The hypoglossal nucleus of the primate: a Golgi study.

The neurons of the hypoglossal nucleus were examined in Golgi preparations of adult macaque and squirrel monkeys. Two distinct types of neurons were found. The first type was a large multipolar cell which was typical of the majority of the neurons of the nucleus. Its soma ranged in size from 18 to 50 micrometers and numerous dendrites emerged from it. The dendritic spread of these neurons was within the ipsilateral nucleus, across the midline into the contralateral hypoglossal nucleus, or out into the adjacent reticular formation. The second type of neuron was a small cell. The soma of this neuron was oval in shape, measured less than 20 micrometers in its largest diameter, and gave off only two or three dendrites which remained within the nucleus.