Structure of the piriform cortex of the adult rat. A Golgi study.

The piriform cortex (PC) was studied in the adult rat with anilines, rapid Golgi and Golgi-Colonnier techniques. As in other animals in the PC of the adult rat three layers can be distinguished: layer I or plexiform layer, layer II or superficial cellular layer and layer III or deep cellular layer. Golgi impregnations allowed to describe seven different types of cells. Pyramidal cells, in which it is possible to distinguish three subtypes (superficial, middle and deep pyramidal cells) by virtue of their morphology and location. Bipolar cells, a very little and scarce type of cell restricted to layer I and that has not been previously described. Fusiform cells, similar to those found in other species. Semilunar cells, also like those described in other animals but which are only found in the posterior PC. These cells resemble other type of cell, the ovoid cells that neither have been described in other animals and, on the contrary, are only located in the anterior PC. Stellate cells, which are a very wide population of cells with variable sizes, dendritic patterns and locations. Horizontal cells, similar to pyramidal cells but oriented in horizontal direction and polymorphic cells, whose the most striking feature is their smooth and beaded prolongations. Morphological features of these cells are compared with those described in the cells of the PC of other animals.