The area acustico-vestibularis of Discoglossus pictus. II. The primary afferent projections.
In the present report the primary projections to the dorsal rhombencephalic alar plate (area acustico-vestibularis, AAV) of the adult anuran amphibian Discoglossus pictus have been studied by means of the anterograde transport of horseradish peroxidase (HRP). As in Alytes cisternasii, other member of the family Discoglossidae, no primary afferent fibers to the AAV were found from nerves other than the VIIIth cranial nerve. No remanent of the lateral line system in the adult stage is present. The projections of the dorsal root of nerve VIIIth distribute over the dorsal nucleus and rostrally reach the aspect of the cerebellum. Caudally projects to the large cells of the ventral nucleus and terminate caudally, in the dorsolateral neuropil, at levels coincident with the IX motor nucleus. The projection of the ventral root also reaches the cerebellum in its lateral aspect but also fibers to the nucleus cerebelli were observed. The extensive projection to the ventral nucleus is also continued caudally to the caudal nucleus and ends around the solitary tract. Main terminal fields were located in two neuropils, one subventricular and other in an intermediate position. In addition, from both nerve branches, fibers leave the AAV and reach the reticular formation. Particularly, fibers from the posterior branch enter the superior olivary nucleus. Retrograde labeled neurons in the vicinity of the VII motor nucleus are interpreted as efferent cells to the labyrinth.
Gonzalez
A
A
Departamento de Morfología Microscópica, Facultad de Biología, Universidad Complutense, Madrid, Spain.
Muñoz
M
M
D000818:Animals; D001001:Anura / Q000033:anatomy & histology*; D001306:Auditory Pathways / Q000033:anatomy & histology; D001931:Brain Mapping; D007758:Ear, Inner / Q000294:innervation; D006735:Horseradish Peroxidase; D012249:Rhombencephalon / Q000033:anatomy & histology*; D014722:Vestibule, Labyrinth / Q000033:anatomy & histology / Q000294:innervation*; D000159:Vestibulocochlear Nerve / Q000033:anatomy & histology*
D006735:Horseradish Peroxidase