Kids with autism have a structural difference in brain connections compared to those without the disorder.
The finding, published in BMC Medicine, came from scientists from Boston Children’s Hospital who used EEGs to track the electrical cross-talk of the brain.
Previous research showed that the brains of adults with autism are “wired” differently from people without the disorder, and this abnormal pattern of connectivity may be the reason for the social impairments experienced by those with autism.
The new study indicated that autistic kids have multiple redundant connections between neighboring brain areas at the cost of long-distance associations, as opposed to those who are neurotypical.
The authors believe that the report, which used a “network analysis” similar to that used to examine electrical grids or airlines, might help experts better comprehend certain typical autistic behaviors.
Jurriaan Peters, MD, of the Department of Neurology at Boston Children’s Hospital, who is co-first author of the research, said: “We examined brain networks as a whole in terms of their capacity to transfer and process information. What we found may well change the way we look at the brains of autistic children.”
Peters, Maxime Taquet, a PhD student in Boston Children’s Computational Radiology Laboratory and co-first author, and team studied EEG recordings from two groups of kids with the disorder:
- 16 with classic autism
- 14 whose autism is part of a genetic syndrome known as tuberous sclerosis complex (TSC)
These recordings were then compared to EEGs from two control groups:
- 46 healthy neurotypical children
- 29 kids with TSC but not autism
More short-range connections within different areas of the brain were found in both groups of autistic kids, however, they had fewer connections linking far-flung regions.
A brain network that prefers short-range more than long-range connections appears to be constant with the typical cognitive profile of autism – a girl/boy who is extremely talented at certain tasks that require focus, such as memorizing streets, but who cannot combine information across various areas of the brain into higher-order ideas.
“For example, a child with autism may not understand why a face looks really angry, because his visual brain centers and emotional brain centers have less cross-talk. The brain cannot integrate these areas. It’s doing a lot with the information locally, but it’s not sending it out to the rest of the brain.”
Network analysis, a new branch of neuroscience, demonstrated a quality known as “resilience” in the autistic kids – the talent to come up with many ways to move from one point to the other through redundant pathways.
“Much like you can still travel from Boston to Brussels even if London Heathrow is shut down, by going through New York’s JFK airport for example, information can continue to be transferred between two regions of the brain of children with autism. In such a network, no hub plays a specific role, and traffic may flow along many redundant routes.”
This quality is compatible with cellular and molecular proof of reduced “pruning” of brain connections in autism.
Although airlines may benefit from this quality, it may suggest a brain that reacts in a comparable manner to several various types of circumstances and is less capable of focusing on the stimuli that are most critical.
“It’s a simpler, less specialized network that’s more rigid, less able to respond to stimulation from the environment,” revealed Peters.
According to the results, all of the kids with tuberous sclerosis complex had an overall decreased connectivity, but the pattern of increased short-range vs. long-range connections was only seen in those who were also autistic.
As part of a multicenter investigation, Peters and his co-workers will do the examination another time and take EEG recordings prospectively under identical conditions, with the help of the NIH Autism Center of Excellence Grant.
The new research adds to recent work of Peters, Sahin, and team which imaged nerve fibers in people with autism and demonstrated structural malformations in brain connectivity.
One study at Boston Children’s, led by Frank Duffy, PhD, of Neurology, analyzed the degree of synchrony between any two given EEG signals, referred to as “coherence”, and saw modified connectivity between autistic kids’ regions of the brain.
A different report recently conducted by Boston Children’s informatics researcher William Bosl, PhD, and Charles A. Nelson, PhD, research director of the Developmental Medicine Center, examined an indirect measure of connectivity – the degree of randomness in EEG signals – and discovered patterns that differentiated infants with a higher risk for autism from controls.
Written by Sarah Glynn