The term insular region originally referred to a cytoarchitecturally defined portion of the cerebral cortex that occupies all of the insula and immediately adjacent portions of surrounding frontal lobe and temporal lobe ( Brodmann-1909 ). Subsequently it has come to refer to one of three components of the olfactocentric division of the paralimbic regions( Mesulam-1984 ). The other components are the orbitofrontal region and the temporopolar region. The three regions surround and radiate from the piriform cortex ( allocortex ) into the corresponding insula, orbital gyri and polar portion of the superior temporal gyrus. Each is subdivided into an agranular ( periallocortex ) belt, a dysgranular ( proisocortex ) belt and a granular ( true isocortex ) belt, which is continous with granular areas of surrounding neocortex: the primary somatosensory cortex, the secondary somatosensory cortex and the retroinsular area. The corresponding subdivisions of the insular region are the agranular insula, the dysgranular insula, and the granular insula ( Mesulam-1984 ).