The development of the lateral spinothalamic tract in rats and its response to lesion.
Item
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Title
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The development of the lateral spinothalamic tract in rats and its response to lesion.
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Identifier
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AAI9405560
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identifier
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9405560
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Creator
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Miya, Dorene Yone.
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Contributor
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Adviser: Gordon A. Barr
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Date
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1993
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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 aim of these experiments was to examine the maturation of the ascending lateral spinothalamic tract (LSTT) in fetal, neonatal and young rats and to examine the LSTT response to lesion relative to its development. In experiment 1, WGA-HRP and green fluorescent microspheres were injected into the lateral ventrobasal nucleus of the thalamus in rats on fetal day 18 or 19, the day of birth and postnatal day 10. The results show that the LSTT projects to the ventrobasal thalamus by the earliest day examined, fetal day 18. WGA-HRP and microspheres both labeled cells contralateral to the injection in the ventromedial dorsal horn and superficial lamina of the lumbar spinal cord in all age groups examined. Postnatal animals also showed labeling in the neck of the dorsal horn. In fetal animals only, WGA-HRP faintly labeled a tract in the contralateral lateral funiculus of the dorsal horn. At this age, faint labeling was also seen in the ipsilateral medial lemniscus and most lateral portion of the contralateral principal sensory trigeminal nucleus.;Di-I was used as a postfixation anterograde tract tracer in experiment 2 and showed that the LSTT had developed at least to the level of the cervical spinal cord by fetal day 17, the earliest age examined.;Experiment 3 examined the anatomical and behavioral consequence of lesions that are made to the spinal cord at different developmental stages of the LSTT. Two age groups of animals (fetal day 17 and postnatal day 12 or 14) underwent a lateral hemisection of the thoracic spinal cord. Both groups of animals underwent behavioral testing approximately 72 hours after surgery and again at postnatal day 47. At the end of the survival period, all animals were injected with WGA-HRP into the ventrobasal thalamus. Morphologically, both groups showed major dorsal horn disorganization caudal to and at the site of lesion. Behaviorally, both groups were also similar in their severe impairment in responding to noxious tests and no major differences were noted. Replication with WGA-HRP is necessary to make conclusions as to the plasticity of the LSTT in developing animals.
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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.
