Le sommeil paradoxal : son contrôle par l'hypothalamus

This article aims at reviewing the latest results on the neuronal mechanisms controlling paradoxical sleep onset and maintenance. It was long believed that this behavioral state originates only from ponto-medullary structures. However, recent studies demonstrate that paradoxical sleep, still generated by pontine structures, is triggered by the hypothalamus. In our last model, the neurons containing the melanoconcentrating hormone, GABAergic in nature and localized in the posterior hypothalamus, are the main generator of paradoxical sleep. They are indeed responsible for the cessation of activity of GABAergic neurons of the ventrolateral periaqueductal grey, which inhibits paradoxical sleep during waking and slow wave sleep. This inhibition allows the glutamatergic neurons of the sublaterodorsal tegmental nucleus to be activated. These neurons are responsible for cortical activation, via thalamic projections, and for muscle atonia, via glycinergic neurons of the medullary reticular formation.