Recall that autism is a behavioral disorder that is manifested by a mismatch in the family and social environment, and an inability to communicate with his environment. The exact causes of these disorders remain to be discovered. Today, over 60 years after the first description of autism, it is considered more appropriate to talk about “autism” to “autistic syndromes” or “pervasive developmental disorders”. There are, in fact, despite the existence of common characteristics, considerable heterogeneity between the autistic syndromes. Similarly, their evolution is highly variable, probably because of the plurality of probable cause.
It should be noted that these abnormalities, including white matter lesions are not specific to autism and are found in other mental disorders.
In addition, research conducted in 2004 by Monica Zilbovicius (INSERM-CEA), in association with the University of Montreal, showed that the autistic brain does not respond normally to the sound of the voice.
“We realized at Orsay with five autistic adults and eight healthy subjects, the same experiment was performed Belin4 Pascal. Knowing that half of autistic never manage to speak, we deliberately chose people who mastered the word, to avoid any bias due to non-language development. While observing their brain functional MRI, we listen to all subjects alternating sequences of human voice sounds (speech but shouts, laughter, songs) and other sounds (bell, motor, music, animal sounds). In all normal subjects, there was activation in the area of voice perception when it comes to vocal sounds when we do not score in autism. All, except one, have reacted in the same way the voice and other sounds. At the end of the test, we asked them what they had heard. Healthy subjects noted voices and non-vocal sounds while the only autism who remembered having heard an occasional voice was the one who turned the area of the voice during the examination. What can we conclude? Voice carries information about what the other thinks, especially through its intonations. We know that the basis of social interaction, it is the perception of the other person.
The autistic brain does not react like normal subjects facial expressions. Healthy subjects captures a lot of information through the emotion of a face – anger, laughter, sadness, etc.. In MRI, this translates into an activity area of the cortex called the “fusiform face area”. In autism, we did not observe any activation of this area. Thus, although it is neither blind nor deaf, autistic does not decode facial expressions, nor those of the voice. These two types of stimuli are closely related to social interaction.
According to researchers at INSERM-CEA, MRI is considered “a useful tool for the clinical assessment of autism” and “a new track for further research to investigate the neurological basis” of the disease.
These results show the importance of advancing research in the field of neuroscience, particularly brain imaging. Note that researchers do not have the results of their work as conclusions, but only as encouraging indications: “These data, from the analysis of magnetic resonance brain images (MRI) could help to distinguish in groups in autism and, thus, to advance research into the causes of the disease. It seems to be genetic factors in autism.
We also know that there are genetic factors. It is a certainty, as when there are two twins, the second twin, a highly significant proportion, has autism as the first, but not all twins. So it shows that the genetic factor weighs heavily, but is not the only explanation. All this adds up when it is not a specific explanation, and it is likely that there is currently under the terms of autism and pervasive developmental disorders, brain dysfunction is created by multiple causes where finally the different areas of the brain can not get functionally harmonious relationship with each other and, from this, trigger neuro-perceptual disturbances which I have spoken.
Robert Plomin, comportementale7 genetic specialist, says that for identical twins, if one is autistic, the other 65% probability of being, and much less twins. For them, the probability is around 15%. He added: “Three other studies have found similar results. They changed the autism research: since it is considered one of the most genetic disorders. Today, a dozen international studies trying to determine the genes for autism. And many aspects of behavior show a genetic influence. ‘
It therefore appears that progress in understanding the causes of autism, fault continue further research, both in the field of neuroscience than in genetics.