Autism is a very complex developmental disorder that could have many causes. Genetics and disrupted neurotransmission are thought to play a role in autistic symptoms.
One common symptom that may be present in autism is a slow rate of binocular rivalry.
What is Binocular Rivalry?
Binocular rivalry is a naturally occurring phenomenon of visual perception, where perception alternates between two different images presented simultaneously to each eye. The two eyes will compete for which image will be dominate, and will switch back and forth between images.
In a recent study by Robertson et al., researchers found that individuals with autism were shown to have a slower rate of binocular rivalry.
The autistic group had fewer changes in dominate images, they often saw a mixed perception of images, and their focus remained longer on a single image compared to the control group.
The ability to focus on a single image (when two are presented) is thought to rely on the suppression of one image by the visual cortex. This suppression by the visual cortex is thought to be mediated by the inhibitory neurotransmitter GABA.
Autism and GABA Levels in the Visual Cortex
In addition to testing the binocular rivalry of autistic individuals, Robertson and colleagues measured GABA levels in the visual cortex via magnetic resonance spectroscopy.
They found that higher concentrations of GABA corresponded with longer periods of perceptual suppression in control subjects (p=0.002).
However, this correlation was not found in autistic individuals, suggesting that GABA function in the visual cortex may be impaired with autism.
GABA Supplementation and Autism
It is not yet known if supporting GABA function with supplementation is beneficial for those with autism. Studies on the effectiveness of GABA supplementation for reducing autistic symptoms are warranted to determine if it has a positive effect.
Although we do not yet know if supporting GABA function can help improve autistic symptoms, we do know that GABA function in the visual cortex may be decreased in individuals with autism.
Reference
Robertson, C., Ratai, E., & Kanwisher, N. (2016). Reduced GABAergic Action in the Autistic Brain. Current Biology, 26(1), 80-85. doi:10.1016/j.cub.2015.11.019
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