• preschoolers
• imaging
• corpus callosum
• volume
• autism

The hypothesis of abnormal neural connectivity, involving short- and long-distance connections, is one of the most sustained pathophysiological theories of ASD. Recently, whole-brain analyses reconciled seemingly disparate themes of both hypo- and hyperconnectivity in the ASD literature, because both were detected, although hypoconnectivity seems to dominate, particularly for corticocortical and interhemispheric functional connectivity.
CC is the largest WM structure in human brain and it is the main connection and information transfer structure involved in interhemispheric communication. A growing body of literature has identified size reductions of the CC in subjects with ASD, and CC size also appears to be inversely related to autism severity and the intelligence quotient (IQ). However to date very few studies have been conducted on preschool age, when the disorder show its higher clinical expression.
The main goal of our study is to compare the CC volume between preschoolers with ASD and controls subjects. We analyzed CC subregions volume in both groups also.
Then, callosal size relations to demographic and clinical variables of ASD and control group (gender, age, non-verbal IQ, and language) have been examined.
Lastly, in the ASD group we assessed callosal volume relationship with autism severity.