A Diffusion Tensor Imaging Study of the Social Brain in Autism

Background: It is hypothesized functional underconnectivity between regions comprising the mentalizing network contribute to the social impairments in autism, especially in the earlier cerebral development. Aspects of the orbital and medial prefrontal cortices, the amygdala and lateral aspects of the temporal cortex are target regions for the so called social brain.

Objectives: To investigate structural integritiy of white matter tracs in austistic children

Methods: Diffusion tensor imaging (DTI) was performed on 20 autistic children and 20 healthy controls aged 6-12 years matched for age, sex, handedness and IQ. We examined the structural connectivity of key regions of the mentalizing network using DTI and volumetric measures. In addition, fractional anisotropy (FA) values were correlated with symptom severity as indexed by the children’s scores on the Autisms Diagnostic Observation Schedule  (ADOS) and the Autism Diagnostic Interview-Revised (ADI-R).

Results: Results showed that there were significant differences of FA values between groups. Additionally, low FA values were inversely related to children’s ADOS and ADI scores in social interaction and communication, but not in the domain of repetitive and stereotypic behaviour.

Conclusions:

In summary, reductions in the structural integrity of white matter in autism are observable in young autistic children and may contribute to social and communication deficits of the disorder.