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A research team led by Dartmouth identified a neural marker of autism, nonverbal. This marker shows that people with autism are slower to dampen neuronal activity in response to visual cues in the brain. This unique marker has been shown to be independent of intelligence and is an objective way to potentially diagnose autism in the future. The results are published in Current biology.

"Autism is difficult to detect in children when the first signs are present. A qualified clinician may be able to detect autism at 18 months or even earlier; yet, the average age of a diagnosis of autism in the United States is about four years. years, "says lead author Caroline Robertson, assistant professor of psychological and brain sciences at Dartmouth and director of Dartmouth Autism Research." We need objective and non-invasive screening tools that do not depend on assessing the behavior of a child. One of the main goals of the field is to develop objective neural markers of autism that can work with non-verbal individuals. This neural marker is just that, "she added.

It has long been thought that people with autism inhibit neuronal signals in the brain. It is thought that this underlies the symptoms of autism, such as hypersensitivity to sensory inputs, which includes differences in the processing of visual information.

When the human brain is presented with two different images at the same time, the images flip into consciousness, flipping between the left eye and the right eye. Previous research conducted by Robertson has shown that the autistic brain tilts more slowly from one image to another (also known as slower binocular rivalry) because of the differences in inhibitory neuronal transmission in the brain . In the autistic brain, the neurotransmitter, GABA, has difficulty in filtering and regulating sensory signals, including in this case, to remove one of the images.

The new study used brain imaging to measure the slower pace of binocular rivalry in people with autism. With these results, the research team was able to accurately determine if participants were autistic and predict the severity of autism symptoms, which were measured with the help of of traditional clinical evaluations.

To obtain neuronal data, the study measured cerebral signals from a single electroencephalographic (EEG) electrode placed on the participant's head, above the visual region of the brain. Participants were presented with one of two visual images: a red checkerboard in the left eye and a green checkerboard in the right eye that flickered at different rates.

The research revealed that neural data could be used to predict whether an individual was autistic with an accuracy of 87%. The results were striking and followed up with clinical measures of autism: participants with a higher level of autism had a slower binocular rivalry rate, the brains slowing the shift from an image to autism. l & # 39; other.

The research offers a new promise for how autism is diagnosed. "This visual test can be a non-verbal marker of autism in adults. We will then determine whether this test could possibly be used to detect autism in pre-verbal children and non-verbal adults and make it a screening tool. Meanwhile, this result gives us a new view of the brain in the autism, showing that the visual regions of the brain are affected. "The researchers also noted that the visual sensitivities of people with autism differed significantly from one autistic spectrum to the other. therefore, although measuring these differences in visual processing may not detect autism in all individuals, it may contribute to a better understanding of the autistic spectrum.

The brain clock turns differently in autism

More information:
Current biology (2019).… 0960-9822 (19) 30871-1

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Dartmouth College

New study shows how to measure autism by means of a nonverbal marker (August 15, 2019)
recovered on August 15, 2019

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