Entopeduncular nucleus of the cat: A Golgi study

Abstract

The entopeduncular nucleus of the cat was studied by the rapid Golgi method. Large and medium-size, spiny neurons were recognized. The large neurons, the main constituents of the nucleus, had stellate or piriform cell bodies with a mean diameter of 24 × 53 μm, and three to six primary dendrites. The medium-size neurons were mainly seen in the ventromedial portions of the nucleus. They had fusiform or polygonal cell bodies, which measured an average 18 × 29 μm and emitted three to five primary dendrites. The axons of the entopeduncular neurons ran usually ventromedially or caudally, and rarely dorsomedially and rostrally. Some axons emitted intranuclear axon collaterals. No intrinsic, short-axon neurons were found. Many fibers were traced from the internal capsule to the nucleus. These fibers gave many terminal collaterals to the entopeduncular nucleus and appeared to run further beyond its boundaries. Some afferent fibers to the nucleus were also traced from the ansa lenticularis and gave terminal collaterals to the nucleus, which were distributed mainly in its ventrolateral portions.