Structures and Functions of the Sense of Taste in the Catfish (Ictalurus natalis)Atema J.
Chemistry Department, Woods Hole Oceanographic Institution, Woods Hole, Mass.
Exclusive elimination of the sense of taste in fishes is not possible by severing ''the'' taste nerve as one can do in mammals, because their taste buds are sometimes spread over very large skin areas. For this reason the effects of taste ablation and the functions of the two specific taste systems of fishes have remained unknown.One taste system is innervated by the facial nerve (VII) subserving all the taste buds on the body skin, lips and anterior part of the mouth; the other is innervated by the vagal and glosso-pharyngeal nerves (IX and X) and contains all the taste buds on the posterior part of the mouth and gill arches. It is known that the catfish finds food by taste only, since destruction of peripheral smell does not interfere with food finding abilities; taste was found earlier to function as a true distance receptor. It also serves as a testing device controlling food intake. The interaction between the two taste systems became evident when selective ablations were performed, removing either the entire sensory area of the facial lobe or the entire sensory area of the vagal lobe in the dorsal medulla oblongata. In the former case the catfish was unable to localize food accurately and to pick it up; in the latter case the fish could not swallow the food, but had no problems in localizing or picking up the pieces. Thus, the two sensory (taste) inputs have distinct functions. The facial taste system operates in accurate localization by bilaterally steering the trunk musculature, and it also triggers the ''pick-up'' reflex (in combination with tactile inputs). The vagal taste system controls the swallowing reflex. Taste functions are essentially different from the functions of the olfactory system.
Jelle Atema, Chemistry Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543 (USA)
Number of Print Pages : 22
Brain, Behavior and Evolution
Vol. 4, No. 4, Year 1971 (Cover Date: 1971)
Journal Editor: Wilczynski W. (Atlanta, Ga.)
ISSN: 0006–8977 (Print), eISSN: 1421–9743 (Online)
For additional information: http://www.karger.com/BBE