title: Intrinsic gray-matter connectivity of the brain in adults with autism spectrum disorder.
abstract: Autism spectrum disorders (ASD) are a group of neurodevelopmental conditions that are accompanied by atypical brain connectivity. So far, in vivo evidence for atypical structural brain connectivity in ASD has mainly been based on neuroimaging studies of cortical white matter. However, genetic studies suggest that abnormal connectivity in ASD may also affect neural connections within the cortical gray matter. Such intrinsic gray-matter connections are inherently more difficult to describe in vivo but may be inferred from a variety of surface-based geometric features that can be measured using magnetic resonance imaging. Here, we present a neuroimaging study that examines the intrinsic cortico-cortical connectivity of the brain in ASD using measures of "cortical separation distances" to assess the global and local intrinsic "wiring costs" of the cortex (i.e., estimated length of horizontal connections required to wire the cortex within the cortical sheet). In a sample of 68 adults with ASD and matched controls, we observed significantly reduced intrinsic wiring costs of cortex in ASD, both globally and locally. Differences in global and local wiring cost were predominantly observed in fronto-temporal regions and also significantly predicted the severity of social and repetitive symptoms (respectively). Our study confirms that atypical cortico-cortical "connectivity" in ASD is not restricted to the development of white-matter connections but may also affect the intrinsic gray-matter architecture (and connectivity) within the cortical sheet. Thus, the atypical connectivity of the brain in ASD is complex, affecting both gray and white matter, and forms part of the core neural substrates underlying autistic symptoms.
authors.affiliation: Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, King's College London, London SE5 8AF, United Kingdom. christine.ecker@kcl.ac.uk
authors.forename: Christine
authors.initials: C
authors.lastname: Ecker
authors.forename: Lisa
authors.initials: L
authors.lastname: Ronan
authors.forename: Yue
authors.initials: Y
authors.lastname: Feng
authors.forename: Eileen
authors.initials: E
authors.lastname: Daly
authors.forename: Clodagh
authors.initials: C
authors.lastname: Murphy
authors.forename: Cedric E
authors.initials: CE
authors.lastname: Ginestet
authors.forename: Michael
authors.initials: M
authors.lastname: Brammer
authors.forename: Paul C
authors.initials: PC
authors.lastname: Fletcher
authors.forename: Edward T
authors.initials: ET
authors.lastname: Bullmore
authors.forename: John
authors.initials: J
authors.lastname: Suckling
authors.forename: Simon
authors.initials: S
authors.lastname: Baron-Cohen
authors.forename: Steve
authors.initials: S
authors.lastname: Williams
authors.forename: Eva
authors.initials: E
authors.lastname: Loth
authors.forename: Declan G M
authors.initials: DG
authors.lastname: Murphy
mesh_terms: D000328:Adult; D001321:Autistic Disorder / Q000473:pathology* / Q000503:physiopathology*; D001921:Brain / Q000473:pathology* / Q000503:physiopathology*; D001931:Brain Mapping / Q000379:methods; D002540:Cerebral Cortex / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009415:Nerve Net / Q000473:pathology / Q000503:physiopathology; D055815:Young Adult
keywords: brain structure; gyrification; morphometry