Thursday, May 7, 2009

Researchers Put Another Piece of the Autism Puzzle in Place


What has more than 65 years of research uncovered about autism? Not its cause, not a cure, not a means to prevent it, not a fully effective treatment. Researchers have identified a number of genes associated with the disorder and some studies suggest that people with autism have abnormal levels of serotonin and other neurotransmitters in the brain. Other studies of people with autism have found irregularities in several regions of the brain. But intriguing new research by scientists at the University of North Carolina actually pinpoints the time when these brain anomalies occur, findings that experts say are critical in developing new ways to treat and diagnose autism earlier.

For the study, Dr. Matthew W. Mosconi and his colleagues at UNC took magnetic resonance imaging (MRI) scans of 50 children with autism and 33 controls—22 typically developing children and 11 who were developmentally delayed—between 18 and 35 months and again between 42 and 59 months. Participants also underwent tests that looked for certain behavioral features of autism. The researchers found that at both time points, the amygdala region of the brain, which is associated with controlling emotions, regulating attention and reading social cues from eye contact, in the children with autism was larger than the toddlers in the control group. “The amygdala plays a critical role in early-stage processing of facial expression and in alerting cortical areas to the emotional significance of an event,” the authors wrote. “Amygdala disturbances early in development, therefore, disrupt the appropriate assignment of emotional significance to faces and social interaction.”

The researchers said after observing the children that the enlarged amygdala appeared consistent with something called joint attention, or the ability of a young child to follow another person’s gaze and to share attention with others; behaviors thought to predict later social and language function. “We would basically try to get the child to look one way, we’d turn and point to a clock and see whether or not the child would notice it,” explained Dr. Joseph Piven, director of UNC’s Neurodevelopmental Disorders Research Center and one of the study’s authors. “The two-year-olds without autism would see your face, see where you are looking and join you but the children with autism, with large amygdalas, would not.”

“We believe that children with autism have normal-sized brains at birth but at some point, in the latter part of the first year of life, it (the amygdala) begins to grow in kids with autism,” said Piven. “Once we understand the neurological circuits, we may be able to detect if a child has problems in those circuits as early as 6 months of age. We need to let the pattern of early brain development guide us to predict who is at higher risk and who would benefit from early intervention.”

The team continues to follow study participants to determine whether amygdala growth rates continue at the same rate, speed up or slow down in children with autism after age four. “Studying this relationship as these children develop will shed important light on the neurobiological basis of autism,” Piven said. UNC researchers are also recruiting 500 infants who are also sibling of children with autism for a follow-up to their initial findings. “By tracking the behaviors and brain volume growth from birth in high-risk babies, we can pinpoint when the brain first begins to grow larger than normal and provide therapy or medications to limit the growth or symptoms a lot earlier than we are doing now,” said Piven.

“What they’re doing at UNC is really starting to define in the brain what’s going on with someone who has autism,” said Scott Badesch, chief executive of the Autism Society of North Carolina. “That gives us an ability as providers to address those needs.” Badesch said recent scientific findings, including an announcement last week about a new genetic clue for up to 15 percent of cases, are offering hope to families struggling with the disorder. “We’re beginning to find things, and the next question is what, if anything, we can do regarding treatment or a cure.”


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