title: Is there a relation between novelty seeking, striatal dopamine release and frontal cortical thickness?
abstract: BACKGROUND
  Novelty-seeking (NS) and impulsive personality traits have been proposed to reflect an interplay between fronto-cortical and limbic systems, including the limbic striatum (LS). Although neuroimaging studies have provided some evidence for this, most are comprised of small samples and many report surprisingly large effects given the challenges of trying to relate a snapshot of brain function or structure to an entity as complex as personality. The current work tested a priori hypotheses about associations between striatal dopamine (DA) release, cortical thickness (CT), and NS in a large sample of healthy adults.
  
  
  METHODS
  Fifty-two healthy adults (45M/7F; age: 23.8±4.93) underwent two positron emission tomography scans with [11C]raclopride (specific for striatal DA D2/3 receptors) with or without amphetamine (0.3 mg/kg, p.o.). Structural magnetic resonance image scans were acquired, as were Tridimensional Personality Questionnaire data. Amphetamine-induced changes in [11C]raclopride binding potential values (ΔBPND) were examined in the limbic, sensorimotor (SMS) and associative (AST) striatum. CT measures, adjusted for whole brain volume, were extracted from the dorsolateral sensorimotor and ventromedial/limbic cortices.
  
  
  RESULTS
  BPND values were lower in the amphetamine vs. no-drug sessions, with the largest effect in the LS. When comparing low vs. high LS ΔBPND groups (median split), higher NS2 (impulsiveness) scores were found in the high ΔBPND group. Partial correlations (age and gender as covariates) yielded a negative relation between ASTS ΔBPND and sensorimotor CT; trends for inverse associations existed between ΔBPND values in other striatal regions and frontal CT. In other words, the greater the amphetamine-induced striatal DA response, the thinner the frontal cortex.
  
  
  CONCLUSIONS
  These data expand upon previously reported associations between striatal DA release in the LS and both NS related impulsiveness and CT in the largest sample reported to date. The findings add to the plausibility of these associations while suggesting that the effects are likely weaker than has been previously proposed.
authors.affiliation: Department of Psychiatry, McGill University, Montreal, Quebec, Canada.|Institue of Mental Health Research, Ottawa, Ontario, Canada.
authors.forename: Natalia
authors.identifier: http://orcid.org/0000-0001-5643-8210
authors.initials: N
authors.lastname: Jaworska
authors.affiliation: Department of Psychiatry, McGill University, Montreal, Quebec, Canada.
authors.forename: Sylvia M
authors.initials: SM
authors.lastname: Cox
authors.affiliation: Le Centre Hospitalier Universitaire (CHU) Sainte-Justine, Montreal, Quebec, Canada.
authors.forename: Kevin F
authors.initials: KF
authors.lastname: Casey
authors.affiliation: Centre for Addiction & Mental Health (CAMH), Toronto, Ontario, Canada.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Boileau
authors.affiliation: University of British Columbia, Division of Neurology, Vancouver, British Columbia, Canada.
authors.forename: Mariya
authors.initials: M
authors.lastname: Cherkasova
authors.affiliation: Montreal Neurological Institute (MNI), McGill University, Montreal, Quebec, Canada.
authors.forename: Kevin
authors.initials: K
authors.lastname: Larcher
authors.affiliation: Montreal Neurological Institute (MNI), McGill University, Montreal, Quebec, Canada.
authors.forename: Alain
authors.initials: A
authors.lastname: Dagher
authors.affiliation: Department of Psychiatry, McGill University, Montreal, Quebec, Canada.
authors.forename: Chawki
authors.initials: C
authors.lastname: Benkelfat
authors.affiliation: Department of Psychiatry, McGill University, Montreal, Quebec, Canada.
authors.forename: Marco
authors.initials: M
authors.lastname: Leyton
mesh_terms: D000328:Adult; D003342:Corpus Striatum / Q000502:physiology*; D004298:Dopamine / Q000378:metabolism*; D005106:Exploratory Behavior; D005260:Female; D005625:Frontal Lobe / Q000033:anatomy & histology / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009929:Organ Size; D049268:Positron-Emission Tomography; D055815:Young Adult
chemical_list: D004298:Dopamine