The goal of this research is to study the neural mechanisms underlying binaural signal processing in the cat inferior colliculus. The proposal addresses three issues: 1) the mechanism by which high frequency neurons utilize interaural time cues; 2) the relationship between synaptic organization and binaural processing; and 3) the role of descending cortical inputs on binaural response properties. The high frequency studies may provide the neural basis for the observation that human listeners can lateralize complex high frequency signals on the basis of interaural time cues; a finding that has necessitated modification of the classic view that the low and high frequency system use separate localization cues: interaural time and interaural intesity cues, respectively. The purpose of the synaptic organization studies is to determine the neural mechanisms responsible for binaural interactions, and the related ultrastructural components. The rationale of examining cortical influences is the finding that afferents from the ipsilateral auditory cortex project to a specific and division substantial subdivision of the inferior colliculus, viz. the dorsal cortex. Since descending cortical and ascending lemniscal inputs are mixed in this subdivision, the binaural interactions may be different from that in the central nucleus; a division of the inferior colliculus that only receives lemniscal input. To resolve the above issues, we will employ extra and intracellular recordings, acoustical and electrical stimulation, and light and electron microscopic analysis.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS018027-06
Application #
3398051
Study Section
Hearing Research Study Section (HAR)
Project Start
1981-12-01
Project End
1988-06-30
Budget Start
1986-12-01
Budget End
1988-06-30
Support Year
6
Fiscal Year
1987
Total Cost
Indirect Cost
Name
University of Connecticut
Department
Type
School of Medicine & Dentistry
DUNS #
City
Farmington
State
CT
Country
United States
Zip Code
06030
Kuwada, S; Batra, R (1999) Coding of sound envelopes by inhibitory rebound in neurons of the superior olivary complex in the unanesthetized rabbit. J Neurosci 19:2273-87
Kuwada, S; Batra, R; Yin, T C et al. (1997) Intracellular recordings in response to monaural and binaural stimulation of neurons in the inferior colliculus of the cat. J Neurosci 17:7565-81
Oliver, D L; Beckius, G E; Shneiderman, A (1995) Axonal projections from the lateral and medial superior olive to the inferior colliculus of the cat: a study using electron microscopic autoradiography. J Comp Neurol 360:17-32
Fitzpatrick, D C; Kuwada, S; Batra, R et al. (1995) Neural responses to simple simulated echoes in the auditory brain stem of the unanesthetized rabbit. J Neurophysiol 74:2469-86
Feng, J J; Kuwada, S; Ostapoff, E M et al. (1994) A physiological and structural study of neuron types in the cochlear nucleus. I. Intracellular responses to acoustic stimulation and current injection. J Comp Neurol 346:1-18
Batra, R; Kuwada, S; Stanford, T R (1993) High-frequency neurons in the inferior colliculus that are sensitive to interaural delays of amplitude-modulated tones: evidence for dual binaural influences. J Neurophysiol 70:64-80
Stanford, T R; Kuwada, S; Batra, R (1992) A comparison of the interaural time sensitivity of neurons in the inferior colliculus and thalamus of the unanesthetized rabbit. J Neurosci 12:3200-16
Oliver, D L; Kuwada, S; Yin, T C et al. (1991) Dendritic and axonal morphology of HRP-injected neurons in the inferior colliculus of the cat. J Comp Neurol 303:75-100
Batra, R; Barlow Jr, R B (1990) Efferent control of temporal response properties of the Limulus lateral eye. J Gen Physiol 95:229-44
Batra, R; Kuwada, S; Stanford, T R (1989) Temporal coding of envelopes and their interaural delays in the inferior colliculus of the unanesthetized rabbit. J Neurophysiol 61:257-68

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