title: Multimodal analyses identify linked functional and white matter abnormalities within the working memory network in schizophrenia.
abstract: BACKGROUND
  Dysconnectivity between brain regions is thought to underlie the cognitive abnormalities that characterise schizophrenia (SZ). Consistent with this notion functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) studies in SZ have reliably provided evidence of abnormalities in functional integration and in white matter connectivity. Yet little is known about how alterations at the functional level related to abnormalities in anatomical connectivity.
  
  
  METHODS
  We obtained fMRI data during the 2-back working memory task from 25 patients with SZ and 19 healthy controls matched for age, sex and IQ. DTI data were also acquired in the same session. In addition to conventional unimodal analyses we extracted "features" [contrast maps for fMRI and fractional anisotropy (FA) for DTI] that were subjected to joint independent component analysis (JICA) in order to examine interactions between fMRI and DTI data sources.
  
  
  RESULTS
  Conventional unimodal analyses revealed both functional and structural deficits in patients with SZ. The JICA identified regions of joint, multimodal brain sources that differed in patients and controls. The fMRI source implicated regions within the anterior cingulate and ventrolateral prefrontal cortex and in the cuneus where patients showed relative hypoactivation and within the frontopolar cortex where patients showed relative hyperactivation. The DTI source localised reduced FA in patients in the splenium and posterior cingulum.
  
  
  CONCLUSIONS
  This study promotes our understanding of structure-function relationships in SZ by characterising linked functional and white matter changes that contribute to working memory dysfunction in this disorder.
authors.affiliation: Section of Neurobiology of Psychosis, Dept. of Psychosis Studies, Institute of Psychiatry, King's College London, UK.
authors.forename: Gisela
authors.initials: G
authors.lastname: Sugranyes
authors.forename: Marinos
authors.initials: M
authors.lastname: Kyriakopoulos
authors.forename: Danai
authors.initials: D
authors.lastname: Dima
authors.forename: Jonathan
authors.initials: J
authors.lastname: O'Muircheartaigh
authors.forename: Richard
authors.initials: R
authors.lastname: Corrigall
authors.forename: Gabrielle
authors.initials: G
authors.lastname: Pendelbury
authors.forename: Daniel
authors.initials: D
authors.lastname: Hayes
authors.forename: Vince D
authors.initials: VD
authors.lastname: Calhoun
authors.forename: Sophia
authors.initials: S
authors.lastname: Frangou
mesh_terms: D000293:Adolescent; D016880:Anisotropy; D001931:Brain Mapping; D016022:Case-Control Studies; D003337:Corpus Callosum / Q000473:pathology / Q000503:physiopathology*; D056324:Diffusion Tensor Imaging; D005260:Female; D059907:Functional Neuroimaging; D006179:Gyrus Cinguli / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D009434:Neural Pathways; D017397:Prefrontal Cortex / Q000473:pathology / Q000503:physiopathology*; D012559:Schizophrenia / Q000473:pathology / Q000503:physiopathology*