ELECTROPHYSIOLOGICAL CHARACTERISTICS OF OPTIC NERVE INPUT TO LATERAL ACCESSORY OPTIC NUCLEUS AND OTHER SUBCORTICAL STRUCTURES.
Item
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Title
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ELECTROPHYSIOLOGICAL CHARACTERISTICS OF OPTIC NERVE INPUT TO LATERAL ACCESSORY OPTIC NUCLEUS AND OTHER SUBCORTICAL STRUCTURES.
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Identifier
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AAI8203313
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identifier
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8203313
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Creator
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PASSIKOFF, DAVID.
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Contributor
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Prof. William S. Battersby
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Date
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1981
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Language
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English
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Publisher
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City University of New York.
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Subject
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Psychology, Physiological
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Abstract
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The main purpose of the present study was to investigate the nature of the functional fiber group(s) of the optic nerve (ON) which innervate(s) the lateral accessory optic nucleus (LAON) and to compare this with that of those that innervate the other subcortical visual structures. Emphasis was placed on conduction velocity. Secondarily, the present study sought to explore the question of which subcortical visual structures send fibers to, and/or receive fibers from, the LAON. Finally, the present study attempted to determine, electrophysiologically, if centrifugal fibers coursing through the ON exist in the cat, and if so, to locate their source, with special attention to the LAON. To accomplish these purposes, cats were acutely prepared with stimulating/recording electrodes in the ON, LAON, dorsal and ventral layers of the lateral geniculate nucleus (LGN), superior colliclus (SC), pretectum (PRT), pulvinar (PUL) and mesencephalic reticular formation (MRF). The LAON was found to receive two functional groups of ON fibers, conducting at 61 and 9 m/sec. Layers A and Al of the LGN also receive two such groups, conducting at 35 and 19 m/sec, as does layer B of the LGN, conducting at 30 and 9 m/sec. The SC receives one such group, conducting at 32 m/sec. Evidence was obtained which indicated that the PRT receives two such groups, conducting at 36 and 24 m/sec, and that the PUL receives at least one such group, conducting at 43 m/sec. The MRF receives no direct ON input. The LAON was found to send fibers to, and receive fibers from, all the above structures, based on functional considerations. Most, if not all of these projections are monosynaptic. Both the LAON and an area about 2 mm below the SC, just lateral to the central gray, were found to send centrifugal projections back into the ON. But, in both cases, there is at least one intervening synapse. On the basis of similarity in response characteristics, this synapse may be the same for both structures, representing some as yet unknown structure which sends a direct centrifugal projection back into the ON. The results were discussed with regard to the uniqueness of the LAON within the mammalian visual system, the W, X, Y classification of retinal ganglion cells and ON axons, and the relation of the neurophysiology of the mammalian visual system to the behavioral response of the animal to its visual world.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
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Program
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Psychology
