Anatomical connections and electrophysiological properties of toral and dorsal tegmental neurons in the terrestrial urodele Salamandra salamandra

• Published in: Journal fur Hirnforschung Vol. 31; no. 1; p. 65
• Main Authors: Manteuffel, G, Naujoks-Manteuffel, C
• Format: Journal Article
• Language: English
• Published: Germany 1990
• Subjects: Action Potentials; Animals; Auditory Pathways - anatomy & histology; Auditory Pathways - physiology; Horseradish Peroxidase; Neural Pathways - anatomy & histology; Neural Pathways - physiology; Semicircular Canals - anatomy & histology; Semicircular Canals - physiology; Sense Organs - anatomy & histology; Sense Organs - physiology; Tegmentum Mesencephali - anatomy & histology; Tegmentum Mesencephali - physiology; Urodela - anatomy & histology; Urodela - physiology; Vestibule, Labyrinth - anatomy & histology; Vestibule, Labyrinth - physiology
• ISSN: 0021-8359

Fire salamanders (Salamandra salamandra) are strictly terrestrial urodele amphibians, having lost electroreception and the lateral line system during metamorphosis. The present study demonstrates that (i) the lateral lemniscus is supplied by fibers of the medullary acoustic nucleus (nucleus intermedius) and the superior olive; (ii) the subtectal dorsal tegmentum can be clearly separated into a dorsally located torus semicircularis and a ventrally situated dorsal tegmental nucleus, the former processing auditory and vibratory, the latter vestibular signals; and (iii) the hearing capabilities of this animal, as estimated from the tuning of toral units, are comparable to those of anurans with extratympanic sound transmission. It is concluded that vibration sensitivity and hearing are involved in defensive reactions in the non-vocalizing fire salamander. The vestibular cells in the dorsal tegmentum probably relay a head-velocity input to the optic tectum, thus providing a self-motion signal for the visual localization center.