title: Novel inter-hemispheric white matter connectivity in the BTBR mouse model of autism.
abstract: Alterations in the volume, density, connectivity and functional activation of white matter tracts are reported in some individuals with autism and may contribute to their abnormal behaviors. The BTBR (BTBR T+tf/J) inbred strain of mouse, is used to model facets of autism because they develop low social behaviors, stereotypical and immune changes similar to those found in people with autism. Previously, it was thought a total absence of corpus callosal interhemispheric connective tissues in the BTBR mice may underlie their abnormal behaviors. However, postnatal lesions of the corpus callosum do not precipitate social behavioral problems in other strains of mice suggesting a flaw in this theory. In this study we used digital pathological methods to compare subcortical white matter connective tracts in the BTBR strain of mice with those found in the C57Bl/6 mouse and those reported in a standardized mouse brain atlas. We report, for the first time, a novel connective subcortical interhemispheric bridge of tissue in the posterior, but not anterior, cerebrum of the BTBR mouse. These novel connective tissues are comprised of myelinated fibers, with reduced myelin basic protein levels (MBP) compared to levels in the C57Bl/6 mouse. We used electrophysiological analysis and found increased inter-hemispheric connectivity in the posterior hemispheres of the BTBR strain compared with the anterior hemispheres. The conduction velocity was slower than that reported in normal mice. This study shows there is novel abnormal interhemispheric connectivity in the BTBR strain of mice, which may contribute to their behavioral abnormalities.
authors.affiliation: Wadsworth Center for Laboratories and Research, New York State Department of Health, Empire State Plaza, Albany, NY 12201-0509, USA. vmiller@wadsworth.org
authors.forename: V M
authors.initials: VM
authors.lastname: Miller
authors.forename: D
authors.initials: D
authors.lastname: Gupta
authors.forename: N
authors.initials: N
authors.lastname: Neu
authors.forename: A
authors.initials: A
authors.lastname: Cotroneo
authors.forename: C B
authors.initials: CB
authors.lastname: Boulay
authors.forename: R F
authors.initials: RF
authors.lastname: Seegal
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001321:Autistic Disorder / Q000473:pathology*; D001921:Brain / Q000002:abnormalities / Q000473:pathology*; D003337:Corpus Callosum / Q000473:pathology*; D004195:Disease Models, Animal; D004569:Electroencephalography; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D007839:Functional Laterality; D007091:Image Processing, Computer-Assisted; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008818:Mice, Neurologic Mutants; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D004676:Myelin Basic Protein / Q000378:metabolism; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D059906:Neuroimaging; D013057:Spectrum Analysis
chemical_list: D008869:Microtubule-Associated Proteins; D004676:Myelin Basic Protein