Many disorders are born in utero including Autism and many neurodevelopmental disorders. to understand hos they are generated and whether and how brain structures are impacted already in utero, it is instrumental to develop quantitative atlases of brain structures. IN this aim, we used the recently developed transparization (I disco) technique that enable to dissolve fatty acids rendering the brain transparent. Using selective markers of cholinergic and catecholaminergic neurons, we constructed an automated atlas with all these neurons counted for each structure. We performed this analysis from early in utero development to postnatal periods. The results are quite spectacular, with a semi logarithmic growth of the number of immune-positive neurons in each structure and a quantification of all neurons allowing a comparison between structures. Importantly and in keeping with our earlier studies we discovered important changes in some structures during delivery and birth validating our suggestion of the importance of alterations occurring during this highly vulnerable period. This world première will be very useful to identify quantitatively changes occurring in utero and during birth in autism and other developmental disorders. This mouse atlas can be used to validate hypothesis suggested in humans, see our earlier report (the pelagros project) on Brain Perimeter changes in utero in future babies that will or not be diagnosed with autism (caly et al 2021) and our similar early observations on neuronal growth in animal model of autism (cloarec et al 2020). The paper in press in Neuroimage provides all the data of this Atlas.
studying in parallel human and mouse brains will allow to better understand the inaugurating pathogenic events taking place during development
