The term middle occipital gyrus refers to the major convolution on the lateral surface of the occipital lobe in the human. Identified by dissection, it is separated from the superior occipital gyrus dorsally by the intra-occipital sulcus, from the inferior occipital gyrus ventrally by the inferior occipital sulcus, and from the parietal lobe and temporal lobe rostrally by a topologically ill-defined boundary approximated by an oblique plane connecting the parieto-occipital sulcus dorsally with the preoccipital notch ventrally ( Ono-1990 ). It has no topological equivalent in the macaque or in the smooth cerebral cortex of the rat or mouse ( NeuroNames ).