The term nucleus Pul of Olszewski refers to the pulvinar as defined on the basis of cyto-myeloarchitecture in the rhesus macaque ( Olszewski-1952 ). It consists of four subdivisions, the inferior pulvinar nucleus, lateral pulvinar nucleus, medial pulvinar nucleus and anterior pulvinar nucleus. The internal architecture of the pulvinar "shows considerable uniformity", thus it is subdivided on a topographical basis. "The basic element... is a lightly-stained cell, medium-sized, multipolar, and plump."