Towards a Better Understanding of Brain Anatomy in Autism Spectrum Disorder

Study could lead to the development of biomarkers and personalized treatments

Autism spectrum disorder (ASD) subjects are often amalgamated into one group, although they exhibit significant differences in the symptoms and severity of their disorder. Many studies on the subject have produced significantly different results, further blurring the leads when it comes to understanding and treating ASD.

However, a recently published study in Molecular Psychiatry set out to address some of the disagreements about brain anatomy in ASD. Led by researchers from McGill University's Faculty of Medicine and the Douglas Mental Health University Institute, the study is based on a large database.

"The most important results of our study are differences in the sources of heterogeneity," says Dr. Mallar Chakravarty, an assistant professor in the Department of Psychiatry at McGill University and lead author of the study. "For example, there are long-standing theories that girls with ASD must have a higher burden of risk before they develop symptoms. According to our data, the cortex is larger and thicker in most patients with ASD, but in girls it is even thicker and more closely related to the severity of the symptoms. "

To complete their study, the researchers used various sources, including public data from the ABIDE consortium. They also had access to data from a major international collaboration in the study of anatomical brain changes in ASD, which brings together a hospital in Canada (SickKids® of Toronto), an institute of the United States (National Institute of Mental Health) and two institutions in the United Kingdom (University of Cambridge and King's College).

Using magnetic resonance imaging (MRI), researchers have been able to examine the cerebral anatomy of 1327 neurotypic or autistic subjects, making this study one of the largest of its kind. "As part of our project, we have observed that the difference between the cortical anatomy of a TSA subject and that of a subject whose development is normal is not static," says Dr. Chakravarty, who is also Specialist in Computational Neuroscience at the Douglas Institute Brain Imaging Center. "Importantly, the major differences in symptomatology, severity of symptoms, cognition, age, and gender all stem from the brain differences seen in ASD alone. "

In addition, researchers found that the most pronounced cortical differences are found in the youngest children as well as those with the lowest cognitive abilities, as evidenced by their intelligence quotient.

For the future, researchers hope to gain an even more detailed profile of the sources of heterogeneity, including examining different types of symptoms - or creating subgroups based on symptoms - and concomitant medical issues. . They are also considering using novel techniques to examine the origin of changes in cortical variability at the microstructure level.

According to the researchers, this study is promising for the future. "Demonstrating variation in brain development with different known factors, such as age, gender, and cognitive abilities, suggests that some of these factors should be considered in future studies and eventually , in the diagnosis and treatment of ASD, "said Saashi Bedford, a McGill graduate student who works with Dr. Chakravarty and lead author of the study.