A new study published in Nature has discovered that the changes in the brain associated with autism are far more wide-reaching than experts previously believed.
The brain is now understood to undergo sweeping changes through the cerebral cortex rather than individual targeted areas, as previously believed. The study, conducted by the University of California, Los Angeles (UCLA), has wholly altered scientists’ understanding of autism spectrum disorder’s (ASD) progression at the molecular level.
Dr. Daniel Geschwind, study author and the Gordon and Virginia MacDonald distinguished professor of human genetics, neurology, and psychiatry at UCLA, said the study “represents the culmination of more than a decade of work of many lab members, which was necessary to perform such a comprehensive analysis of the autism brain.”
Unlike other neurological disorders like Parkinson’s disease or Alzheimer’s, ASD and other psychiatric disorders do not have a clear pathology. The new study, however, revealed that nearly all brain cortical regions are affected by ASD.
Whether language, reasoning, or mental flexibility, all functions are affected. In theory, the breakthrough will help experts develop more effective therapies for treating psychiatric disorders like autism.
Studying brain tissue after the death of 112 subjects with ASD, the researchers discovered that the visual cortex and the parietal cortex — responsible for processing pain, touch, and temperature — experienced the most significant drop in gene expression levels. They theorize that this might explain why sensory hypersensitivity is so common in people diagnosed with ASD.
The study also identified specific neuronal genes with diminished expression throughout the brain. They now believe RNA changes in the brain likely drive ASD rather than ASD triggering the RNA changes. As a next step, the scientists will leverage computer models to produce autism therapies modeled on reversing the gene expression in the brain.
Geschwind is encouraged by the findings. “We now finally are beginning to get a picture of the state of the brain, at the molecular level, of the brain in individuals who had a diagnosis of autism.”
This is beneficial, he said, because it “provides us with a molecular pathology, which, similar to other brain disorders such as Parkinson’s, Alzheimer’s, and stroke, provides a key starting point for understanding the disorder’s mechanisms, which will inform and accelerate the development of disease-altering therapies.”