Development of spontaneous neuronal activity in the caudate nucleus, globus pallidus-entopeduncular nucleus, and substantia nigra of the cat

Abstract

Spontaneous single unit activity was obtained from caudate (Cd), globus pallidus-entopeduncular nucleus (GP-Ento), and substantia nigra (SN) neurons in kittens of 1–60 days of age and adult cats. Five developmental trends were found in the spontaneous firing patterns of these neurons: (1) overall mean interspike intervals (ISIs) decreased with age; (2) the occurrence of neurons with shorter mean ISIs (< 400 ms) increased with age; (3) the occurrence of neurons with burst activity increased with age; (4) burst activity became more complex with age; and (5) the rate of burst occurrence in neurons with burst activity increased with age. Neurons within each region of the basal ganglia had characteristic patterns of spontaneous activity. Furthermore, the developmental patterns of spontaneous neuronal activity were different in each structure. The spontaneous activity of GP-Ento and SN neurons matured before the spontaneous activity of Cd neurons. Thus, spontaneous firing may mature in the output nuclei of the basal ganglia prior to its maturation in the Cd.