Regeneration, Repair, and Developmental NeuroscienceResearch PaperSelectively diminished corpus callosum fibers in congenital central hypoventilation syndrome
Research highlights
▶We assessed corpus callosum (CC) fibers in CCHS, using DTI-based fiber tracking. ▶CC fiber injury appeared in specific, but not all areas projecting to cortices. ▶CC injury may underlie selected clinical deficits, especially ophthalmologic issues. ▶Injury may result from hypoxia or consequences of PHOX2B action in the syndrome.
Section snippets
Subjects
We studied 13 CCHS (mean age±SD: 18.2±4.7 years; age range: 7–23 years; body-mass-index±SD: 22.8±6.1 kg/m2; eight male) and 31 control (17.4±4.9 years; 7–24 years; 21.8±4.7 kg/m2; 18 male) subjects. These CCHS and control subjects were used in one previously-published manuscript (Kumar et al., 2010), dealing with other issues; that earlier manuscript described different types of tissue injury (axonal vs. myelin injury) in wide-spread brain areas in CCHS over control subjects. The CCHS diagnosis
Demographics
No significant differences in age (P=0.60), or body-mass-index (P=0.58) appeared between the CCHS and control groups. Significant sex difference did not emerge between the groups (P=0.83).
Corpus callosum fiber evaluation
The global CC fiber characteristics of CCHS and control subjects are summarized in Table 1, and individual fiber counts and density values are displayed in scatter plots (Fig. 2A, B). A substantial reduction in global CC fibers is visually evident in sample images of a CCHS and age- and sex-matched control
Overview
Global CC fiber counts and densities in CCHS were significantly reduced over control subjects, controlling for age and sex. These diminished fibers were localized within the CC in areas that project to prefrontal, premotor, parietal, and occipital regions. This study focused on using tractography procedures to outline interhemispheric characteristics of CC fibers. Other structural studies, including voxel-based T2-relaxometry and radial and axial diffusivity DTI procedures in CCHS subjects,
Conclusion
Global CC fibers are reduced in CCHS compared to control subjects. Regional reductions of fibers appeared in areas of the CC that serve interhemispheric communication for prefrontal, premotor, parietal, and occipital cortex, which are implicated in motor, speech, cognition, and ophthalmologic regulation; aspects of visuomotor and intrinsic eye control, as well as planning are especially affected in CCHS. The primary motor and temporal CC fibers are relatively spared in the condition. The
Acknowledgments
Authors thank Ms. Rebecca Harper and Mr. Edwin M. Valladares for assistance with data collection, Drs. Jennifer Ogren and Heidi Richardson for scientific editing, and Ms. Alexa Chavez for assistance with data analyses. We thank CCHS subjects and their parents/guardians for their participation in this study. This research was supported by the National Institute of Child Health and Human Development R01 HD-22695.
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