Nucleus Gigantocellularis`in afferent projeksiyonlarının horderadish peroksidaz yöntemiyle gösterilmesi

Abstract

studies (56,92). These results may be explained by the numoreous fibers conveyed from ventral (upper) extremeties to the cervical spinal cord due to functional importance of that region. The lumbar and the thoracolumbar curves are controlled by the reticulospinal tracts which also control the lower spine and the proximal limb. The thoracal curves may be controlled by corticospinal tracts (107). There were bilaterally labeled cells at cervical and lumbar regions. At thoracal region the labelled cells were unilaterally located. This means that sensations were unilaterally conducted at thoracal levels. The lesion of a tract which has bilateral fibers will result in partial loss of function. Whereas the lesio of a tract with unilateral fibers will result in complete loss of function. Therefore, the thoracic region lacks such compansatory mechanism. This may be due to the stability of thoracal region. May this be the causation of the increased incedence of thoracic curves? The control of the lumbar and the thoracolumbar curves, and the control of thoracal curves are thought to be via different pathways. In this study, thoracic region has a different distrubition of labeled cells compared to lumbar and cervical regions. Therefore, it may be concluded that there is a difference in the innervation of thoracal region compared to other spinal levels.muscles which are active during lordosis (58). In this study, the afferent projections of gigantocellular nucleus from spinal cord have been shown. The gel form of HRP was enjected to the right gigantocellular nucleus by stereotaxic methods. HRP is a tract tracing method used for examination of organization of the nervous system. HRP is transported in the axons and dendrites of the neurons (69 ). When HRP is reacted with its substrate, hydrogen peroxide, the labeled cells become visible (69). The densely labeled cells of right gigantocellular nucleus were observed after HRP injection.Scatterd labeled cells were observed at the contralateral gigantocellular nucleus. The dens commissural fibers existing between two gigantocellular nuclei may be a mechanism for bilateral control movements and posture requiring coordination of both sides of the body. Most densely labeled cells were observed at the cervical levels. This may be due to the short distance of HRP transport. Most of the labeled cells were contralateral at cervical levels. The labeled cells at contralateral lamina VII were more numerous compare to other levels. Additionally, labeled cells at the ipsilateral lamina VII were also observed. There were scattered labeled cells at laminae IV,V,VI,VIII and X. The labeled cells, at thoracal levels were less in number compared to cervical levels. Labeled cells were observed only at contralateral side. These labeled cells were localized at contralateral lamina ll,V,VII,VIII. The labeled cells were more numerous at lamina VII. At lumbar and sacral levels, the labeled cells were located mostly at laminae V,VI,VII,VIII and IX. There were also labeled cells at ipsilateral lamina VII. The mean value of labeled cells at cervical levels was 6. This value was 4 at both thoracal and lumbar levels. Although the spinoreticular tract is defined as ipsilaterally ascending pathway it was observed that the spinoreticular tract ascends mostly contralateral^ in this study. This was in agreement to the study of Caouch et al. (1983) (92). More numerous labeled cells at the cervical levels was in accordence with the otherstudies (56,92). These results may be explained by the numoreous fibers conveyed from ventral (upper) extremeties to the cervical spinal cord due to functional importance of that region. The lumbar and the thoracolumbar curves are controlled by the reticulospinal tracts which also control the lower spine and the proximal limb. The thoracal curves may be controlled by corticospinal tracts (107). There were bilaterally labeled cells at cervical and lumbar regions. At thoracal region the labelled cells were unilaterally located. This means that sensations were unilaterally conducted at thoracal levels. The lesion of a tract which has bilateral fibers will result in partial loss of function. Whereas the lesio of a tract with unilateral fibers will result in complete loss of function. Therefore, the thoracic region lacks such compansatory mechanism. This may be due to the stability of thoracal region. May this be the causation of the increased incedence of thoracic curves? The control of the lumbar and the thoracolumbar curves, and the control of thoracal curves are thought to be via different pathways. In this study, thoracic region has a different distrubition of labeled cells compared to lumbar and cervical regions. Therefore, it may be concluded that there is a difference in the innervation of thoracal region compared to other spinal levels.muscles which are active during lordosis (58). In this study, the afferent projections of gigantocellular nucleus from spinal cord have been shown. The gel form of HRP was enjected to the right gigantocellular nucleus by stereotaxic methods. HRP is a tract tracing method used for examination of organization of the nervous system. HRP is transported in the axons and dendrites of the neurons (69 ). When HRP is reacted with its substrate, hydrogen peroxide, the labeled cells become visible (69). The densely labeled cells of right gigantocellular nucleus were observed after HRP injection.Scatterd labeled cells were observed at the contralateral gigantocellular nucleus. The dens commissural fibers existing between two gigantocellular nuclei may be a mechanism for bilateral control movements and posture requiring coordination of both sides of the body. Most densely labeled cells were observed at the cervical levels. This may be due to the short distance of HRP transport. Most of the labeled cells were contralateral at cervical levels. The labeled cells at contralateral lamina VII were more numerous compare to other levels. Additionally, labeled cells at the ipsilateral lamina VII were also observed. There were scattered labeled cells at laminae IV,V,VI,VIII and X. The labeled cells, at thoracal levels were less in number compared to cervical levels. Labeled cells were observed only at contralateral side. These labeled cells were localized at contralateral lamina ll,V,VII,VIII. The labeled cells were more numerous at lamina VII. At lumbar and sacral levels, the labeled cells were located mostly at laminae V,VI,VII,VIII and IX. There were also labeled cells at ipsilateral lamina VII. The mean value of labeled cells at cervical levels was 6. This value was 4 at both thoracal and lumbar levels. Although the spinoreticular tract is defined as ipsilaterally ascending pathway it was observed that the spinoreticular tract ascends mostly contralateral^ in this study. This was in agreement to the study of Caouch et al. (1983) (92). More numerous labeled cells at the cervical levels was in accordence with the other

