title: Reduced relationship to cortical white matter volume revealed by tractography-based segmentation of the corpus callosum in young children with developmental delay.
abstract: OBJECTIVE
  The corpus callosum is the primary anatomical substrate for interhemispheric communication, which is important for a range of adaptive and cognitive behaviors in early development. Previous studies that have measured the corpus callosum in developmental populations have been limited by the use of rather arbitrary methods of subdividing the corpus callosum. The purpose of this study was to measure the corpus callosum in a clinical group of developmentally delayed children using a subdivision that more accurately reflected the anatomical properties of the corpus callosum.
  
  
  METHODS
  The authors applied tractography to subdivide the corpus callosum into regions corresponding to the cortical regions to and from which its fibers travel in a clinical group of very young children with developmental delay, a precursor to general mental retardation, in comparison with typically developing children.
  
  
  RESULTS
  The data demonstrate that the midsagittal area of the entire corpus callosum is reduced in children presenting with developmental delay, reflected in the smaller area of each of the fiber-based callosal subdivisions. In addition, while the area of each subdivision was strongly and significantly correlated with the corresponding cortical white matter volume in comparison subjects, this correlation was prominently absent in the developmentally delayed group.
  
  
  CONCLUSIONS
  A fiber-based subdivision successfully separates lobar regions of the corpus callosum, and the areas of these regions distinguish a developmentally delayed clinical group from the comparison group. This distinction was evident both in the area measurements themselves and in their correlation to the white matter volumes of the corresponding cortical lobes.
authors.affiliation: Department of Psychiatry, University of North Carolina, Chapel Hill, NC 27599-3367, USA.
authors.forename: Carissa
authors.initials: C
authors.lastname: Cascio
authors.forename: Martin
authors.initials: M
authors.lastname: Styner
authors.forename: Rachel G
authors.initials: RG
authors.lastname: Smith
authors.forename: Michele D
authors.initials: MD
authors.lastname: Poe
authors.forename: Guido
authors.initials: G
authors.lastname: Gerig
authors.forename: Heather C
authors.initials: HC
authors.lastname: Hazlett
authors.forename: Matthieu
authors.initials: M
authors.lastname: Jomier
authors.forename: Roland
authors.initials: R
authors.lastname: Bammer
authors.forename: Joseph
authors.initials: J
authors.lastname: Piven
mesh_terms: D001284:Atrophy; D001931:Brain Mapping / Q000379:methods; D002540:Cerebral Cortex / Q000473:pathology*; D002675:Child, Preschool; D003337:Corpus Callosum / Q000473:pathology*; D002658:Developmental Disabilities / Q000175:diagnosis* / Q000473:pathology; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D007839:Functional Laterality; D006801:Humans; D007223:Infant; D008297:Male; D015233:Models, Statistical; D009434:Neural Pathways / Q000473:pathology