Distribution of optic fibers in the cat

Abstract

This study undertook to investigate pathways and connections of optic tract fibers in the pulvinar, hypothalamus, ventral lateral geniculate, pretectal region and superior colliculus.Thirty-five adult cats were utilized -28 experimental subjects and seven controls. The right eye was removed and the cats allowed to survive for periods from three to 61 days. The chief method of investigation was the silver impregnation technique of Nauta-Gygax ('54), supplemented by Marchi and luxol-blue cresyl-fastviolet methods.Study of fiber patterns of degeneration in serial sections of the Nauta-Gygax preparations revealed no prcterminal axonal degeneration in the hypothalamus or pulvinar. Portions of a completely crossed accessory optic tract as described by Hayhow ('59) were identified. Preterminal degeneration of fine collaterals of the larger optic fibers was found in the dorsal one-third of the lateral portion of the ventral lateral geniculate. Large areas of preterminal degeneration and many fibers of passage were observed in the pretectal region. Localized areas of preterminal degeneration in this region were interpreted as belonging to the pretectal nucleus and to the nucleus of the optic tract. A large number of fine optic fibers was found terminating in the superficial stratum opticum of the superior colliculus. Two areas of preterminal degeneration lateral to the colliculus were interpreted as extension of the pretectal nucleus and as the nucleus olivaris colliculi.

Autoradiographic Study of the Retinal Projections in the Chinese Pangolin, <i>Manis pentadactyla</i>

“…This system is totally contra lateral in many mammals, such as cats, hedgehogs, tree shrews, and red belly squirrels [Meikle and Sprague, 1964;Singleton and Peele, 1965;Campbell et al, 1967;Wu and Shen. 1988], but is partly bilateral in Formosan monkeys [Chen et al, 1987], This system has not been found in echo-locating bats, although it exists in nonecho-locating bats [Simpson, 1984, for review].…”

“…Although studies of a number of mammals have shown a common pattern of retinal projections to several subcortical areas, the suprachiasmatic nucleus (SCN), dorsal and ventral lateral geniculate nuclei (dLGN and vLGN), pretectal complex (PRT), supe rior colliculus (SC), pulvinar nucleus, and the ac cessory optic system [Meikle and Sprague, 1964;Singleton and Peele, 1965;Campbell et al, 1967;Glickstein, 1967;Campbell, 1969;Cummings and De Lahunta, 1969;Lund et al, 1974;Takahashi, et al, 1977;Rodieck, 1979;Simpson, 1984;Cooper, 1986;Chen et al, 1987;Cooper and Magnin, 1987], the vis ual system of pangolins has not been examined. The aim of this study, therefore, was to gain data on the visual system in this group by investigating the retinal projections of Chinese pangolins (Manis pentadac tyla) by autoradiography.…”

The Organization of the Thalamo-Cortical Visual Pathways in the Cat; pp. 256–272

“…Since the PN does not receive a direct input from the optic tract [2,25,37,44,59], the topographical organisation of its visual field representation must be impressed upon it by the nucleus of origin of its afferent fibres. Both neuroanatomical [2,56,66] and physiological [8,10,67] methods have demonstrated a significant input from the dorsal lateral geniculate nucle us to the PN, but without distinguishing between the MIN and the lami nated component of the LGNd as the possible source of the input; only Barris et al [4] have obtained negative results with respect to an intrathalamic connection between LGNd and PN.…”

Parallels in the Visual Afferent Projections of the Thalamus in the Hedgehog <i>(Paraechinus hypomelas) </i>and the Turtle <i>(Pseudemys scripta</i><i>)</i>

“…It is thus important that the pattern of retinal projections to the dorsal and ventral lateral geniculate nuclei we have described for the hedgehog is similar to that described in another species of hedgehog [Campbell, J ane and Y ashon, 1967] as well as to those described in a large number of other mammals including the opossum [Bodian, 1937;G iolli. 1965], phalanger [Packer, 1942;H aymow, 1967], rat [H ayhow , Sefton and Webb, 1962], cat [H ayhow, 1958;Singleton and Peele, 1965;L aties and Sprague, 1969], squirrel [A planalp, 1968; T igges, 1969], tree shrew [T igges, 1966;C ampbell, J ane and Yashon, 1967;A planalp, 1968], rabbit [G iolli and G u thrie, 1969], and monkey [Jones, 1966;Campos-O rtega and G lees, 1967], Although reptiles have been less in tensively studied, the retinal pattern described here for Pseudemys scripla is similar to those described in other species of turtle [Knapp and Kang, 1968 a, b]. These pathways are also similar to those described for the pi geon [Karten and R evzin, 1966].…”