UCLA scientists have found that in young people with high-functioning autism spectrum disorder, the areas of the brain that are linked to social behaviors are both less developed and less-sufficiently networked than they are in young people without autism.
The findings were published online by the peer-reviewed journal Brain and Behavior.
“The brain controls most of our behavior and changes in how brain areas work and communicate with each other can alter this behavior and lead to impairments associated with mental disorders,” said Kay Jann, the study’s first author, and a postdoctoral researcher in the UCLA department of neurology. “When you match physiologic changes in the brain with behavioral impairment, you can start to understand the biological mechanisms of this disorder, which may help improve diagnosis and, in time, treatment.”
The researchers used imaging technology that tracks both blood flow in the brain —a measure of the brain’s energy use — and the organization and strength of connections within intrinsic neural networks. It marked the first use of an MRI tool known as arterial spin labeling perfusion to study autism. Researchers also refined existing technology to assess how well separate areas of the brain are functionally interconnected. Both techniques are noninvasive.
Investigators studied 17 people with high-functioning autism and 22 without. Participants ranged in age from 7 to 17.
The researchers also discovered less long-range connectivity between default mode network nodes in the front and back of the brains among those with ASD, compared to typical brains. The loss of connectivity means that information cannot flow as it should between distant areas of the brain, which might explain impairment in social responsiveness, Jann said.
“The architecture of the brain follows a cost-efficient wiring pattern that maximizes functionality with minimal energy consumption,” he said. “This is not what we found in our … participants [with autism].”
The study was supported by grants from the National Institute of Child Health and Human Development (P50 HD055784), National Institute of Mental Health (1R01-MH080892), the International Mental Health Research Organization. Jann has a fellowship funded by the Swiss National Science Foundation and the Swiss Foundation for Grants in Biology and Medicine.
The research team consisted of scientists from the UCLA Ahmanson–Lovelace Brain Mapping Center, as well as the UCLA department of psychiatry and biobehavioral sciences.
- Kim Irwin