March 2016
&
GABA and Autism
Scientists have
speculated that
a lack of GABA
inhibition to
overexcited neurons could be the
underlying cause
of the hypersensitivity to sensory
input seen in
autism.
Harvard University and Massachusetts
Institute of Technology (MIT) neuroscientists
have identified a link between the activity of
the neurotransmitter GABA and symptoms of
autism. “This is the first connection in humans
between a neurotransmitter in the brain and an
autistic behavioral symptom,” said the study’s
lead author, Caroline Robertson, a post doc at
MIT’s McGovern Institute for Brain Research.
The GABA neurotransmitter inhibits brain cells
from firing in response to signals received from
the external environment to curb “runaway
excitation” in the brain, according to Roberts.
In other words, GABA tells neurons they
should stop firing and turn off. Scientists have
speculated that a lack of GABA inhibition to
overexcited neurons could be the underlying
cause of the hypersensitivity to sensory input
seen in autism. This hypersensitivity is the
biggest problem for those with autism. The
inability to tune out distracting sounds and
sensations make them feel overwhelmed.
Hypersensitivity also plays a role in the main
symptoms of autism: impaired social skills,
communication difficulties and repetitive
behaviors. Thus, it seems when GABA doesn’t
function properly, it is more difficult for the
brain to filter out environmental distractions.
Previous studies have linked reduced GABA
activity with autism-like behavior in animals, but
this is the first study to show the same results in
humans. Although the link has been established,
it is not known whether increasing GABA
activity could improve the symptoms of autism.
“It’ll be a longer story than just, ‘Aha! We’ll make
some GABA-enhancing drugs and cure autism,’”
said Robertson. “But it does point to a pathway
that seems to be dysfunctional in the autistic
brain.” The findings were published in the Dec.
17 issue of the journal Current Biology.
17