title: Dysfunction of dorsolateral prefrontal cortex in antipsychotic-naïve schizophreniform psychosis.
abstract: Reports of abnormal activation of the dorsolateral prefrontal cortex (dlPFC) are common in functional neuroimaging studies of schizophrenia, although very few have examined brain activity in patients close to the onset of illness. In this H(2)(15)O PET study, eight young male patients with first-episode schizophreniform psychosis and age-matched control subjects performed a version of the Stroop task that we have previously shown to engage the middle-frontal gyrus. At the time of testing, patients were antipsychotic-naïve and were scanned within 1 week of initial contact with our clinical program. All patients received a later diagnosis of schizophrenia 6 months after participating in the study. Whole-brain (within-group) and region-of-interest (between-group) analyses were carried out and data underwent spatial reproducibility testing. Compared with healthy subjects, patients showed significantly greater reaction-time (RT) interference but normal RT accuracy on the Stroop task. This pattern correlated with significant under-activation of the posterior left middle-frontal gyri in the patient versus control group. These findings support an emerging model of impaired cognitive control in schizophrenia and suggest that there is significant dysfunction of the dlPFC close to the onset of illness that may coincide with, or be modulated by, the transition-to-illness phase.
authors.affiliation: Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne, Australia. habj@unimelb.edu
authors.forename: Ben J
authors.initials: BJ
authors.lastname: Harrison
authors.forename: Murat
authors.initials: M
authors.lastname: Yücel
authors.forename: Marnie
authors.initials: M
authors.lastname: Shaw
authors.forename: Warrick J
authors.initials: WJ
authors.lastname: Brewer
authors.forename: Pradeep J
authors.initials: PJ
authors.lastname: Nathan
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Strother
authors.forename: James S
authors.initials: JS
authors.lastname: Olver
authors.forename: Gary F
authors.initials: GF
authors.lastname: Egan
authors.forename: Dennis
authors.initials: D
authors.lastname: Velakoulis
authors.forename: Patrick D
authors.initials: PD
authors.lastname: McGorry
authors.forename: Christos
authors.initials: C
authors.lastname: Pantelis
mesh_terms: D000293:Adolescent; D000328:Adult; D001288:Attention / Q000502:physiology*; D001921:Brain / Q000000981:diagnostic imaging / Q000503:physiopathology; D003118:Color Perception / Q000502:physiology*; D003220:Conflict, Psychological; D004193:Discrimination Learning / Q000502:physiology*; D018450:Disease Progression; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008297:Male; D009415:Nerve Net / Q000000981:diagnostic imaging / Q000503:physiopathology; D049268:Positron-Emission Tomography; D017397:Prefrontal Cortex / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D011618:Psychotic Disorders / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D011930:Reaction Time / Q000502:physiology*; D012559:Schizophrenia / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D012660:Semantics; D013223:Statistics as Topic