The term anterior insula refers to the more rostral of two parts of the human insula defined on the basis of topology. It consists of five convolutions: three short insular gyri, the accessory insular gyrus and the transverse insular gyrus. It is larger than the more caudal part, the long insular gyri (also known as 'posterior insula'), from which it is separated by the oblique central insular sulcus ( Ture-1999 ). Some authors describe a sixth convolution, the precentral gyrus of the insula, as locted between the the short insular gyri and the central insular sulcus ( Roberts-1970 ). The defining feature of the anterior insula, the central insular sulcus, is found in the baboon but not the macaque ( Mufson-1997 ); and the anterior insula has no topological equivalent in the rat or the mouse ( NeuroNames ).