMDA) receptors has been proposed as a neurochemical model for schizophrenia. A key feature of this disorder is impairments in cognitive function.

Objective

The present study sought to investigate the effects of ketamine, an NMDA antagonist, on the performance and neural correlates of verbal fluency, a task that engages executive function.

Methods

Ten healthy dextral male volunteers received intravenous placebo normal saline or ketamine (bolus of 0.23 mg/kg and infusion of 0.65 mg/kg), administered in a double-blind, randomized order, during two functional magnetic resonance imaging sessions. During scanning, subjects performed a verbal fluency task. Two levels of cognitive load were examined in the task, and overt responses were acquired in order to measure subject performance on-line.

Results

Ketamine induced symptoms in the healthy individuals comparable to an acute psychotic state. Although ketamine did not significantly impair task performance relative to placebo, an interaction of task demand with ketamine was observed in the anterior cingulate, prefrontal, and striatal regions.

Conclusions

The behavioural and functional effects of ketamine during verbal fluency in healthy individuals were comparable to those evident in patients with schizophrenia. The findings support a role for glutamatergic dysfunction in the pathophysiology of schizophrenia.

Keywords

Ketamine N-methyl-d-aspartate NMDA Schizophrenia Verbal fluency Executive function Functional magnetic resonance imaging fMRI 

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • Cynthia H. Y. Fu
    • 1
  • Kathryn M. Abel
    • 2
  • Matthew P. G. Allin
    • 1
  • David Gasston
    • 1
  • Sergi G. Costafreda
    • 1
  • John Suckling
    • 3
  • Steve C. R. Williams
    • 1
  • Philip K. McGuire
    • 1
  1. 1.Institute of PsychiatryKing's College LondonLondonUK
  2. 2.Department of Psychiatry and Behavioural SciencesManchester UniversityManchesterUK
  3. 3.Brain Mapping Unit, Department of Psychiatry, Addenbrooke's HospitalUniversity of CambridgeCambridgeUK

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