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How do owls localize interaurally phase-ambiguous signals?

Saberi, Kourosh and Farahbod, Haleh and Konishi, Masakazu (1998) How do owls localize interaurally phase-ambiguous signals? Proceedings of the National Academy of Sciences of the United States of America, 95 (11). pp. 6465-6468. ISSN 0027-8424. http://resolver.caltech.edu/CaltechAUTHORS:SABpnas98

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Abstract

Owls and other animals, including humans, use the difference in arrival time of sounds between the ears to determine the direction of a sound source in the horizontal plane. When an interaural time difference (ITD) is conveyed by a narrowband signal such as a tone, human beings may fail to derive the direction represented by that PTD. This is because they cannot distinguish the true ITD contained in the signal from its phase equivalents that are ITD +/- nT, where T is the period of the stimulus tone and n is an integer. This uncertainty is called phase-ambiguity. All ITD sensitive neurons in birds and mammals respond to an ITD and its phase equivalents when the ITD is contained in narrowband signals. It is not known, however, if these animals show phase-ambiguity in the localization of narrowband signals. The present work shows that barn owls (Tyto alba) experience phase-ambiguity in the localization of tones delivered by earphones. We used sound-induced head-turning responses to measure the sound-source directions perceived by two owls. In both owls, head-turning angles varied as a sinusoidal function of ITD. One owl always pointed to the direction represented by the smaller of the two ITDs, whereas a second owl always chose the direction represented by the larger ITD (i.e., ITD-T).


Item Type:Article
Additional Information:Copyright © 1998 by the National Academy of Sciences. Contributed by Masakazu Konishi, March 24, 1998. We thank Kip Keller and Jamie Mazer for commenting on an earlier draft of the paper. This work was supported by National Institutes of Health Grants DC03648–01 and DC00134–19A1. The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.
Subject Keywords:INFERIOR COLLICULUS; CROSS-CORRELATION; TIME DIFFERENCES; BARN OWL; SENSITIVITY; STIMULI; MODEL
Record Number:CaltechAUTHORS:SABpnas98
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:SABpnas98
Alternative URL:http://www.pnas.org/cgi/content/abstract/95/11/6465
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:1558
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:30 Jan 2006
Last Modified:26 Dec 2012 08:44

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