Cytoarchitectonic Variations of "Barrels" Organized in the Primary Somatosensory Cortex of Some Species of the Muroidea (Superfamily)

Abstract

In 18 species of the Muroidea, the cytoarchitecture of the barrel structures of the posteromedial barrel subfield (PMBSF) in the primary somatosensory cortex was studied comparatively by cresyl violet staining.
All species examined revealed barrel structures. The barrel patterns were classified into three types, A, B and C, on the basis of the features of the "side", "septum" and "hollow" of each barrel. The type A barrel was the most clearly defined, the type C barrel was obscure in appearance, and the type B barrel was intermediate between types A and C. In general, the larger the brain, the less obvious were the barrels. However, Meriones unguiculatus had a type A barrel even though its brain was large. This situation is discussed in relation to the peculiar habitat, such as arid desert.