Autism Spectrum Disorders (ASD) are neurological disorders that affect the social relations and communication. They are also manifested by unusual behaviors (repetitive, in particular) and abnormal treatment of thesensory information in people who have it.
ASD: 650,000 people affected in France
ASDs, which encompassautism, the Asperger Syndrome or pervasive developmental disorder – unspecified (TED ‑ ns), would affect more than 3 million people in the European Union, including around 650,000 in France. One in 68 children would have ASD, according to recent estimates from the Center for Disease Control in the United States.
Using theMagnetic resonance imaging (IRM), a team of researchers, led by Andréas Frick of Inserm, observed, in a mouse affected by fragile X syndrome (a neurodevelopmental disorder closely linked to autism), an alteration of the connections and communication between different areas of the brain.
These new data, published on November 20, 2015 in the journal Science Advances, could explain certain symptoms of autism spectrum disorders such as hypersensitivity to sensory information or impaired visual perception. Also, these results agree with assumptions made for a long time.
ASD: disconnected areas of the brain on a global level
The theory of neuroscientists internationally suggests that the brains of people with ASD are “hyper-connected” at a local level, but that on a global scale, the different areas of the cortex are “disconnected” from each other. others.
Namely that in the brain, local connections process specific information (certain aspects of vision, for example) while connections at longer ranges allow the integration of more complex information (for example, the combination of different sensory information ). This last type of connection is necessary for a perception and a fine understanding of the external environment.
“Brain connections work like a highway”
“All of the brain connections work like a highway, allowing traffic to be distributed to different parts of an agglomeration, but also to other towns and villages outside,” explains Andréas Frick. The researchers wanted to take a closer look at the part of the neocortex, which processes visual information. The network in this part of the brain was different, with more connections coming from local sites, and few connections coming from distant networks. This could explain the altered sensory perception in sufferers.
This same team observed in 2014, in a study also carried out on model mice of ASD and fragile X, alterations in the way of reacting to sensory information (in particular information related to touch) and had described a mechanism explaining the neurobiological changes underlining this phenomenon.
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