Features of the establishment of the spontaneous activity of neurons of the trigeminal sensory nuclei of viable sections of the rat brainstem in postnatal ontogenesis.

An attempt was made to characterize the features of the development of the neurons of the sensory trigeminal nuclei, a basic structure of the sensory support of alimentary behavior, in the late stages of postnatal ontogenesis. A technique involving viable sections of the brainstem of infant rats at the ages of two, four, and eight weeks was utilized. An increase with age in the number of neurons possessing spontaneous activity (44% at two weeks; 69% at eight weeks), an increase in the frequency of discharges, the appearance by the fourth week of a population of cells with high-frequency spontaneous activity, and an increase in the number of such neurons by the eighth week. Three types of background-active neurons were distinguished: episodic, continuous, and group; and the dynamics of the change in the ratios of these types with age was demonstrated. Significant changes with age were not found in resting potentials, although a tendency to its increase takes place between the second and eighth weeks of postnatal development.