The term periallocortex refers to one of three types of allocortex defined on the basis of cytoarchitecture. The others are paleocortex and archicortex. periallocortex is a transition zone between the proisocortex of neocortex and allocortex. It has two components: peripaleocortex and periarchicortex, which represent the transition zones of paleocortex and archicortex respectively ( Stephan-1976 ).