Brain of Autistic Males Have Less Neurons For Emotions

A study has linked the autistic brains in males as having reduced amounts of neurons in the region that is related to emotional and socializing skills. This study was first reported in the July 19th issue of The Journal of Neuroscience.

The abnormality is found in the amygdala and especially in the lateral nucleus region of the brain. This region of the brain is the major center for processing emotions and is also connected to areas of the brain that is used for higher cognitive functions.

"These new findings, based on cell counting, complement other independent studies that suggest amygdala abnormalities likely contribute significantly to the primary core deficit in social function that defines this disorder," said Emanuel DiCicco-Bloom, MD, professor of pediatric neurology at the University of Medicine and Dentistry of New Jersey.


Authors Cynthia Schumann, PhD, of the University of California, San Diego, and David Amaral, PhD, director of the M.I.N.D. Institute at the University of California, Davis researched postmortem individual’s brains, both autistic and non-autistic. The scientists looked at the amygdala of nine autistic male brains and 10 age-matching non-autistic males. They counted and measured the neurons and found that neurons were less in the amygdala of the autistic male brains.

There is a paradox that showed during the use of magnetic resonance imaging which showed young males with autism had an abnormally large volume in the amygdala. This was surprising to the scientists to find that there were fewer neurons in the autistic amygdala.


Schumann thinks possibly that the amygdala was always functioning with less neurons in the autistic brain. It could also be a degenerative process that may cause a loss of neurons as a child with autism ages. Another possibility is that patients with autism often have a heightened level of stress and anxiety that may lead to loss of neurons over time. Further research needs to be conducted in order to pinpoint the exact reason the autistic brain has fewer neurons in the amygdala.

"We're in the very early stages of understanding autism and its neurological pathologies," said Amaral. "It's clearly a process with many steps, and at least we are now one step further."