Scientists have discovered that the region of the brain responsible for interpreting social cues among people who have been diagnosed with autism, differs depending on gender. They found that the region is unusually smooth in males, but normal in females. The findings of the study were published in a recent edition of the journal ‘Molecular Autism’ and add further evidence that autism is manifested differently according to whether you are male or female. These new results may offer an explanation for some of the difficulties experienced in social situations by boys with autism, in that the difference in the structure might make it more complicated for males to understand and interpret social interactions.
The study, which was led by Marie Schaer of Stanford University, was based on data from the Autism Brain Imaging Data Exchange (ABIDE). Although previous studies had already discovered subtle differences in the size and shape of various brain structures, the studies had been very small, with the largest based on just 60 people with autism. Utilising the data from ABIDE, Schaer and her colleagues were able to study patterns of the brain folds or gyri of 106 people with autism, ranging in age from 8-39.
In a typical brain, the structure becomes convoluted as it grows within the confines of the skull, a process which is normally completed by the end of the first year. However the cortex or brain’s outer layer continues to thicken until the child reaches early adolescence, before thinning out during adulthood. During Schaer’s research the brain of each participant was measured, including the volume, surface area and thickness. They also calculated the number and depth of cortical folds. They found that a region in the frontal lobe, which controls social motivation and helps to process social information, was smoother in the brains of males with autism, than that of autistic females or people without autism.
However, some of the conclusions drawn from the study have been treated with caution as the structure of the brain does change with age. Nevertheless, this is the largest study on the differences in brain structure of people with autism based on sex to date, and so has very important implications for both understanding what is going on in their brains, and also as a tool to inform further research.