摘要:

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.

ISSN:0006-8977    

DOI:10.1159/000125438

出版商:S. Karger AG    

年代:1971

数据来源: Karger

摘要:

In frogs (Rana temporaria) the evoked potentials and the neuronal responses to stimulation of the optic nerve have been found in the lateral geniculate, posterocentral, posterolateral and posterior thalamic nuclei of the contralateral side. Responses to stimulation of the sciatic nerve have beenfound bilaterally in the posterior thalamic, posterocentral and posterolateral nuclei. In the primordium hippocampi bilateral responses have been registered after the stimulation of the optic and sciatic nerves and a number of diencephalic structures. Bilateral destruction of lateral geniculate, posterocentral, posterolateral and posterior thalamic nuclei abolished the visual responses in the primordium hippocampi. Somatic responses in the primordium hippocampi disappeared after bilateral lesions of the posterior thalamic nucleus and of the caudal parts of posterocentral and posterolateral nuclei. These areas are considered as relay nuclei of visual and somatic telencephalic pathways.In frogs (Rana ridibunda) unilateral lesions of the caudal part of the dorsal thalamus were made. In sections stained according to Fink and Heimer and with the modified Bielshowsky-Viktorov methods, the terminal degeneration was found in the primordium hippocampi of both hemispheres.

ISSN:0006-8977    

DOI:10.1159/000125439

出版商:S. Karger AG    

年代:1971

数据来源: Karger

ISSN:0006-8977    

DOI:10.1159/000125440

出版商:S. Karger AG    

年代:1971

数据来源: Karger

摘要:

The predatory strikes of a sidewinder rattlesnake (Crotalus cerastes) can be avoided by kangaroo rats (Dipodomys merriami) in the normal condition and also after either of two surgical manipulations: (1) removal of the eyes, or (2) reduction of middle ear volume. When both these operations are performed, however, the kangaroo rat is struck by the rattlesnake with relative ease.Reduction of middle ear volume alone in a natural population of kangaroo rats resulted in a high loss of animals with reduced middle ear volume; most of them disappeared from the population during the dark phase of the moon. It is concluded that both vision and audition play significant adaptive roles in predator avoidance.

ISSN:0006-8977    

DOI:10.1159/000125441

出版商:S. Karger AG    

年代:1971

数据来源: Karger

摘要:

Eye and ear reactions due to posturalchanges, optokinetic, rotatory and postrotatory stimulation have been investigated in 15 rabbits. The animals were restrained but unanaesthetised. Optokinetic, rotatory and post-rotatory stimulation resulted in an eye and ear nystagmus.Both functions were found to be strictly coupled and not separable by narcotics. Recording from single motor units allowed differentiation between tonically and phasically innervated units of the ear muscles. Direction-specific units were found in posture changing experiments.

ISSN:0006-8977    

DOI:10.1159/000125442

出版商:S. Karger AG    

年代:1971

数据来源: Karger

ISSN:0006-8977    

DOI:10.1159/000125443

出版商:S. Karger AG    

年代:1971

数据来源: Karger