Brain wiring in the Fragile X model of autism

What is it about?

One theory suggests that the neocortex of individuals with autism spectrum disorder (ASD) are ‘hyper-connected’ on a local level, but that on a global scale different neocortical areas are functionally ‘disconnected’ from one-another. Using a combination of diffusion tensor magnetic resonance imaging (MRI), viral based tracing of connections together with whole-brain imaging, and resting-state MRI, we provide experimental evidence for this hypothesis.

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Why is it important?

Our work not only confirms the long-standing hypothesis (mentioned above), but it also provides an explanation for some of the symptoms of ASD and Fragile X Syndrome, for example hypersensitivity to sensory information, enhanced processing of local information and perhaps the inability to integrate information from multiple sources. For example, alterations in visual perception, in particular an enhanced processing of fine detail or local structure (increased local connectivity) at the expense of a loss of the ‘larger picture’ (reduced long-range connectivity), have consistently been shown to be a feature of ASD. In addition, because the techniques used here are also routinely used in humans, our work not only has strong translational potential, but also points to a biomarker that might be used to assess the efficacy of any therapeutic intervention in both mice and men. Lastly, our work challenges a long-standing finding that connectivity changes are transient in this mouse model of FXS/ASD, since we now demonstrated these changes in adult animals.