The term basal operculum refers to the part of the inferiorr frontal gyrus (IFG) that most directly overlies the anterior insula (INSa) in the human ( Mai-1997 ). Identified by dissection, it is separated from the INS by the ventral part ofTthe anterior limiting sulcus (alms) ( Ture-1999 ). It is not found in macaques, where the INSa is continuous with the orbital gyri (ORG) ( Mesulam-1984 ), nor in the smooth cerebral cortex (CTX) of rodents ( NeuroNames ). Updated 28 Aug 2024.