The morphology of the striatum (St, caudoputamen complex) and globus pallidus (GP) was studied by stereological methods in representatives of four mammalian orders (Insectivora, Rodentia, Lagomorpha, Carnivora). The aim of our study was to give the first detailed morphometric characteristics of the St and GP in the animals. The paraffin-embedded brain tissue blocks were cut in the coronal plane into 50 μm sections, which were stained for Nissl substance. The morphometric analysis of the St and GP has included such parameters as the volume, numerical density, and total number of neurons. The increase in the volume of the St and GP was accompanied by an increase in the total number of neurons and a decrease in their numerical density. The percentage contribution of the GP volume in the corpus striatum shows progressive traits in the common shrew and fox.
