Studies On the Somatotopy of the Trigeminal System in the Mallard, Anas Platyrhynchos L.: I. the Ganglion Trigeminale

Abstract

The trigeminal ganglion of the mallard can be divided into an ophthalmic and a maxillo-mandibular portion. The cell areas of the two portions can be distinguished after injection of the respective trigeminal branches with the enzyme horseradish peroxidase (HRP). Most maxillary cells are found in the dorsal part of the maxillo- mandibular portion of the ganglion, most mandibular cells in the ventral part. There is, however, a large intermediate area, where the two cell groups intermingle. It is possible to distinguish dark-type and light-type ganglion cells in normal material stained with the Klüver-Barrera method. This classification does not concur with the distinction of ophthalmic and maxillo-mandibular cells. In our experiments the labeling of cells was found after much longer survival times than reported generally in the literature. This long time may depend on a latency period before the damaged axon can take up HRP, as well as on a low rate of transport in the peripheral trigeminal system of the mallard.