SUMMARY Scoliosis is defined as the lateral deviation of the vertebral column (4). The bipedal vvalking and upright posture of human necessiate a very fine harmony of skeleton, muscle and nerve (2). Scoliosis may develop due to an interruption in this harmony. in animals, this mechanism is undeveloped compared to humanbeings. Therefore, the experimantal models of the deformity in animals and naturally occuring animal models of scoliosis may not apply to human state (3). The etiology of the idiopathic scoliosis is unknovvn. The biochemical properties of the vertebrae and the back muscles, genetic and skeletal factors, grovvth, muscle dysfunctions, the electromyographic properties of the paraspinal muscles, central nervous system and biomechanical models are majör subjects of the researches on scolosis (3). Unfortunately, there is no generally accepted scientific theory for the causation of idiopathic scoliosis. From the time of identification of scoliosis by Mery (1706) the abnormalties of muscles, bones and discs and also bad posture have been considered as the etiologic factors (3). The mechanical changes in scoliosis are explained by pathomechanical theories. These theories include :lateral spinal curves, vertebral rotation, facet joints, saggital spinal curves, rib cage and trunk muscles (3). The role of central nervous system in scoliosis are being considered in recent studies (5,6,7,8,9,10). Recent studies revieles that the etiology of scoliosis is `multifactorial` (15). The theory developed by Burwell et al. (1990) may be summarized as ` A developmental abnormality in central nervous system which affects thoracic movements and rotator muscles of the vertebra. The asymmetric function of the trunk muscles causes change in the mechanics of vertebra via the effect of gravity. This leads to vertebral rotation during grovvth and results in scoliosis (3). The importance of central nervous system in vertebral stability has been shovvn in recent studies.The dorsal part of gigantocellular nucleus controls the axial muscles which take important role in vertebral stability (56). The lesion of gigantocellular nucleus decreases lordosis performance (11). The stimulation of it results in excitation of axial 43muscles which are active during lordosis (58). In this study, the afferent projections of gigantocellular nucleus from spinal cord have been shown. The gel form of HRP was enjected to the right gigantocellular nucleus by stereotaxic methods. HRP is a tract tracing method used for examination of organization of the nervous system. HRP is transported in the axons and dendrites of the neurons (69 ). When HRP is reacted with its substrate, hydrogen peroxide, the labeled cells become visible (69). The densely labeled cells of right gigantocellular nucleus were observed after HRP injection.Scatterd labeled cells were observed at the contralateral gigantocellular nucleus. The dens commissural fibers existing between two gigantocellular nuclei may be a mechanism for bilateral control movements and posture requiring coordination of both sides of the body. Most densely labeled cells were observed at the cervical levels. This may be due to the short distance of HRP transport. Most of the labeled cells were contralateral at cervical levels. The labeled cells at contralateral lamina VII were more numerous compare to other levels. Additionally, labeled cells at the ipsilateral lamina VII were also observed. There were scattered labeled cells at laminae IV,V,VI,VIII and X. The labeled cells, at thoracal levels were less in number compared to cervical levels. Labeled cells were observed only at contralateral side. These labeled cells were localized at contralateral lamina ll,V,VII,VIII. The labeled cells were more numerous at lamina VII. At lumbar and sacral levels, the labeled cells were located mostly at laminae V,VI,VII,VIII and IX. There were also labeled cells at ipsilateral lamina VII. The mean value of labeled cells at cervical levels was 6. This value was 4 at both thoracal and lumbar levels. Although the spinoreticular tract is defined as ipsilaterally ascending pathway it was observed that the spinoreticular tract ascends mostly contralateral^ in this study. This was in agreement to the study of Caouch et al. (1983) (92). More numerous labeled cells at the cervical levels was in accordence with the otherstudies (56,92). These results may be explained by the numoreous fibers conveyed from ventral (upper) extremeties to the cervical spinal cord due to functional importance of that region. The lumbar and the thoracolumbar curves are controlled by the reticulospinal tracts which also control the lower spine and the proximal limb. The thoracal curves may be controlled by corticospinal tracts (107). There were bilaterally labeled cells at cervical and lumbar regions. At thoracal region the labelled cells were unilaterally located. This means that sensations were unilaterally conducted at thoracal levels. The lesion of a tract which has bilateral fibers will result in partial loss of function. Whereas the lesio of a tract with unilateral fibers will result in complete loss of function. Therefore, the thoracic region lacks such compansatory mechanism. This may be due to the stability of thoracal region. May this be the causation of the increased incedence of thoracic curves? The control of the lumbar and the thoracolumbar curves, and the control of thoracal curves are thought to be via different pathways. In this study, thoracic region has a different distrubition of labeled cells compared to lumbar and cervical regions. Therefore, it may be concluded that there is a difference in the innervation of thoracal region compared to other spinal levels.