Nomenclature

Abstract

A review of the nomenclature for cortical areas in the rat reveals a confusing variety of terms and terminological systems. Brodmann’s (1909) nomenclature is designed mainly for primates. Although Brodmann personally used this numerical system to describe many nonprimate species, including rodents, the system seems to be inadequate for such use, because problems of comparative anatomy and functional equivalence between primates and rodents are unresolved. One shortcoming is evident insofar as Brodmann (1909) incorrectly identified the auditory cortex in rodents. He presented a peculiar areal pattern in the temporal region. Krieg (1946, 1947) revised and expanded Brodmann’s nomenclature for use with rats. A second, more biologically relevant problem arises from the implied comparability between the cortical areas of primates and rodents when the same areal terms are used to describe both. In most cases this problem of homology of cortical areas is unresolved. Many other systems of nomenclature have been designed for special studies, but these are not generally applicable outside the specialized fields for which they were designed.