Reduced brain connectivity along the autism spectrum controlled for familial confounding by co-twin design
A recent study examined differences in brain connectivity between twins where one child is autistic and the other is not. The researchers used a brain imaging technique called diffusion tensor imaging (DTI) to map the connections between different parts of the brain. They studied 87 twin pairs, including identical (monozygotic) and fraternal (dizygotic) twins, some of whom were discordant for autism diagnosis.
The key findings were:
Twins with an autism diagnosis had reduced connectivity between the brainstem and a brain region involved in visual processing (the cuneus) compared to their non-autistic co-twins. This suggests differences in low-level visual processing.
The autistic twin had reduced connectivity between the hippocampus and regions involved in memory and face processing as opposed to the non-autistic twin. This points to differences in higher-order visual processing.
The differences were found even when controlling for genetic and environmental factors shared by the twins. According to the authors, this suggests the brain connectivity differences are specifically linked to autism traits and diagnosis.
There were some age and sex differences in the findings. For example, the autism diagnosis difference decreased with age, possibly reflecting compensatory brain changes.
Overall, the study found reduced brain connectivity in autism using a twin design that controlled well for potential confounding factors. The connectivity differences involve both lower-level sensory and higher-order social brain networks.
Study
Neufeld, J., Maier, S., Revers, M. et al. Reduced brain connectivity along the autism spectrum controlled for familial confounding by co-twin design. Sci Rep 13, 13124 (2023). https://doi.org/10.1038/s41598-023-39876-y