Reduced Size of Corpus Callosum in Autism

Reduced functional connectivity between V1 and inferior frontal cortex associated with visuomotor performance in autism

“…MRI volumetric studies have shown early overgrowth of parietal white matter in autistic children up to age 4 years (Carper et al, 2002) and abnormally large radiate compartments in parietal white matter in older children (Herbert et al, 2004). Reduced size in posterior subregions of the corpus callosum connecting bilateral parietal lobes (Egaas et al, 1995) would further indicate anomalies of connectivity in the autistic parietal lobe. The absence of significant group differences in parietal areas in our fcMRI study may suggest that these anomalies do not primarily affect connectivity between V1 and parietal lobes.…”

Abnormal early brain development in autism

“…Lastly, posterior regions of the corpus callosum are also reduced in size in autism in a study of 3 to 42-year-olds. 10 In conclusion, these recent MRI observations suggest abnormal regulation of brain growth in autism: overgrowth early in life followed by abnormally slowed growth in some regions, but premature arrest of growth in others. This evidence raises a growth dysregulation hypothesis of autism in which there is a pathologic dysregulation in the timing and amount of growth as well as in the cessation of growth.…”

Less white matter concentration in autism: 2D voxel-based morphometry

“…Autism is a neurodevelopmental disorder of brain function that has begun to attract in vivo structural magnetic resonance imaging (MRI) studies in the region of the corpus callosum (Egaas et al, 1995, Hardan et al, 2000Manes et al, 1999;Piven et al, 1996Piven et al, , 1997. There is little understanding about the link between the functional deficit and the underlying abnormal anatomy in autism, which provides motivation for our study.…”