Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
PHYSIOLOGY OF SINGLE PUTATIVE COCHLEAR EFFERENTS IN THE CHICKEN
Autore:
KAISER A; MANLEY GA;
Indirizzi:
TECH UNIV MUNICH,INST ZOOL,LICHTENBERGSTR 4 D-85747 GARCHING GERMANY
Titolo Testata:
Journal of neurophysiology
fascicolo: 6, volume: 72, anno: 1994,
pagine: 2966 - 2979
SICI:
0022-3077(1994)72:6<2966:POSPCE>2.0.ZU;2-R
Fonte:
ISI
Lingua:
ENG
Soggetto:
AUDITORY-NERVE FIBERS; CROSSED OLIVOCOCHLEAR BUNDLE; GUINEA-PIG COCHLEA; MIDDLE-EAR MUSCLE; HAIR-CELLS; ELECTRICAL-STIMULATION; GALLUS-DOMESTICUS; BASILAR PAPILLA; RESPONSE PROPERTIES; VESTIBULAR NEURONS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Physical, Chemical & Earth Sciences
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
80
Recensione:
Indirizzi per estratti:
Citazione:
A. Kaiser e G.A. Manley, "PHYSIOLOGY OF SINGLE PUTATIVE COCHLEAR EFFERENTS IN THE CHICKEN", Journal of neurophysiology, 72(6), 1994, pp. 2966-2979

Abstract

1. An experimental approach was developed that allowed recording of neurophysiological activity from single putative cochlear efferents in the auditory brain stem of anesthetized chickens with the use of glassmicropipettes. The aim of this study was to study spontaneous and tone-evoked activity from single efferent neurons in the chick and to compare their properties with those of other vertebrate hair cell organs. Because the birds, like mammals, have a complex hearing organ with different hair cell types and different afferent and efferent innervation, the purpose of this study was also to determine whether different types of efferents exist. 2. In the same electrode penetrations, putative trapezoid fibers were also isolated. In addition, the penetration angle permitted recordings from units in both cochlear nuclei, nucleus magnocellularis and nucleus angularis (probably mostly cochlear afferents), in the same animal. This allowed monitoring of the auditory sensitivity of the individual animal during the experiment. With the use of physiological criteria, it was possible to distinguish between trapezoid fibers and putative cochlear efferents. Possible alternative origins of the responses described are discussed. 3. Tuning curve characteristics of putative efferents were determined. They were as sensitive as ascending auditory neurons. Q(10dB) values of efferent tuning curves were <2.5 and thus showed poorer frequency selectivity than ascending fibers; in some cases they covered the entire hearing range of the chicken. 4. Latencies to tone pips were different for ascending neuronsand putative efferent units. For trapezoid fibers and neurons from the cochlear nuclei, latencies usually did not exceed 5 ms, whereas latencies of efferents were always longer. 5. Because of the interaural canal that connects both middle ear cavities in birds, the measurement of the lateralization of the efferents was difficult. In any case, the majority of putative cochlear efferents responded more sensitively to sound stimulation of the contralateral side. 6. Of the efferent units,28% showed no spontaneous activity. The others either showed regular spontaneous activity, or their time-interval histograms showed longer modes than ascending fibers. In general, mean spontaneous activity waslower than in ascending fibers, being <30 spikes/s. 7. In contrast toreports from mammalian studies, in which efferents only showed one peristimulus time (PST) response pattern to tonal stimuli (chopper), twodifferent response types were found in this study; two excitation types (chopper and primarylike) and one suppression type. Although the first resembles the activity of outer hair cell efferents in mammals, the latter has not been described so far and may have a different function in the efferent control of hearing.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 05/12/20 alle ore 01:34:08