Publication: ALTERATIONS OF CORTICAL CONNECTIVITY IN A MOUSE MODEL OF PREMATURE BRAIN INJURY

Published in:

Authors: Salma Ellouze, Amel Amara, Géraldine Meyer-Dilhet, Julien Courchet, Olivier Raineteau

Summary

Cortical circuits are built at perinatal times and gradually refined in an activity- dependent manner during the postnatal period of critical plasticity. Although lesions of the CNS occurring during this period recover better than those occurring later in life, they are often associated with long-term cognitive deficits, which suggests that neuronal circuits rewiring, in particular within the cortex, may either be incomplete or inappropriate. Here we used chronic hypoxia, a mouse model of very premature birth, to study the long-term impact of premature brain injuries on glutamatergic neuron’s maturation and cortical circuit’s formation. Our results reveal gradual and profound alterations of glutamatergic neurons dendritic arborizations following chronic hypoxia, that differentially affect their apical and basal dendritic compartments. Using retrograde tracing, we show that these dendritic alterations are paralleled by a global cortical hyperconnectivity as well as a redistribution of long-distance cortical connections. Finally, testing of sociability reveals an impairment for social novelty in young adult hypoxic mice, which amplifies in adulthood. Altogether, our results highlight how premature brain injuries, such as those resulting from very premature births, impact cortical neuron maturation and connectivity, as well as associated behaviors.

Link to HAL – hal-04991366