[Electrophysiologic study of the functional characteristics of cortical input into the hippocampus of newborn...

Functional maturation of perforant pathway synapses on neurones of the dorsal hippocampus and fascia dentata was examined in unanaesthetized rabbits 1 to 25 days of age, by means of extracellular recording of fiold potentials and of neuronal responses to electrical stimulation of the cortical afferent input. In the areas CA1 and CA3 of the dorsal hippocampus, field potentials, activating and inhibitory neuronal responses to stimulation of the perforant pathway with single impulses were recorded from the first day of the postnatal life, while short-latency responses of the fascia dentata were revealed later--at the end of the first week or the beginning of the second week of life. The data obtained suggest that in rabbits, the synapses of the perforant pathway are functioning from the first days after birth. The postnatal development of the cortical afferent input to the hippocampus is related to the maturation of the dentate gyrus.