For the first time ever, Harvard scientists have linked a specific neurotransmitter in the brain to autistic behaviour. The discovery could present valuable insights into diagnosing, understanding, and also the treatment of autism.
With the help of a visual test which prompts varying reactions in normal and autistic brains, a research team under the leadership of Caroline Robertson, a junior fellow has been able to explain that the differences were related to a breakdown in signalling pathway that was used by GABA, which is among the chief inhibitors of the brain – neurotransmitters.
In humans, this is also the first time that a neurotransmitter is linked to autistic behaviour. Robertson added that the theory of GABA signalling pathways playing a role in autism had earlier been shown in animal models. However, till now there was no evidence to show that it caused autistic differences in humans.
Robertson stated further that while the discovery may not influence autism treatments directly, it does offer precious insight into this disorder and explains the role played by neurotransmitters like GABA. The discovery suggests further that similar visual tests could be employed for screening younger children with symptoms of autism so that parents and clinicians could intervene sooner.
In animal models, GABA has been studied widely and was long believed to have a role in autism. Evidence to support the role of GABA in autism in humans had remained elusive.
Robertson went on to state that often, Autism is described as a disorder that causes all sensory inputs to come flooding in one go. Therefore, the idea of an inhibitory neurotransmitter made an important fit with clinical observations. Additionally, those who suffered from autism also have seizures and there is an amount of relationship between epilepsy and autism, and the researchers opine that the seizures represent runaway excitation within the brain.
In search of evidence, Robertson along with his colleagues searched for a test that was easily replicable while producing results that were consistently different for people without and with autism. Finally, they found the elusive evidence in what is known as binocular rivalry by visual neuroscientists. The brain typically is represented with two images marginally different from the other and those are one from each of the eyes, but they average to present the single image that we get to see. In the binocular rivalry test, however, each eye is forced to take in entirely different images, and the results were surprising.