Friday, March 30, 2018 (HealthDay News) – Neurons in a brain area that are involved with social and emotional behavior usually increase as children grow up, but this does not occur in people with autism, new research claims.
Instead, children with Autism Spectrum Disorder (ASD) have too many neurons in this part of the brain – the amygdala – and lose neurons when they mature, according to researchers from the MIND Institute at the University of California at Davis  "Amygdala is a unique brain structure, as it increases dramatically during adolescence, longer than other brain regions, as we mature socially and emotionally," senior author Cynthia Schumann said in a university press release.
"Any deviation from this normal path of development can fundamentally affect human behavior," she said. Schumann is Associate Professor of Psychiatry and Behavioral Sciences.
For the study, Schumann's team examined the brains of 52 people who died, including some with autism. They ranged in age from 2 to 48 years.
The researchers were surprised that the number of neurons in one part of the amygdala in normally developed individuals increased by more than 30 percent from childhood to adulthood
people with autism, but the number of neurons was higher than normal in small children and declined with age.
"We do not know if too many amygdala neurons are associated with apparent loss at the beginning of ASD development," Schumann said.
"It is possible that too early neurons can contribute to fears and challenges with social interactions, but over time, this constant activity could damage the system and lead to neuronal loss," she said.
Learning more about how neurons in the amygdala change during adolescence may, according to the researchers, lead to new therapies for autism and other brain diseases.
Previous studies have linked amygdala dysfunction to disorders such as autism, schizophrenia, bipolar disorder and depression. 1
The US Centers for Disease Control and Prevention have focused more on autism Spectrum Disorder
SOURCE: University of California, Davis, Press Release, March 20, 2018