Amygdalopiriform Transition Area
abbreviation: APir
Abbreviation
APir
Species
Rat
Description of part
In the subprimate mammals, the amygdalopiriform transition area (APir) is the gray formation situated in the fundus and the lateral lip of the shallow amygdaloid or semiannular (Fig. 3F) fissure and is formed of an anterior and posterior portion. The anterior portion is narrow and is interposed between the temporal (posterior) piriform cortex laterally, and the superficial amygdala (that is, PLCo) medially. The expanded posterior APir is intercalated between the ventromedial (VMEnt) (VMEA, Krettek and Price; 28M', Haug) and ventrolateral (VLEnt) (VLEA, Krettek and Price; 28L', Haug) subdivisions of the entorhinal periallocortex and the caudolateral pole of the superficial amygdala (here the PMCo). The APir differentiates itself from the other structures which surround it by the amplitude in its molecular layer (layer 1) and the lack of a defined segregation of its superficial and deep cells. Rostrally, at the level of the anterior APir, both the superficial (2) and deep (3) layer are typically displaced towards the depth of this cortical sector. Cells in the deeper stratum are, however, larger than those in the superficial one. Laterally and caudally, the superficial stratum appears broken up in roughly spherical clusters of cells. The neuronal population of the APir is morphologically and chemically heterogeneous. It contains modified pyramids, spindle shaped cells, and polymorph cells. The APir corresponds approximately to the transition zone of Haug (1976), the most anteroventral sector of VLEA (Krettek and Price, 1977c), the VLEA transition zone and BLP transition zone (Ottersen, 1982), and the transition zone of Kosel et al. (1981).
Part type
gray matter
Nomenclature
de Olmos -1985
Endorsement
The approach used by the collator Mihail Bota is not endorsed by the author of the nomenclature.
