Lesion of the ponto-geniculo-occipital pathways in kittens. I. Effects on sleep and on unitary discharge of the lateral geniculate nucleus.

Suppression of geniculate ponto-geniculo-occipital (PGO) waves was achieved in kittens by performing bilateral mesencephalic lesions of the PGO pathways. Sleep-wake parameters and the spontaneous unit activity in the lateral geniculate nucleus (LGN) were then chronically recorded during one month after the lesions. Whereas the states of vigilance remained normal, a significant reduction of the unitary discharge in the LGN during paradoxical sleep (PS) and particularly of its phasic component, was observed concomitantly with the suppression of PGO waves. It is concluded that phasic discharge of LGN neurons during PS is controlled by PGO-related mechanisms and that its suppression during the developmental period provides a model for studying its significance on brain maturation.