Autism Spectrum Disorders (ASDs) are caused by developmental disruptions characterized by communication disorders, altered social interactions and sensory and behavioural abnormalities. Research in genetics and brain imaging suggests that alterations in brain development, including the formation of neural networks and the functioning of synapses, may contribute to the development of ASDs.

In recent years, neuroimaging studies have shown that people with ASDs have abnormalities in the functioning of certain brain areas known to be responsible for processing emotions, language or social skills. Research on the brain connectivity of people with ASD has shown in particular a lack of "long distance" connections in contrast to an increase in "short distance" connectivity. These results formed the basis for the development of a theoretical model for understanding ASDs, according to which the lack of social attention and information processing (difficulty in understanding a situation as a whole, attention to detail) is explained by an oversaturation of information processed within the brain, linked to the increase in neural connectivity between adjacent brain areas.

However, Professor Josselin Houenou, Professor of Psychiatry at the UPEC, Inserm U955, a practitioner at the Henri Mondor University Hospitals and a researcher at NeuroSpin, points out: "this model is based on the study of heterogeneous paediatric populations, including autistic children of variable ages and very varied symptomatology, and on non-specific neuroimaging methods that do not allow reliable measurement of connectivity"'short distance". »

At this point, an innovation from the Human Brain Project (HBP) provided a way to test the current model. Within the HBP, scientists throughout Europe collaborate to integrate vast amounts of neuroscientific data into the most comprehensive model of the brain to date as a resource that is open to scientists and clinicians worldwide. Neurospin is one of the central partner institutions in this endeavor. As part of the work scientists Miguel Guevara, Jean-François Mangin and Cyril Poupon from NeuroSpin had created an atlas specifically dedicated to the tractography of 63 "short distance" connections from images obtained by diffusion MRI (dMRI). This method allows highlighting the white matter fibres of the brain in vivo by measuring the diffusion of water molecules, especially along axons. It is then possible by tractography to reconstruct the paths of the nerve fibre bundles represented in the form of a tractogram.