A quantitative study of cochlear afferent axons in birds

Koppl, C and Wegscheider, A and Gleich, O and Manley, GA (2000) A quantitative study of cochlear afferent axons in birds. HEARING RESEARCH, 139 (1-2). pp. 123-143. ISSN 0378-5955, 1878-5891

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Abstract

This paper is a comparative study of auditory-nerve morphology in birds. The chicken (Gallus gallus), the emu (Dromaius novaehollandiae) and the starling (Sturnus vulgaris) were chosen as unspecialised birds that have already been used in auditory research The data are discussed in comparison to a similar earlier study on the barn owl: a bird with highly specialised hearing, in an attempt to separate general avian patterns from species specialisations. Average numbers of afferent fibres from 8775 (starling) to 12406 (chicken) were counted, excluding fibres to the lagenar macula. The number of fibres representing different frequency ranges showed broad maxima in the chicken and emu, corresponding to hearing ranges of best sensitivity and/or particular behavioural relevance. Mean axon diameters were around 2 mu m in the chicken and starling and around 3 mu m in the emu. Virtually all auditory afferents were myelinated. The mean thickness of the myelin sheaths was between 0.33 mu m (starling) and 0.4 mu m (emu). There was a consistent pattern in the diameters of axons deriving from different regions. Axons from very basal, i.e. highest-frequency, parts of the basilar papilla were always the smallest. In the emu and the chicken, axons from the middle papillar regions were, in addition, larger than axons innervating apical regions, (C) 2000 Elsevier Science B.V, All rights reserved.

Item Type: Article
Uncontrolled Keywords: STARLING STURNUS-VULGARIS; AUDITORY-NERVE FIBERS; OWL TYTO-ALBA; EMU DROMAIUS-NOVAEHOLLANDIAE; PIGEON BASILAR PAPILLA; HAIR CELL REGENERATION; BARN OWL; NUCLEUS MAGNOCELLULARIS; FREQUENCY REPRESENTATION; SOUND LOCALIZATION; auditory; basilar papilla; eighth nerve; barn owl; chicken; myelination
Subjects: 500 Science > 590 Zoological sciences
Divisions: Medicine > Lehrstuhl für Hals-Nasen-Ohren-Heilkunde
Depositing User: Dr. Gernot Deinzer
Date Deposited: 17 May 2021 14:53
Last Modified: 17 May 2021 14:53
URI: https://pred.uni-regensburg.de/id/eprint/42956

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