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Author (up) Heffner, H.E.; Heffner, R.S.
Title The hearing ability of horses Type Journal Article
Year 1983 Publication Equine Pract Abbreviated Journal
Volume 5 Issue Pages 27-32
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Notes Cited By (since 1996): 2; Export Date: 21 October 2008 Approved no
Call Number Equine Behaviour @ team @ Serial 4520
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Author (up) Heffner, R.S.; Heffner, H.E.
Title Localization of tones by horses: use of binaural cues and the role of the superior olivary complex Type Journal Article
Year 1986 Publication Behavioral Neuroscience Abbreviated Journal Behav Neurosci
Volume 100 Issue 1 Pages 93-103
Keywords Animals; Auditory Pathways/physiology; Auditory Perception/*physiology; Avoidance Learning/physiology; Brain Mapping; Electroshock; Female; Horses/*physiology; Male; Olivary Nucleus/anatomy & histology/*physiology; Orientation/physiology; Pitch Perception/physiology; Sound Localization/*physiology
Abstract The ability of horses to use binaural time and intensity difference cues to localize sound was assessed in free-field localization tests by using pure tones. The animals were required to discriminate the locus of a single tone pip ranging in frequency from 250 Hz to 25 kHz emitted by loudspeakers located 30 degrees to the left and right of the animals' midline (60 degrees total separation). Three animals were tested with a two-choice procedure; 2 additional animals were tested with a conditioned avoidance procedure. All 5 animals were able to localize 250 Hz, 500 Hz, and 1 kHz but were completely unable to localize 2 kHz and above. Because the frequency of ambiguity for the binaural phase cue delta phi for horses in this test was calculated to be 1.5 kHz, these results indicate that horses can use binaural time differences in the form of delta phi but are unable to use binaural intensity differences. This finding was supported by an unconditioned orientation test involving 4 additional horses, which showed that horses correctly orient to a 500-Hz tone pip but not to an 8-kHz tone pip. Analysis of the superior olivary complex, the brain stem nucleus at which binaural interactions first take place, reveals that the lateral superior olive (LSO) is relatively small in the horse and lacks the laminar arrangement of bipolar cells characteristic of the LSO of most mammals that can use binaural delta I.
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Language English Summary Language Original Title
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ISSN 0735-7044 ISBN Medium
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Notes PMID:3954885 Approved no
Call Number Equine Behaviour @ team @ Serial 5634
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Author (up) Heffner, R.S.; Heffner, H.E.
Title Hearing in large mammals: Horses (Equus caballus) and cattle (Bos taurus) Type Journal Article
Year 1983 Publication Behavioral Neuroscience Abbreviated Journal
Volume 97 Issue 2 Pages 299-309
Keywords auditory range & sensitivity, horses vs cattle
Abstract Determined behavioral audiograms for 3 horses and 2 cows. Horses' hearing ranged from 55 Hz to 33.3 kHz, with a region of best sensitivity from 1 to 16 kHz. Cattle hearing ranged from 23 Hz to 35 kHz, with a well-defined point of best sensitivity at 8 kHz. Of the 2 species, cattle proved to have more acute hearing, with a lowest threshold of –21 db (re 20 μN/m–2) compared with the horses' lowest threshold of 7 db. Comparative analysis of the hearing abilities of these 2 species with those of other mammals provides further support for the relation between interaural distance and high-frequency hearing and between high- and low-frequency hearing. (39 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
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Publisher American Psychological Association Place of Publication Us Editor
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ISSN 1939-0084(Electronic);0735-7044(Print) ISBN Medium
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Notes Approved no
Call Number Equine Behaviour @ team @ 1983-29540-001 Serial 5633
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