title: A greater involvement of posterior brain areas in interhemispheric transfer in autism: fMRI, DWI and behavioral evidences.
abstract: A small corpus callosum (CC) is one of the most replicated neurobiological findings in autism spectrum (AS). However, its effect on interhemispheric (IH) communication is unknown. We combined structural (CC area and DWI), functional (task-related fMRI activation and connectivity analyses) as well as behavioral (Poffenberger and Purdue tasks) measures to investigate IH integration in adult AS individuals of typical intelligence. Despite similar behavioral IH transfer time and performances in bimanual tasks, the CC sub-regions connecting frontal and parietal cortical areas were smaller in AS than in non-AS individuals, while those connecting visual regions were similar. The activation of visual areas was lower in AS than in non-AS individuals during the presentation of visual stimuli. Behavioral IH performances were related to the properties of CC subregions connecting motor areas in non-AS individuals, but to the properties of posterior CC regions in AS individuals. Furthermore, there was greater functional connectivity between visual areas in the AS than in the non-AS group. Levels of connectivity were also stronger in visual than in motor regions in the autistic subjects, while the opposite was true for the non-autistic group. Thus, visual IH transfer plays an important role in visuo-motor tasks in AS individuals. These findings extend the well established enhanced role of perception in autistic cognition to visuo-motor IH information transfer.
authors.affiliation: Centre d'Excellence en Troubles Envahissants du Développement de l'Université de Montréal (CETEDUM), Montréal, QC, Canada ; Centre de recherche de l'Institut universitaire de santé mentale de Montréal, Montréal, QC, Canada ; Département de Psychiatrie, Université de Montréal, Montréal, QC, Canada.
authors.forename: Elise B
authors.initials: EB
authors.lastname: Barbeau
authors.affiliation: Montreal Neurological Institute, McGill University, Montréal, QC, Canada.
authors.forename: John D
authors.initials: JD
authors.lastname: Lewis
authors.affiliation: Département de Psychologie de l'Université de Montréal & Unité de Neuroimagerie Fonctionnelle (UNF), Montréal, QC, Canada.
authors.forename: Julien
authors.initials: J
authors.lastname: Doyon
authors.affiliation: Laboratoire d'Imagerie Fonctionnelle - U678, Faculté de Médecine Pierre et Marie Curie - Pitié Salpétrière, Paris, France.
authors.forename: Habib
authors.initials: H
authors.lastname: Benali
authors.affiliation: Neural Systems Group, Massachusetts General Hospital, Psychiatry, Charlestown, MA, USA.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Zeffiro
authors.affiliation: Centre d'Excellence en Troubles Envahissants du Développement de l'Université de Montréal (CETEDUM), Montréal, QC, Canada ; Centre de recherche de l'Institut universitaire de santé mentale de Montréal, Montréal, QC, Canada ; Département de Psychiatrie, Université de Montréal, Montréal, QC, Canada.
authors.forename: Laurent
authors.initials: L
authors.lastname: Mottron
mesh_terms: D000293:Adolescent; D000328:Adult; D000067877:Autism Spectrum Disorder / Q000473:pathology / Q000503:physiopathology*; D002540:Cerebral Cortex / Q000503:physiopathology*; D003337:Corpus Callosum / Q000473:pathology / Q000503:physiopathology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011597:Psychomotor Performance / Q000502:physiology*; D055815:Young Adult
keywords: Autism; Corpus callosum; Cortical reorganization; Poffenberger; Purdue; Visuo-motor integration