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. Author manuscript; available in PMC: 2013 Nov 26.
Published in final edited form as: Ann N Y Acad Sci. 2011 Apr;1225:10.1111/j.1749-6632.2011.05981.x. doi: 10.1111/j.1749-6632.2011.05981.x

Figure 1.

Figure 1

The proposed organization of the neocortex of an early mammal based on a cladistic analysis of the cortex of extant mammals and proportions of neocortex reflected in the endocasts of the skulls of early mammals. Neocortex was small relative to olfactory (piriform) cortex together with the olfactory bulb. Areas of neocortex included primary somatosensory area S1 flanked by rostral (RS) and caudal (CS) somatosensory fields and a second somatosensory area, S2. A taste or gustatory area (g) may have been present. Auditory cortex (Aud) included one (A1) or two primary areas and possibly secondary areas. Visual cortex included a primary area (V1), a secondary area (V2), a temporal visual field (T), and prostriata. Frontal cortex included orbital frontal (OF) and medial frontal (MF) areas but no motor cortex. Cortex of the medial wall of the cerebral hemisphere included granular (RSg) and agranular (RSa) areas, and at least dorsal (CCd) and ventral (CCv) divisions of cingulate cortex. For reference, the superior colliculus (SC) and the inferior colliculus (IC) of the midbrain are shown