E Brodmann Areas

A Brodmann area is a region of the cerebral cortex, in the human or other primate brain, defined by its cytoarchitecture, or histological structure and organization of cells.

Brodmann areas were originally defined and numbered by the German anatomist Korbinian Brodmann based on the cytoarchitectural organization of neurons he observed in the cerebral cortex using the Nissl method of cell staining. Brodmann published his maps of cortical areas in humans, monkeys, and other species in 1909, along with many other findings and observations regarding the general cell types and laminar organization of the mammalian cortex.

Brodmann areas have been discussed, debated, refined, and renamed exhaustively for nearly a century and remain the most widely known and frequently cited cytoarchitectural organization of the human cortex.

Many of the areas Brodmann defined based solely on their neuronal organization have since been correlated closely to diverse cortical functions. For example, Brodmann areas 3, 1 and 2 are the primary somatosensory cortex; area 4 is the primary motor cortex; area 17 is the primary visual cortex; and areas 41 and 42 correspond closely to primary auditory cortex. Higher order functions of the association cortical areas are also consistently localized to the same Brodmann areas by neurophysiological, functional imaging, and other methods (e.g., the consistent localization of Broca’s speech and language area to the left Brodmann areas 44 and 45). However, functional imaging can only identify the approximate localization of brain activations in terms of Brodmann areas since their actual boundaries in any individual brain requires its histological examination.

Areas 1, 2 and 3 – Primary somatosensory cortex in the postcentral gyrus (frequently referred to as Areas 3, 1, 2 by convention)
Area 4– Primary motor cortex
Area 5 – Superior parietal lobule
Area 6 – Premotor cortex and Supplementary Motor Cortex (Secondary Motor Cortex) (Supplementary motor area)
Area 7 – Visuo-Motor Coordination
Area 8 – Includes Frontal eye fields
Area 9 – Dorsolateral prefrontal cortex
Area 10 – Anterior prefrontal cortex (most rostral part of superior and middle frontal gyri)
Area 11 – Orbitofrontal area (orbital and rectus gyri, plus part of the rostral part of the superior frontal gyrus)
Area 12 – Orbitofrontal area (used to be part of BA11, refers to the area between the superior frontal gyrus and the inferior rostral sulcus)
Area 13 and Area 14 – Insular cortex
Area 15 – Anterior Temporal lobe
Area 16 – Insular cortex
Area 17 – Primary visual cortex (V1)
Area 18 – Secondary visual cortex (V2)
Area 19 – Associative visual cortex (V3, V4, V5)
Area 20 – Inferior temporal gyrus
Area 21 – Middle temporal gyrus
Area 22 – Part of the superior temporal gyrus, included in Wernicke’s area
Area 23 – Ventral posterior cingulate cortex
Area 24 – Ventral anterior cingulate cortex.
Area 25 – Subgenual area (part of the Ventromedial prefrontal cortex)
Area 26 – Ectosplenial portion of the retrosplenial region of the cerebral cortex
Area 27 – Piriform cortex
Area 28 – Ventral entorhinal cortex
Area 29 – Retrosplenial cortex
Area 30 – Subdivision of retrosplenial cortex
Area 31 – Dorsal Posterior cingulate cortex
Area 32 – Dorsal anterior cingulate cortex
Area 33 – Part of anterior cingulate cortex
Area 34 – Dorsal entorhinal cortex (on the Parahippocampal gyrus)
Area 35 – Part of the perirhinal cortex (in the rhinal sulcus)
Area 36 – Part of the perirhinal cortex (in the rhinal sulcus)
Area 37 – Fusiform gyrus
Area 38 – Temporopolar area (most rostral part of the superior and middle temporal gyri)
Area 39 – Angular gyrus, considered by some to be part of Wernicke’s area
Area 40 – Supramarginal gyrus considered by some to be part of Wernicke’s area
Areas 41 and 42 – Auditory cortex
Area 43 – Primary gustatory cortex
Areas 44 and 45 – Broca’s area, includes the opercular part and triangular part of the inferior frontal gyrus
Area 46 – Dorsolateral prefrontal cortex
Area 47 – Orbital part of inferior frontal gyrus
Area 48 – Retrosubicular area (a small part of the medial surface of the temporal lobe)
Area 49 – Parasubicular area in a rodent
Area 52 – Parainsular area (at the junction of the temporal lobe and the insula)