title: Abnormal relationship between medial temporal lobe and subcortical dopamine function in people with an ultra high risk for psychosis.
abstract: BACKGROUND
  Neuroimaging studies in humans have implicated both dysfunction of the medial temporal lobe (MTL) and the dopamine system in psychosis, but the relationship between them is unclear. We addressed this issue by measuring MTL activation and striatal dopaminergic function in individuals with an At Risk Mental State (ARMS) for psychosis, using functional magnetic resonance imaging (fMRI) and positron emission tomography (PET), respectively.
  
  
  METHODS
  Thirty-four subjects (20 ARMS and 14 Controls), matched for age, gender, digit span performance, and premorbid IQ, were scanned using fMRI, while performing a verbal encoding and recognition task, and using 18F-DOPA PET. All participants were naïve to antipsychotic medication.
  
  
  RESULTS
  ARMS subjects showed reduced MTL activation when encoding words and made more false alarm responses for Novel words than controls. The relationship between striatal dopamine function and MTL activation during both verbal encoding and verbal recognition was significantly different in ARMS subjects compared with controls.
  
  
  CONCLUSIONS
  An altered relationship between MTL function and dopamine storage/synthesis capacity exists in the ARMS and may be related to psychosis vulnerability.
authors.affiliation: Department of Psychosis Studies, Institute of Psychiatry, King's College London, London, UK. p.allen@kcl.ac.uk
authors.forename: Paul
authors.initials: P
authors.lastname: Allen
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Chaddock
authors.forename: Oliver D
authors.initials: OD
authors.lastname: Howes
authors.forename: Alice
authors.initials: A
authors.lastname: Egerton
authors.forename: Marc L
authors.initials: ML
authors.lastname: Seal
authors.forename: Paolo
authors.initials: P
authors.lastname: Fusar-Poli
authors.forename: Isabel
authors.initials: I
authors.lastname: Valli
authors.forename: Fern
authors.initials: F
authors.lastname: Day
authors.forename: Philip K
authors.initials: PK
authors.lastname: McGuire
mesh_terms: D000328:Adult; D001931:Brain Mapping; D003342:Corpus Striatum / Q000503:physiopathology*; D004292:Dominance, Cerebral / Q000502:physiology; D004298:Dopamine / Q000502:physiology*; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008032:Limbic System / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D009415:Nerve Net / Q000503:physiopathology; D010100:Oxygen / Q000097:blood; D049268:Positron-Emission Tomography; D011569:Psychiatric Status Rating Scales; D021641:Recognition, Psychology / Q000502:physiology; D012307:Risk Factors; D012559:Schizophrenia / Q000175:diagnosis / Q000235:genetics* / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D013702:Temporal Lobe / Q000503:physiopathology*; D014706:Verbal Learning / Q000502:physiology; D014888:Wechsler Scales; D055815:Young Adult
chemical_list: D010100:Oxygen; D004298:Dopamine