insula

Grey matter of the insular region of the neocortex constitutes the insula. In gyrencephalic animals it forms part of the insular lobe, lying in the depths of the lateral fissure where it is covered by portions of the frontal, parietal, and temporal lobes. That buried position is its defining topographic feature: unlike other cortical territories, the insula is not visible on the intact lateral surface of the hemisphere without retracting the overlying opercula, and it is reached in dissection only after those coverings are displaced. In cytoarchitectural terms it includes Brodmann areas 13 to 16. Its Latin designation is the central lobe, a name that records its position at the centre of the hemisphere rather than on any exposed surface, and it is classified as cerebral hemisphere grey matter.