Comparative anatomical study of ventrolateral thalamic mass in humans and monkeys.

Cytoarchitecture and enzyme activity in the ventrolateral thalamic mass of humans and monkeys were examined using conventional Nissl, myelin stain and histochemical methods. According to the data obtained from cytometric analysis, the histogram patterns of cell dimensions and cell density in each ventrolateral thalamic nucleus in humans and monkeys were very similar. Moreover, acetylcholinesterase-stained sections revealed a parcellation of the ventrolateral thalamic nuclei that could be correlated with that in the monkey thalamus. Apart from differences of size, the nuclei of the human and monkey thalamus are remarkably similar. We proposed accordingly that a new parcellation of human thalamic nuclei be based on cytometric analysis and histochemical staining.