The goal is to understand the cellular basis for central processing in specific binaural and monaural circuits of cell types, extending from the cochlear nucleus to the inferior colliculus. either directly or via the nuclei of the superior olive and lateral lemniscus. An interdisciplinary approach will characterize the structural, electrophysiological, and neurochemical properties of these circuits, especially the inhibitory components. The synaptic connections of the cell types will be studied anatomically, while their response properties to acoustic stimulation will be defined physiologically and the related groups of neurons labeled with micromarkers through the recording electrodes. Cytochemical labeling will localize the suspected transmitters in the afferent inputs to these cell types. The contributions of these inputs to the generation of the neuronal responses will be studied by stimulating or blocking them neurochemically in combined anatomical and physiological experiments. The analysis will help to form useful models of the synaptic mechanisms underlying the response properties of each type of neuron in the circuit. This is necessary to explain the cellular mechanisms governing the operation of these circuits in normal perception and their alterations in response to trauma. The reaction of the mature cochlear nucleus to acoustic trauma, as evinced in sensorineural hearing loss due to noise damage of the cochlea, will be assessed in terms of the new growth of axons and the neurochemistry of the transmitters, which may involve inhibitory synapses. Finally the binaural responses of neurons in the inferior colliculus will be analyzed physiologically with acoustic stimuli that are known to elicit the precedence effect. The hypothesis is that the neural events underlying the binaural perceptual effect depend on inhibitory mechanisms in hearing.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Program Projects (P01)
Project #
5P01DC001366-05
Application #
2014456
Study Section
Special Emphasis Panel (SRC (04))
Project Start
1992-12-01
Project End
1999-11-30
Budget Start
1996-12-01
Budget End
1999-11-30
Support Year
5
Fiscal Year
1997
Total Cost
Indirect Cost
Name
University of Connecticut
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
City
Farmington
State
CT
Country
United States
Zip Code
06030
Batra, Ranjan (2006) Responses of neurons in the ventral nucleus of the lateral lemniscus to sinusoidally amplitude modulated tones. J Neurophysiol 96:2388-98
Kuwada, Shigeyuki; Fitzpatrick, Douglas C; Batra, Ranjan et al. (2006) Sensitivity to interaural time differences in the dorsal nucleus of the lateral lemniscus of the unanesthetized rabbit: comparison with other structures. J Neurophysiol 95:1309-22
Kim, J J; Gross, J; Potashner, S J et al. (2004) Fine structure of degeneration in the cochlear nucleus of the chinchilla after acoustic overstimulation. J Neurosci Res 77:798-816
Kim, J J; Gross, J; Potashner, S J et al. (2004) Fine structure of long-term changes in the cochlear nucleus after acoustic overstimulation: chronic degeneration and new growth of synaptic endings. J Neurosci Res 77:817-28
Muly, S M; Gross, J S; Potashner, S J (2004) Noise trauma alters D-[3H]aspartate release and AMPA binding in chinchilla cochlear nucleus. J Neurosci Res 75:585-96
Kim, J J; Gross, J; Morest, D K et al. (2004) Quantitative study of degeneration and new growth of axons and synaptic endings in the chinchilla cochlear nucleus after acoustic overstimulation. J Neurosci Res 77:829-42
Sterbing, Susanne J; Hartung, Klaus; Hoffmann, Klaus-Peter (2003) Spatial tuning to virtual sounds in the inferior colliculus of the guinea pig. J Neurophysiol 90:2648-59
Batra, Ranjan; Fitzpatrick, Douglas C (2002) Processing of interaural temporal disparities in the medial division of the ventral nucleus of the lateral lemniscus. J Neurophysiol 88:666-75
Smith, Lee; Gross, Julia; Morest, D Kent (2002) Fibroblast growth factors (FGFs) in the cochlear nucleus of the adult mouse following acoustic overstimulation. Hear Res 169:1-12
Sterbing, Susanne J; Hartung, Klaus; Hoffmann, Klaus-Peter (2002) Representation of sound source direction in the superior colliculus of the guinea pig in a virtual auditory environment. Exp Brain Res 142:570-7

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