Landmark Study Identifies Key Brain Difference In Autism

But we’ve never found a neurotransmitter involved in autism before, and this is a major breakthrough in the sense that, symptom or cause, we’re beginning to understand a formerly impenetrable disease. Specifically, researchers used a binocular-rivalry test, in which both eyes are forced to take in different information at one time. In addition to opening up the possibility of new drugs that target GABA pathways, clinicians might also one day be able to examine GABA activity in early screenings for autism. “So the idea that an inhibitory neurotransmitter was important fit with the clinical observations”.

“I’m excited about this study, but there are many other molecules in the brain, and many of them may be associated with autism in some form”, she said. Similarly, this may be a symptom of autism, not a cause; more testing will need to be done, and work on restoring GABA channels is in its infancy at best.

Robertson explained that what happens is that one image gets suppressed from visual awareness for a short period of time, then as the neurons that suppress the image get exhausted, vision will switch to the other image.

Though it was suspected for a long time that GABA has a role to play in autism, there was no evidence till now.

The researchers have used brain imaging and a visual test that leads to different reactions in the brains of people having autism and those without the same.

The role of the GABA neurotransmitter is to inhibit brain cells from firing in response to signals received from the external environment – or as Robertson told The Huffington Post, to curb “runaway excitation” in the brain.

“It’s clear that there are changes in brain vascularization in autistic individuals from two to 20 years that are not seen in normally developing individuals past the age of two years”, says Azmitia. Using scans of the brain, the scientists found the lack of the inhibitor GABA, which was not functioning properly, essentially leads to a flood of information. Eventually, the brain “rocks” back and forth between the two different images so that you see a different image every so often.

In earlier studies, Robertson and colleagues showed that while the same process does occur in the autistic brain, the process of oscillating between images can take significantly longer. Here, they discovered a strong link between binocular rivalry dynamics and levels of GABA in the participants who had not been diagnosed with autism. “It’s not that there’s not GABA in the brain… it’s that there’s some step along that pathway that’s broken”.

“What we think we’re seeing is evidence of a deficit in the GABA-ergic signaling pathway”, Robertson said.

“In a typical brain, blood vessels are stable, thereby ensuring a stable distribution of blood”, adds Azmitia, also an adjunct professor at NYU School of Medicine’s Department of Psychiatry.