title: Reduced brain cortical folding in schizophrenia revealed in two independent samples.
abstract: The cerebral cortex is highly convoluted, and principal folding patterns are determined early in life. Degree of cortical folding in adult life may index aberrations in brain development. Results from previous studies of cortical folding in schizophrenia are inconsistent. Here we investigated cortical folding patterns in the hitherto largest sample of patients with schizophrenia drawn from two independent cohorts. Magnetic resonance imaging scans were acquired from 207 patients and 206 healthy subjects recruited to two separate research projects in Sweden and Norway. Local gyrification index (lGI) was estimated continuously across the cortex using automated methods. Group differences in lGI were analyzed using general linear models. Patients had lower lGI in three large clusters of the cortex with peak differences found in the left precentral gyrus, right middle temporal gyrus, and right precuneus. Similar, although not completely overlapping results were found when the two cohorts were analyzed separately. There were no significant interaction effects between age and diagnosis and gender and diagnosis. The finding of reduced degree of folding in large regions of the cerebral cortex across two independent samples indicates that reduced gyrification is an inherent feature of the brain pathology in schizophrenia.
authors.affiliation: Department of Psychiatric Research, Diakonhjemmet Hospital, Oslo, Norway; Division of Mental Health, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Ragnar
authors.initials: R
authors.lastname: Nesvåg
authors.affiliation: Office Médico-Pédagogique, Department of Psychiatry, Geneva Faculty of Medicine, Geneva, Switzerland; Stanford Cognitive and Systems Neuroscience Laboratory, Stanford University School of Medicine, CA, USA.
authors.forename: Marie
authors.initials: M
authors.lastname: Schaer
authors.affiliation: Department of Psychiatric Research, Diakonhjemmet Hospital, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: Unn K
authors.initials: UK
authors.lastname: Haukvik
authors.affiliation: K. G. Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo & Oslo University Hospital, Oslo, Norway; Department of Psychology, University of Oslo, Oslo, Norway.
authors.forename: Lars T
authors.initials: LT
authors.lastname: Westlye
authors.affiliation: Department of Psychiatric Research, Diakonhjemmet Hospital, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: Lars M
authors.initials: LM
authors.lastname: Rimol
authors.affiliation: Department of Psychiatric Research, Diakonhjemmet Hospital, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: Elisabeth H
authors.initials: EH
authors.lastname: Lange
authors.affiliation: Department of Psychiatry, Diakonhjemmet Hospital, Oslo, Norway.
authors.forename: Cecilie B
authors.initials: CB
authors.lastname: Hartberg
authors.affiliation: Office Médico-Pédagogique, Department of Psychiatry, Geneva Faculty of Medicine, Geneva, Switzerland.
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Ottet
authors.affiliation: Institute of Clinical Medicine, University of Oslo, Oslo, Norway; K. G. Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo & Oslo University Hospital, Oslo, Norway.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Melle
authors.affiliation: Institute of Clinical Medicine, University of Oslo, Oslo, Norway; K. G. Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo & Oslo University Hospital, Oslo, Norway.
authors.forename: Ole A
authors.initials: OA
authors.lastname: Andreassen
authors.affiliation: Department of Clinical Neuroscience, HUBIN Project, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Erik G
authors.initials: EG
authors.lastname: Jönsson
authors.affiliation: Department of Psychiatric Research, Diakonhjemmet Hospital, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway; K. G. Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo & Oslo University Hospital, Oslo, Norway; Department of Clinical Neuroscience, HUBIN Project, Karolinska Institutet, Stockholm, Sweden. Electronic address: Ingrid.agartz@medisin.uio.no.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Agartz
authors.affiliation: Office Médico-Pédagogique, Department of Psychiatry, Geneva Faculty of Medicine, Geneva, Switzerland.
authors.forename: Stephan
authors.initials: S
authors.lastname: Eliez
mesh_terms: D000328:Adult; D000367:Age Factors; D002540:Cerebral Cortex / Q000473:pathology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007391:International Cooperation; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012559:Schizophrenia / Q000473:pathology*
keywords: Cortical thickness; FreeSurfer; Local gyrification index; Magnetic resonance imaging