A neuroanatomical study of the connectivity of the pretectal lentiform nucleus of the mesencephalon in chicken.
Item
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Title
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A neuroanatomical study of the connectivity of the pretectal lentiform nucleus of the mesencephalon in chicken.
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Identifier
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AAI9000675
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identifier
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9000675
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Creator
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Bodnarenko, Stefan Roman.
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Contributor
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Advisers: Olivia McKenna | H. P. Ziegler
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Date
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1989
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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 | Psychology, Psychobiology
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Abstract
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The LM is a nucleus in the avian brain thought to receive retinal slip signals which are relayed to oculomotor pathways to generate horizontal optokinetic nystagmus (OKN). The LM in birds is considered homologous to the nucleus of the optic tract (NOT) in mammals on the basis of its similar position within the pretectum and its common derivation from the tectal plate.;The objectives of this study were to identify the boundaries of the LM within the chicken pretectum and to describe the organization of the afferent and efferent connectivity of this area with the HRP and the tritiated amino acid tract tracing techniques.;The LM, which consists of two portions, the magnocellular and the parvicellular, was found medial to the optic tectum (OT) and lateral to the superficial synencephalic nucleus. The sources of afferent projections were identified as the contralateral retina, the ipsilateral accessory hyperstriatum (HA), nucleus of the basal optic root (nBOR), and OT. Both the retinal and the HA projections were topographically organized. In addition, the terminal innervation pattern of the HA projection within the LM was found to be similar in both hatchling and older chickens.;The efferent projections of the LM terminated in ipsilateral thalamic areas including the ventrolateral geniculate nucleus, the magnocellular dorsolateral nucleus of the anterior thalamus, the lateral dorsolateral nucleus of the anterior thalamus, the intercalated nucleus of the thalamus, in ipsilateral pretectal targets including the pretectal area, the pretectal nucleus, and the principal precommissural nucleus, in mesencephalic targets including the ipsilateral OT, nucleus Darkschewitsch, the nBOR bilaterally, the ipsilateral ventral nucleus of the deep mesencephalon, papillioform nucleus, the contralateral lateral reticular formation, in brainstem targets including the ipsilateral lateral pontine, medial pontine, and inferior olivary nucleus and bilaterally in the cerebellum. The results of retograde tracing experiments from several efferent targets suggested a differential projection from LM neurons to these targets.;The results of this study reveal the organization of the afferent and efferent pathways of the LM and provide connectivity evidence in support of the notion that the LM in birds is homologous to the NOT in mammals.
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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.
