We propose to study the connections of the cat primary auditory cortex (AI) with the inferior colliculus, medial geniculate body, and contralateral auditory cortex. Using anterograde transport methods to label terminal axonal fields and horseradish peroxidase to mark somata, the terminal zones and types of neurons contributing to these pathways will be defined. Particular types of morphologically characterized neurons can be assigned to particular functional roles, e.g., corticollicular, corticothalamic, or commissural. The goal is to clarify the anatomical relations of the midbrain, diencephalic, and telencephalic parts of the auditory system. This has important implications for cerebral localization and restitution of function, praticularly with regard to the auditory consequences of head injury, aging, or infectious agents. The sensory substrates for monaural and binaural phenomena, frequency analysis, and of speech must involve each of these pathways. Since connectional, structural, and neurochemical evidence suggests that not all parts of this pathway have the same role, this proposal concentrates on the primary pathway between thye central nucleus of the inferior colliculus, the ventral nucleus of the medial geniculate body, and AI, and the reciprocal circuits often interconnecting them. We will define the cells of origin, their topographical projections, and their covergence or divergence. Our results have implications for sreial and hierarchical models of information processing. Mixtures of tracers will be injected into physiologically defined areas in the auditory midbrain, thalamus, or cortex. A study in the rat will examine the inferior colliculus neurons projecting to the ipsilateral medial geniculate body or to the contralateral inferior colliculus, and the distribution of their axon terminals. We shall also study the auditory cortical neurons accumulating the putative inhibitory neurotransmitter, gamma-aminobutyric acid, and glutamic acid decarbosylase. Finally, the structure of layers V and VI neurons will be analyzed. These connectional, transmitter-specific, and structural inquiries form a more secure basis for interspecific comparisons with regard to neural homology, and for deriving the circuits of auditory neorcortes. These observations will provide a framework for comparing the organization of AI with the primary somatic sensory and visual cortices.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
2R01NS016832-06
Application #
3397168
Study Section
Hearing Research Study Section (HAR)
Project Start
1980-12-01
Project End
1988-11-30
Budget Start
1985-12-01
Budget End
1986-11-30
Support Year
6
Fiscal Year
1986
Total Cost
Indirect Cost
Name
University of California Berkeley
Department
Type
Schools of Arts and Sciences
DUNS #
094878337
City
Berkeley
State
CA
Country
United States
Zip Code
94704
Winer, J A; Wenstrup, J J; Larue, D T (1992) Patterns of GABAergic immunoreactivity define subdivisions of the mustached bat's medial geniculate body. J Comp Neurol 319:172-90
Matsuoka, M; Nagawa, F; Okazaki, K et al. (1991) Detection of somatic DNA recombination in the transgenic mouse brain. Science 254:81-6
Winer, J A; Larue, D T (1989) Populations of GABAergic neurons and axons in layer I of rat auditory cortex. Neuroscience 33:499-515
Winer, J A; Larue, D T (1988) Anatomy of glutamic acid decarboxylase immunoreactive neurons and axons in the rat medial geniculate body. J Comp Neurol 278:47-68
Winer, J A; Morest, D K; Diamond, I T (1988) A cytoarchitectonic atlas of the medial geniculate body of the opossum, Didelphys virginiana, with a comment on the posterior intralaminar nuclei of the thalamus. J Comp Neurol 274:422-48
Games, K D; Winer, J A (1988) Layer V in rat auditory cortex: projections to the inferior colliculus and contralateral cortex. Hear Res 34:1-25
Winer, J A; Larue, D T (1987) Patterns of reciprocity in auditory thalamocortical and corticothalamic connections: study with horseradish peroxidase and autoradiographic methods in the rat medial geniculate body. J Comp Neurol 257:282-315
Winguth, S D; Winer, J A (1986) Corticocortical connections of cat primary auditory cortex (AI): laminar organization and identification of supragranular neurons projecting to area AII. J Comp Neurol 248:36-56
Code, R A; Winer, J A (1986) Columnar organization and reciprocity of commissural connections in cat primary auditory cortex (AI). Hear Res 23:205-22
Winer, J A (1986) Neurons accumulating [3H]gamma-aminobutyric acid (GABA) in supragranular layers of cat primary auditory cortex (AI) Neuroscience 19:771-93

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