Autistic boys lack certain brain cells: study

WASHINGTON (Reuters) – Men and boys with autism have fewer
neurons in the amygdala, a part of the brain involved in
emotion and memory, U.S. researchers reported on Tuesday.

The team at the University of California, Davis, looked at
the brains of nine autistic men and boys, aged 10 to 44, and
compared them to 10 brains of males who did not have autism.

They counted the number of neurons to see whether the brain
cells were smaller or fewer in number.

Writing in the Journal of Neuroscience, David Amaral,
research director of the UC Davis Medical Investigation of
Neurodevelopmental Disorders Institute, and former graduate
student Cynthia Mills Schumann said they found significantly
fewer neurons in the brains of the people with autism.

“One possibility is that there are always fewer neurons in
the amygdala of people with autism. Another possibility is that
a degenerative process occurs later in life and leads to neuron
loss. More studies are needed to refine our findings,” Schumann
said in a statement.

In May, the U.S. Centers for Disease Control and Prevention
found that up to one in every 175 U.S. children has autism, a
disease that can cause symptoms ranging from social isolation
to repetitive and damaging behaviors and sometimes mental
retardation.

“While we have known that autism is a developmental brain
disorder, where, how and when the autistic brain develops
abnormally has been a mystery,” Dr. Thomas Insel, director of
the National Institute of Mental Health, which funded the
study, said in a statement.

“This new finding is important because it demonstrates that
the structure of the amygdala is abnormal in autism. Along with
other findings on the abnormal function of the amygdala,
research is beginning to narrow the search for the brain basis
of autism.”

Neurologists believe the amygdala is important in autism
because it generates appropriate emotional responses and helps
the brain process memories that are key to social learning.

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