The term opercular part of the inferior frontal gyrus (IFGop) refers to one of three parts of the frontal operculum (OPR) of the inferior frontal gyrus (IFG), which overlies the insula (INS).. Its boundary with the INS is the superior limiting sulcus (sls) ( Ture-1999 ). Identified by dissection, it is the rostral part. The others are the triangular part of the inferior frontal gyrus (IFGtr) and the opercular part of the inferior frontal gyrus (IFGop). It is found in the human ( Carpenter-1983 ), but not in the macaque ( Martin-2000 Paxinos-2009a ) where the OPRfr includes part of the precentral gyrus (PRG) as well as IFG and the two are not identified separately.. It is not found in the smooth cerebral cortex (CTX) of the rat or mouse ( NeuroNames ). Updated 30 Aug 2024.