Diffusion Tensor Imaging of the social brain in autism

Background:  

Autism spectrum disorders are now widely viewed as  neurodevelopmental disorders, although the underlying brain basis is not entirely clear. It is hypothesized that functional underconnectivity between regions comprising the mentalizing network contribute to the social impairments in autism, especially in the earlier cerebral development. 

Objectives:  

To examine aspects of the orbital and medial prefrontal cortices, the amygdala and lateral aspects of the temporal cortex are target region for the so called social brain.

Methods:  

Diffusion tensor imaging (DTI) was performed on 20 autistic children and healthy controls aged 6-12 years  matched for age, sex, handedness and IQ. We examined the functional and structural connectivity of key regions of the mentalizing network using DTI, fMRI and volumetric measure; in addition, DTI measures were correlated with cognitive and behavioural measures.

Results:  

Results  showed that there were significant differences in fractional anisotropy values between groups. Differences were less significant between individuals with higher IQ and lower symptom scores. 

Conclusions:

In summary, results suggest that disruption of white matter tracts  may contribute to impairments in social cognition in  autistic children. Moreover, differences may be more subtle in high functioning individuals.