Brodmanns

Brodmanns refers to Brodmann’s areas, a cytoarchitecturally defined map of the human cerebral cortex developed by the German neurologist Korbinian Brodmann. In his 1909 atlas, Comparative Localization of the Cerebral Cortex, he divided the cortex into 52 discrete areas (Brodmann areas, abbreviated BA) based on cellular structure and organization observed in histological sections. The borders between areas are defined by patterns of cell types, layer composition, and neuronal density. The map has remained influential, though the boundaries are approximate and can vary between individuals and across species.

Several Brodmann areas are widely associated with particular functions, though modern understanding emphasizes distributed processing. BA 17 corresponds to the primary visual cortex in the calcarine region; BA 18 and 19 are secondary visual areas. BA 41 and 42 encompass the primary auditory cortex. BA 4 is the primary motor cortex, with BA 6 involved in premotor planning. Language-related areas include BA 44 and 45 (Broca’s area) and BA 22 (Wernicke’s area). BA 39 (angular gyrus) and BA 40 (supramarginal gyrus) are involved in higher-order language and cognitive functions. BA 3, 1, and 2 constitute the primary somatosensory cortex.

Impact and limitations: Brodmann’s map remains a standard reference in neuroanatomy and neuroimaging, aiding localization in research and clinical contexts. However, functional localization is highly distributed, and boundaries vary across individuals. Modern parcellations often integrate cytoarchitecture with connectivity and functional data, and have both refined and expanded beyond the original Brodmann framework, such as through later maps by von Economo and Koskinas and contemporary multimodal atlases.