Neurons of origin of the perforant path

Neurons of origin of the perforant path were labeled in entorhinal cortex after exposure of their injured axons to horseradish peroxidase. Almost all neurons in layer II of portions of the entorhinal cortex ipsilateral to the injury site contained diffuse and/or granular label. They included stellates, pyramids, fusiforms, and two cell types whose dendrites arose from two or three characteristic sites and divided into branches which were largely parallel or oblique to the pial surface. These two types predominated in the area lateralis, and stellates with dendrites mainly oriented perpendicular to the pia were the most numerous cells in the area medialis.