title: In vivo quantification of global connectivity in the human corpus callosum.
abstract: Histological studies on nonhuman primates have shown a rich topography of homotopic (i.e., going to the same regions) or heterotopic (i.e., going to different regions) callosal projections. Unfortunately, a complete within-subject mapping of commissural projections in humans has been limited due to the inability of typical imaging methods to detect lateral projections in posterior cortical regions. Here, we set out to map callosal projection connectivity, at the single subject level (N=6), by combining high angular resolution diffusion weighted imaging and a novel multi-stage, region-of-interest (ROI) based fiber tracking approach. With these methods we were able to obtain a consistent increase in coverage of lateral projections to posterior cortical regions. Using 70 automatically segmented ROIs in each hemisphere and permutation statistics, we characterized significant interhemispheric connectivity patterns within each subject and observed: (1) consistent projections to frontal, parietal and occipital, but not temporal, areas, (2) a greater relative proportion of homotopic than heterotopic connections, and (3) commissural projections to the basal ganglia and thalamus that are consistent with human and nonhuman primate neuroanatomical literature. These results illustrate the first full connectivity analysis of the human corpus callosum, revealing several patterns consistent with histological findings in the nonhuman primate.
authors: Learning Research and Development Center, Department of Psychology, University of Pittsburgh, Pittsburgh, PA, USA.
authors: Kevin
authors: K
authors: Jarbo
authors: Timothy
authors: T
authors: Verstynen
authors: Walter
authors: W
authors: Schneider
mesh_terms: D000328:Adult; D001479:Basal Ganglia / Q000033:anatomy & histology / Q000502:physiology; D002540:Cerebral Cortex / Q000033:anatomy & histology / Q000502:physiology; D003337:Corpus Callosum / Q000033:anatomy & histology* / Q000502:physiology*; D003627:Data Interpretation, Statistical; D056324:Diffusion Tensor Imaging; D005260:Female; D005625:Frontal Lobe / Q000033:anatomy & histology / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D009412:Nerve Fibers / Q000502:physiology; D009434:Neural Pathways / Q000033:anatomy & histology / Q000502:physiology; D009778:Occipital Lobe / Q000033:anatomy & histology / Q000502:physiology; D010296:Parietal Lobe / Q000033:anatomy & histology / Q000502:physiology; D012984:Software; D055815:Young Adult