title: Autism as a neural systems disorder: a theory of frontal-posterior underconnectivity.
abstract: The underconnectivity theory of autism attributes the disorder to lower anatomical and functional systems connectivity between frontal and more posterior cortical processing. Here we review evidence for the theory and present a computational model of an executive functioning task (Tower of London) implementing the assumptions of underconnectivity. We make two modifications to a previous computational account of performance and brain activity in typical individuals in the Tower of London task (Newman et al., 2003): (1) the communication bandwidth between frontal and parietal areas was decreased and (2) the posterior centers were endowed with more executive capability (i.e., more autonomy, an adaptation is proposed to arise in response to the lowered frontal-posterior bandwidth). The autism model succeeds in matching the lower frontal-posterior functional connectivity (lower synchronization of activation) seen in fMRI data, as well as providing insight into behavioral response time results. The theory provides a unified account of how a neural dysfunction can produce a neural systems disorder and a psychological disorder with the widespread and diverse symptoms of autism.
authors.affiliation: Center for Cognitive Brain Imaging, Department of Psychology, Carnegie Mellon University, Pittsburgh, PA 15213, USA. just@cmu.edu
authors.forename: Marcel Adam
authors.initials: MA
authors.lastname: Just
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Keller
authors.forename: Vicente L
authors.initials: VL
authors.lastname: Malave
authors.forename: Rajesh K
authors.initials: RK
authors.lastname: Kana
authors.forename: Sashank
authors.initials: S
authors.lastname: Varma
mesh_terms: D001321:Autistic Disorder / Q000473:pathology* / Q000503:physiopathology; D001519:Behavior / Q000502:physiology; D001921:Brain / Q000473:pathology* / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000502:physiology; D003071:Cognition / Q000502:physiology; D003198:Computer Simulation; D005625:Frontal Lobe / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008606:Mental Processes / Q000502:physiology; D008959:Models, Neurological; D009434:Neural Pathways / Q000473:pathology / Q000503:physiopathology; D059906:Neuroimaging; D009483:Neuropsychological Tests; D010296:Parietal Lobe / Q000473:pathology* / Q000503:physiopathology; D010465:Perception / Q000502:physiology; D012919:Social Behavior