title: Discrete alterations of brain network structural covariance in individuals at ultra-high risk for psychosis.
abstract: BACKGROUND
  Investigation of aberrant large-scale brain networks offers novel insight into the role these networks play in diverse psychiatric disorders such as schizophrenia. Although studies report altered functional brain connectivity in participants at ultra-high risk (UHR) for psychosis, it is unclear whether these alterations extend to structural brain networks.
  
  
  METHODS
  Whole-brain structural covariance patterns of 133 participants at UHR for psychosis (51 of whom subsequently developed psychosis) and 65 healthy control (HC) subjects were studied. Following data preprocessing (using VBM8 toolbox), the mean signal in seed regions relating to specific networks (visual, auditory, motor, speech, semantic, executive control, salience, and default-mode) were extracted, and voxel-wise analyses of covariance were conducted to compare the association between whole-brain signal and each seed region for UHR and HC individuals. The UHR participants who transitioned to psychosis were compared with the UHR participants who did not.
  
  
  RESULTS
  Significantly reduced structural covariance was observed in the UHR sample compared with the HC sample for the default-mode network, and increased covariance was observed for the motor and executive control networks. When the UHR participants who transitioned to psychosis were compared with the UHR participants who did not, aberrant structural covariance was observed in the salience, executive control, auditory, and motor networks.
  
  
  CONCLUSIONS
  Whole-brain structural covariance analyses revealed subtle changes of connectivity of the default-mode, executive control, salience, motor, and auditory networks in UHR individuals for psychosis. Although we found significant differences, these are small changes and tend to reflect largely intact structural networks.
authors.affiliation: School of Psychology, University of Birmingham, Birmingham, United Kingdom. Electronic address: kxh114@bham.ac.uk.
authors.forename: Kareen
authors.initials: K
authors.lastname: Heinze
authors.affiliation: School of Psychology, University of Birmingham, Birmingham, United Kingdom.
authors.forename: Renate L E P
authors.initials: RL
authors.lastname: Reniers
authors.affiliation: Orygen Youth Health Research Centre, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Barnaby
authors.initials: B
authors.lastname: Nelson
authors.affiliation: Orygen Youth Health Research Centre, University of Melbourne, Melbourne, Victoria, Australia; Institute of Brain, Behavior and Mental Health, University of Manchester, Manchester, United Kingdom.
authors.forename: Alison R
authors.initials: AR
authors.lastname: Yung
authors.affiliation: Telethon Kids Institute, University of Western Australia, Perth, Western Australia.
authors.forename: Ashleigh
authors.initials: A
authors.lastname: Lin
authors.affiliation: Melbourne Neuropsychiatry Centre, Department of Psychiatry, University of Melbourne and Melbourne Health, Carlton South, Victoria, Australia.
authors.forename: Ben J
authors.initials: BJ
authors.lastname: Harrison
authors.affiliation: Melbourne Neuropsychiatry Centre, Department of Psychiatry, University of Melbourne and Melbourne Health, Carlton South, Victoria, Australia.
authors.forename: Christos
authors.initials: C
authors.lastname: Pantelis
authors.affiliation: Melbourne Neuropsychiatry Centre, Department of Psychiatry, University of Melbourne and Melbourne Health, Carlton South, Victoria, Australia.
authors.forename: Dennis
authors.initials: D
authors.lastname: Velakoulis
authors.affiliation: Orygen Youth Health Research Centre, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Patrick D
authors.initials: PD
authors.lastname: McGorry
authors.affiliation: School of Psychology, University of Birmingham, Birmingham, United Kingdom; Melbourne Neuropsychiatry Centre, Department of Psychiatry, University of Melbourne and Melbourne Health, Carlton South, Victoria, Australia.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Wood
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001921:Brain / Q000473:pathology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D011569:Psychiatric Status Rating Scales; D011618:Psychotic Disorders / Q000473:pathology* / Q000503:physiopathology*; D012307:Risk Factors; D055815:Young Adult
keywords: Default-mode network; Network-level; Psychosis; Structural covariance; Transition; Ultra-high risk