Scientists have discovered a direct link between autistic behavior and the neurotransmitter GABA.
In the study published by the scientific journal Current Biology, researchers at MIT and Harvard University located a processing deficiency in autism patients that prevents the brain from blocking the inhibitory neurotransmitter amma-Aminobutyric acid (GABA), which prevents brain cells from acting in response to superfluous information received from the senses.
“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,” said Caroline Robertson, the lead researcher.
While many of us can simply tune out everyday sights or sounds—say, the sight of a grate on the sidewalk or the noise of a car driving by—those with autism are inundated with a deluge of sensory information that can turn everyday environments into distressing experiences.
The GABA inhibitor is also critical in discerning the different types of images of which the brain interprets on a daily basis. According to Mother Jones, researchers used a visual test to study each participant’s ability in distinguishing objects while shutting out the others from view.
Looking through binoculars, they would see two different images in both eyes—say, a house on the left side and a car on the right side. Most people can focus on one image while diminishing focus on the other, and then switch, oscillating back and forth between the car and the house. In essence, inhibitory neurotransmitters enable the brain to process digestible pieces of information rather than try to take in everything at once.
Autistic patients tend to have a difficult time with processing image oscillations, with the ability to focus on one image being less directed. When the participants were scanned with a neuro-imaging device, a correlation between GABA levels and test scores was discovered – the more GABA they have, the greater the chance at scoring high on visual acuity.
The study also showed that all the autistic participants who were better at visual processing had no higher or lower levels of GABA than those who weren’t. Which may suggest a break down somewhere in the GABA inhibiting process.
“It’s not that there’s no GABA in the brain,” said Robertson, “It’s that there’s some step along that pathway that’s broken.”
Researchers hope the new discovery with lead to better medication that can target the GABA neuro-pathways, therefore reducing some of the background noise in autism patients. However, Robertson warns that this breakthrough is not a sliver bullet in curing the condition.
“There are many other molecules in the brain, and many of them may be associated with autism in some form,” she said. “We were looking at the GABA story, but we’re not done screening the autistic brain for other possible pathways that may play a role.”
Featured image via Flickr