Rose
Lincoln/Harvard Staff Photographer
“This is the first
time, in humans, that a neurotransmitter in the brain has been linked to
autistic
behavior — full
stop,” said Caroline Robertson, a junior fellow of the Harvard Society of
Fellows.
(December 17, 2015)
Scientists find neurotransmitter that ties in with disorder’s behavior.
In a discovery that could offer valuable insights into understanding,
diagnosing, and even treating autism, Harvard scientists for the first time
have linked a specific neurotransmitter in the brain with autistic behavior.
Using a visual test that prompts different reactions in
autistic and normal brains, a research team led by Caroline Robertson, a junior
fellow of the Harvard Society of Fellows, was able to show that those
differences were associated with a breakdown in the signaling pathway used by
GABA, one of the brain’s chief inhibitory neurotransmitters. The study is
described in a Dec. 17 paper in the journal Current Biology.
“This is the first time, in humans, that a neurotransmitter
in the brain has been linked to autistic behavior — full stop,” Robertson said.
“This theory that the GABA signaling pathway plays a role in autism has been
shown in animal models, but until now we never had evidence for it actually
causing autistic differences in humans.”
Though it may not lead directly to autism treatments,
Robertson said the finding offers invaluable insight into the disorder and the
role that neurotransmitters such as GABA may play in it. The discovery also
suggests that similar visual tests could be used to screen younger children for
autism, allowing parents and clinicians to intervene sooner.
Though long believed to play a role in autism — GABA has
been widely studied in animal models — evidence supporting GABA’s role in the
disorder in humans has been elusive.
“Autism is often described as a disorder in which all the
sensory input comes flooding in at once. So the idea that an inhibitory
neurotransmitter was important fit with the clinical observations,” Robertson
said. “In addition, people with autism often have seizures — there is a 20 to
25 percent comorbidity between autism and epilepsy — and we think seizures are
runaway excitation in the brain.”