Brain changes in autism are more comprehensive than those affecting specific areas: study

PTI, November 4, 2022, 09:37 IST

Brain changes in autism are comprehensive throughout the cerebral cortex rather than specific areas believed to impact social behavior and language, a new study finds.

According to the study, it represents a global effort to characterize autism spectrum disorders (ASD) at the molecular level.

While neurological disorders like Alzheimer’s disease or Parkinson’s disease have well-defined pathologies or pathways, autism and other psychiatric disorders lack a definition of pathology, making it difficult to develop more effective, he said.

The study, led by the University of California, Los Angeles, reveals brain-wide changes in virtually all 11 cortical regions analyzed, whether associated with higher functions such as reasoning, language, social cognition and primary mental or sensory flexibility. Regions.

The results are published in Nature.

“This work represents the culmination of more than a decade of work by many members of the lab, which was necessary to perform such a comprehensive analysis of the brains of autistic people,” said study author Daniel Geschwind.

“We are finally starting to get a picture of the brain state, at the molecular level, of the brain in people who have been diagnosed with autism.

“This provides us with molecular pathology which, like other brain disorders such as Parkinson’s disease, Alzheimer’s disease and stroke, provides a key starting point for understanding disease mechanisms, which will inform and accelerate the development of disease-modifying therapies,” he said.

For this new study, the researchers examined gene expression in 11 cortical regions by sequencing RNA from each of the four major cortical lobes. They compared brain tissue samples obtained after death from 112 people with ASD with healthy brain tissue, according to the study.

While every profiled cortical region showed changes, the biggest drop in gene levels occurred in the visual cortex and parietal cortex, which processes information such as touch, pain and temperature. The researchers said this may reflect the sensory hypersensitivity commonly reported in people with ASD, according to the study.

The researchers also found strong evidence that genetic risk for autism is enriched in a specific neural module that has lower expression in the brain, indicating that RNA changes in the brain are likely the cause of ASD instead. than the result of the disorder.

Geschwind led the first effort more than a decade ago to identify the molecular pathology of autism by focusing on two regions of the brain, the temporal lobe and the frontal lobe. These regions were chosen because they are higher-order association regions involved in higher cognition – particularly social cognition, which is disrupted in ASD.

One of the next steps is to determine if researchers can use computational approaches to develop therapies based on reversing the gene expression changes that researchers have found in ASD, Geschwind said, adding that researchers can use organoids to model changes to better understand their mechanisms.