Genetic changes are almost certainly behind many cases of autism, and the latest research suggests that some of those alterations may be contributing to more densely connected networks of brain nerves.
A highly interconnected brain could mean that signals zooming from sensory nerves to other networks become too overwhelming to parse apart and process, which researchers believe is a hallmark of the autistic brain. And in a study published in JAMA Psychiatry, Stanford University researchers report that this pattern of hyperconnectivity in some brain areas could provide a fingerprint for autism that helps doctors to recognize the condition at its earliest stages.
The scientists scanned the brains of 20 autistic children who ranged in age from 7 to 12 and also imaged 20 typically developing children of the same age for comparison. They found stronger connections within many critical brain networks in the autistic children, including those responsible for introspection, vision and movement.
They also saw more robust links in networks that help the brain to triage the flood of incoming information from both our bodies and our environment that assaults us constantly. Called the salience network, it’s responsible for determining which internal or external sensations need our immediate attention. Using a computer program that the researchers developed to make sense of the brain imaging data, they found that by mapping the salience network alone, they could accurately classify autistic or non-autistic children in their study 78% of the time — and could do so 83% of the time using data from other researchers.
“That’s wonderful,” says Kamila Markram, the Autism Project Director at the Brain Mind Institute of the EPFL, a federal technology institute in Lausanne, Switzerland, who was not associated with the research, “We must move toward biological markers for autism and not just rely on interviews and observations by people.” Markram previously published animal research suggesting that hyperconnectivity may be involved in autism.
Moreover, the more strongly connected the salience network was in autistic children, the worse symptoms they had in terms of repetitive behaviors like rocking and restricted interests such as being obsessed with computers or the periodic table of elements. The findings suggest that from an early age, children with autism develop differently from those without the condition, and that these changes may be detectable through brain imaging.
Hyperconnection could explain both the behavioral deficits associated with autism as well as some of its more positive outcomes. A more highly connected brain, for example, is prone to information overload, which can lead to social withdrawal, restricted interests and repetitive behavior as ways of escaping or coping. But such enmeshed neural networks may also lead to better memory and greater focus.
“It confirms the hypothesis and theories we suggested in our model,” says Markram, whose work in rats showed that exposure at specific times during fetal development to the epilepsy drug valproic acid (VPA), or Depakote, contributed to hyperconnected brains and autism-like symptoms. That led her to develop the ‘intense world’ theory that sees autism as resulting from an overwhelmed brain that is taking in and processing too much information.
According to the theory, the repetitive and obsessive focus that some autistic patients develop toward specific behaviors could be a coping mechanism for this information overload. “Because the [autistic] brain is not adaptively focusing on responding to external information, it can focus on a narrow range of interests,” says the study’s lead author Vinod Menon, a professor of child and adolescent psychiatry at Stanford. “That kind of focus is actually what could give rise to these outstanding but restricted areas of exceptional skill.” He adds that his new research “opens up a nice way of thinking about how the brain is organized that can lead to both deficits and strengths.”
Recognizing a unique autistic brain pattern could also identify children at higher risk of developing the condition well before the first symptoms appear, generally around two years old. Recent studies suggest that intervening with behavioral therapies that help toddlers to learn how to process information in a more organized fashion could reconstruct potentially abnormal networks of brain neurons. And further research may refine these therapies to the point where they could help autistic people to enhance their creative skills and ability to concentrate and mitigate their more unhealthy behaviors.