Fewer connections between distant brain regions may explain why people with autism excel at some tasks, struggle with others
Researchers tracking the brain’s electrical cross-talk found a distinct pattern in children with autism spectrum disorder. Compared to children who didn’t have autism, those with the disorder had a surplus of brain activity within specific brain regions and fewer long-distance connections between different parts of the brain.
The study, which used electroencephalography (EEG) to track brain activity, appears online in the open-access journal BMC Medicine. It builds on previous research showing a similar, distinctive pattern of connections in brains affected by autism.
“This study helps us understand both the challenges and the strengths of people with autism,” says Autism Speaks Chief Science Officer Geri Dawson, Ph.D. “Complex behaviors such as social interaction require coordination among many different brain regions. If functional connectivity is reduced between regions, this helps explain why those behaviors are challenging for people with autism. By contrast, many people with autism excel at tasks that are more focused, such as memory, art and music, which may rely on more circumscribed brain regions.”
Recent studies have been examining whether treatments can alter patterns of brain activity in individuals with autism, Dr. Dawson adds. The techniques used in these studies offer a way to measure the impact of those treatments on the way the brain functions.
The researchers, from Boston Children's Hospital, used a "network analysis" technique similar to those used to study airline traffic and electrical grids.
The researchers analyzed EEG recordings from two groups of children with autism. Sixteen had autism of unknown cause. Fourteen had autism associated with a genetic syndrome called tuberous sclerosis complex (TSC). Many but not all with TSC also have autism. For comparison the researchers also analyzed EEGs from 29 children with TSC but not autism and 46 children without either disorder.
In both groups with autism, brain networks had a seeming surplus of short-range connections within different brain region and relatively fewer connections linking far-flung areas. The redundancy of pathways within brain regions is consistent with previous research showing that young brains affected by autism lack the normal "pruning" of extra connections that normally takes place in infancy.
"What we found may well change the way we look at the brains of autistic children," says Jurriaan Peters, M.D., who co-authored the report. "It's a simpler, less specialized network that's more rigid, less able to respond to stimulation from the environment." (See image above right.)
Autism Speaks continues to fund a broad range of studies on brain development and connectivity with the hope of advancing understanding of autism and the development of treatments and supports that can improve function and quality of life.
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