This research is directed at providing an ultrastructural description of functional circuits in the cat's lateral geniculate nucleus, particularly in the A-laminae. This will enable us to better understand the means by which geniculate circuitry achieves its main function, which is to control the flow of information from retina to cortex. That is, the vast majority (80-90%) of synaptic input onto geniculate relay cells that is nonretinal serves to gate or control the gain of retinogeniculate transmission. There are many different ways in which this can be achieved, and it seems likely that these represent the neural substrates for many (but not all) forms of visual attention. Our main technique will continue to be electron microscopic reconstruction of single cells and/or axons labeled either with intracellular iontophoresis of horseradish peroxidase or with extracellular application of phaseolus vulgaris leucoagglutinin. We wish to obtain a complete description of the patterns and sources of synaptic inputs to relay X and Y cells plus interneurons. We shall focus on reliable differences seen among cell types, which also requires a description of the variability seen among cell classes. We ultimately want to understand the relationship between retinal and nonretinal inputs formed onto relay cells in order to better understand how the nonretinal inputs might affect retinogeniculate transmission. Nonretinal sources of input that will be investigated include: local collaterals of relay cell axons; interneurons; the perigeniculate nucleus; the visual cortex; and the brainstem reticular formation, including the parabrachial region, the locus coeruleus, and the raphe nucleus. Immunocytochemistry will be used in an attempt to reveal the putative transmitters used by certain synaptic inputs, such as: gamma-aminobutyric acid by interneurons and perigeniculate cells; acetylcholine, noradrenalin, and serotonin by brainstem axons; and glutamate (or a related substance) by retinal and cortical axons. We also hope to develop immunocytochemical techniques to identify the postsynaptic receptors, such as GABAA vs. GABAB, NMDA vs. non- NMDA, and muscarinic vs. nicotinic. Finally, we shall develop an in vitro preparation to label elements not easily labeled in vivo. This includes the GABAergic interneurons and perigeniculate cells plus various neuron pairs that might be synaptically connected.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
2R01EY003604-09
Application #
3257974
Study Section
Visual Sciences B Study Section (VISB)
Project Start
1981-05-01
Project End
1994-04-30
Budget Start
1989-05-01
Budget End
1990-04-30
Support Year
9
Fiscal Year
1989
Total Cost
Indirect Cost
Name
State University New York Stony Brook
Department
Type
Schools of Arts and Sciences
DUNS #
804878247
City
Stony Brook
State
NY
Country
United States
Zip Code
11794
Godwin, D W; Van Horn, S C; Eriir, A et al. (1996) Ultrastructural localization suggests that retinal and cortical inputs access different metabotropic glutamate receptors in the lateral geniculate nucleus. J Neurosci 16:8181-92
Tamamaki, N; Uhlrich, D J; Sherman, S M (1995) Morphology of physiologically identified retinal X and Y axons in the cat's thalamus and midbrain as revealed by intraaxonal injection of biocytin. J Comp Neurol 354:583-607
Gunluk, A E; Bickford, M E; Sherman, S M (1994) Rearing with monocular lid suture induces abnormal NADPH-diaphorase staining in the lateral geniculate nucleus of cats. J Comp Neurol 350:215-28
Bickford, M E; Gunluk, A E; Van Horn, S C et al. (1994) GABAergic projection from the basal forebrain to the visual sector of the thalamic reticular nucleus in the cat. J Comp Neurol 348:481-510
Cucchiaro, J B; Uhlrich, D J; Sherman, S M (1993) Ultrastructure of synapses from the pretectum in the A-laminae of the cat's lateral geniculate nucleus. J Comp Neurol 334:618-30
Bickford, M E; Gunluk, A E; Guido, W et al. (1993) Evidence that cholinergic axons from the parabrachial region of the brainstem are the exclusive source of nitric oxide in the lateral geniculate nucleus of the cat. J Comp Neurol 334:410-30
Cucchiaro, J B; Uhlrich, D J; Sherman, S M (1991) Electron-microscopic analysis of synaptic input from the perigeniculate nucleus to the A-laminae of the lateral geniculate nucleus in cats. J Comp Neurol 310:316-36
Cucchiaro, J B (1991) Early development of the retinal line of decussation in normal and albino ferrets. J Comp Neurol 312:193-206
Cucchiaro, J B; Bickford, M E; Sherman, S M (1991) A GABAergic projection from the pretectum to the dorsal lateral geniculate nucleus in the cat. Neuroscience 41:213-26
Uhlrich, D J; Cucchiaro, J B; Humphrey, A L et al. (1991) Morphology and axonal projection patterns of individual neurons in the cat perigeniculate nucleus. J Neurophysiol 65:1528-41

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