title: Plasticity of Interhemispheric Temporal Lobe White Matter Pathways Due to Early Disruption of Corpus Callosum Development in Spina Bifida.
abstract: Spina bifida myelomeningocele (SBM) is commonly associated with anomalous development of the corpus callosum (CC) because of congenital partial hypogenesis and hydrocephalus-related hypoplasia. It represents a model disorder to examine the effects of early disruption of CC neurodevelopment and the plasticity of interhemispheric white matter connections. Diffusion tensor imaging was acquired on 76 individuals with SBM and 27 typically developing individuals, aged 8-36 years. Probabilistic tractography was used to isolate the interhemispheric connections between the posterior superior temporal lobes, which typically traverse the posterior third of the CC. Early disruption of CC development resulted in restructuring of interhemispheric connections through alternate commissures, particularly the anterior commissure (AC). These rerouted fibers were present in people with SBM and both CC hypoplasia and hypogenesis. In addition, microstructural integrity was reduced in the interhemispheric temporal tract in people with SBM, indexed by lower fractional anisotropy, axial diffusivity, and higher radial diffusivity. Interhemispheric temporal tract volume was positively correlated with total volume of the CC, such that more severe underdevelopment of the CC was associated with fewer connections between the posterior temporal lobes. Therefore, both the macrostructure and microstructure of this interhemispheric tract were reduced, presumably as a result of more extensive CC malformation. The current findings suggest that early disruption in CC development reroutes interhemispheric temporal fibers through both the AC and more anterior sections of the CC in support of persistent hypotheses that the AC may serve a compensatory function in atypical CC development.
authors.affiliation: 1 Department of Psychology, University of Houston , Houston, Texas.|2 Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Kailyn A
authors.initials: KA
authors.lastname: Bradley
authors.affiliation: 3 Department of Pediatrics, Children's Learning Institute, University of Texas Health Science Center at Houston , Houston, Texas.
authors.forename: Jenifer
authors.initials: J
authors.lastname: Juranek
authors.affiliation: 3 Department of Pediatrics, Children's Learning Institute, University of Texas Health Science Center at Houston , Houston, Texas.
authors.forename: Anna
authors.initials: A
authors.lastname: Romanowska-Pawliczek
authors.affiliation: 1 Department of Psychology, University of Houston , Houston, Texas.
authors.forename: H Julia
authors.initials: HJ
authors.lastname: Hannay
authors.affiliation: 1 Department of Psychology, University of Houston , Houston, Texas.
authors.forename: Paul T
authors.initials: PT
authors.lastname: Cirino
authors.affiliation: 4 Program in Neurosciences and Mental Health, The Hospital for Sick Children , Toronto, Canada .
authors.forename: Maureen
authors.initials: M
authors.lastname: Dennis
authors.affiliation: 5 Department of Diagnostic and Interventional Radiology, University of Texas Health Science Center at Houston , Houston, Texas.
authors.forename: Larry A
authors.initials: LA
authors.lastname: Kramer
authors.affiliation: 1 Department of Psychology, University of Houston , Houston, Texas.
authors.forename: Jack M
authors.initials: JM
authors.lastname: Fletcher
mesh_terms: D000293:Adolescent; D000328:Adult; D061085:Agenesis of Corpus Callosum / Q000503:physiopathology; D016022:Case-Control Studies; D002648:Child; D003337:Corpus Callosum / Q000503:physiopathology; D056324:Diffusion Tensor Imaging / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008591:Meningomyelocele; D009413:Nerve Fibers, Myelinated; D009434:Neural Pathways / Q000503:physiopathology; D009473:Neuronal Plasticity / Q000502:physiology*; D016135:Spinal Dysraphism / Q000503:physiopathology*; D013702:Temporal Lobe / Q000503:physiopathology*; D066127:White Matter / Q000503:physiopathology*
keywords: corpus callosum; diffusion tensor imaging; fiber tracking; neural plasticity; temporal lobe