The long-term objective of this project is a thorough understanding of the behavioral and neural mechanisms of sound localization. Previous studies of sound localization have chiefly centered on two areas: human and animal psychophysical work has established the important cues for localization while animal physiological work has shown the neural mechanisms by which the auditory system encodes these cues. This application is an effort to link these two approaches by combining animal psychophysics with physiology. This application proposes to extend our present behavioral preparation for testing sound localization in casts by freeing the head of the cat so that it can orient to the sound with unrestrained head and/or eye movements. In addition we will continue our physiological studies of sound localization by recording from cells during this behavior. There are two general specific aims: one directed to behavior and the other to physiology.
Specific aim I will develop the head-free preparation by monitoring eye, head and ear movement using the search coil technique and standard operant conditioning. We will compare the accuracy of localization in the head-fixed and head-free conditions, study the effect spectral cues on localization by narrowband pass filtering noise stimuli, and examine the role of pinna muscles by studying the movements of the pinna as well as the effect on localization ability of paralyzing the pinna muscles.
Specific aim II is aimed at physiological recordings in these animals while they are actively localizing sounds. We will continue our examination of the motor error hypothesis by recording in the superior colliculus and studying the effect of eye position on auditory responses. Then we propose to move to the auditory cortex where we expect to find cells whose response properties are correlated with the behavioral localization of the stimulus. By progressively narrowband pass filtering the noise stimulus, we expect he cat to gradually mislocalize the sound. At some point the cat will be near threshold, looking half the time at the proper location and the other half to some phantom location. At this point we can deliver the identical stimulus with two different behaviors and correlate the neural activity to one behavior or another. Spatial hearing and sound localization are important basic functions of the auditory system: defects in binaural function in human patients can lead to considerable difficulty in detecting signals embedded in noise, such as understanding conversations in a crowded room, which is perhaps the most common complaint of the hearing-impaired and can lead to severe social withdrawal.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
5R01DC002840-07
Application #
6516149
Study Section
Special Emphasis Panel (ZRG1-IFCN-6 (01))
Program Officer
Luethke, Lynn E
Project Start
1996-03-01
Project End
2006-02-28
Budget Start
2002-03-01
Budget End
2003-02-28
Support Year
7
Fiscal Year
2002
Total Cost
$198,608
Indirect Cost
Name
University of Wisconsin Madison
Department
Physiology
Type
Schools of Medicine
DUNS #
161202122
City
Madison
State
WI
Country
United States
Zip Code
53715
Gai, Yan; Ruhland, Janet L; Yin, Tom C T et al. (2013) Behavioral and modeling studies of sound localization in cats: effects of stimulus level and duration. J Neurophysiol 110:607-20
Tollin, Daniel J; Ruhland, Janet L; Yin, Tom C T (2013) The role of spectral composition of sounds on the localization of sound sources by cats. J Neurophysiol 109:1658-68
Ruhland, Janet L; Yin, Tom C T; Tollin, Daniel J (2013) Gaze shifts to auditory and visual stimuli in cats. J Assoc Res Otolaryngol 14:731-55
Tollin, Daniel J; McClaine, Elizabeth M; Yin, Tom C T (2010) Short-latency, goal-directed movements of the pinnae to sounds that produce auditory spatial illusions. J Neurophysiol 103:446-57
Dent, Micheal L; Tollin, Daniel J; Yin, Tom C T (2009) Influence of sound source location on the behavior and physiology of the precedence effect in cats. J Neurophysiol 102:724-34
Tollin, Daniel J; Ruhland, Janet L; Yin, Tom C T (2009) The vestibulo-auricular reflex. J Neurophysiol 101:1258-66
Moore, Jordan M; Tollin, Daniel J; Yin, Tom C T (2008) Can measures of sound localization acuity be related to the precision of absolute location estimates? Hear Res 238:94-109
Tollin, Daniel J; Koka, Kanthaiah; Tsai, Jeffrey J (2008) Interaural level difference discrimination thresholds for single neurons in the lateral superior olive. J Neurosci 28:4848-60
Joris, Philip; Yin, Tom C T (2007) A matter of time: internal delays in binaural processing. Trends Neurosci 30:70-8
Tollin, Daniel J; Yin, Tom C T (2005) Interaural phase and level difference sensitivity in low-frequency neurons in the lateral superior olive. J Neurosci 25:10648-57

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