Emerging research shows that children with autism spectrum disorder have a structural difference in brain connections from children without ASD.
Investigators from Boston Children’s Hospital discovered children with autism have multiple redundant connections between neighboring brain areas at the expense of long-distance links.
In the study, researchers used electroencephalographs (EEG) to measure electronic voltage fluctuations resulting from the brain’s electrical cross-talk.
Investigators used a “network analysis” approach similar to that used to study airlines or electrical grids.
The research, accompanied by a commentary is found in BioMed Central’s open access journal BMC Medicine.
“We examined brain networks as a whole in terms of their capacity to transfer and process information,” says Jurriaan Peters, MD, of the Department of Neurology at Boston Children’s Hospital.
“What we found may well change the way we look at the brains of autistic children.”
Peters, Maxime Taquet, and senior authors Simon Warfield, PhD, and Mustafa Sahin, MD, PhD analyzed EEG recordings from two groups of autistic children: 16 children with classic autism, and 14 children whose autism is part of a genetic syndrome known as tuberous sclerosis complex (TSC).
They compared these readings with EEGs from two control groups — 46 healthy neurotypical children and 29 children with TSC but not autism.
In both groups with autism, there were more short-range connections within different brain region, but fewer connections linking far-flung areas.
A brain network that favors short-range over long-range connections seems to be consistent with autism’s classic cognitive profileâ€”a child who excels at specific, focused tasks like memorizing streets, but who cannot integrate information across different brain areas into higher-order concepts.
“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,” Peters says.
“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 cognitive neuroscience — showed a quality called “resilience” in the children with autism — the ability to find multiple ways to get from point A to point B 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,” says Taquet.
“In such a network, no hub plays a specific role, and traffic may flow along many redundant routes.”
This quality of redundancy is consistent with cellular and molecular evidence for decreased “pruning” of brain connections in autism. While it may be good for an airline, it may indicate a brain that responds in the same way to many different kinds of situations and is less able to focus on the stimuli that are most important.
“It’s a simpler, less specialized network that’s more rigid, less able to respond to stimulation from the environment,” says Peters.
The study showed that both groups of children with tuberous sclerosis complex had reduced connectivity overall, but only those who also had autism had the pattern of increased short-range versus long-range connections.
The current study builds on emerging research which imaged nerve fibers in autistic patients and showed structural abnormalities in brain connectivity.
Source: Boston Children’s Hospital