Summary
The distribution, dendritic trees and axonal courses of spinally projecting cells in the dorsal column nuclei were studied after labelling by retrograde HRP transport. The region of densest distribution was at the base of the two nuclei and in the area between them, extending for about 2 mm caudally from the obex. Only very few cells were found inside the cell cluster regions of the nuclei, where their dendrites had a free stellate form. The great majority, lying between, deep, or rostral to the cluster regions, also had a stellate form, except where they impinged on the boundaries of the cluster regions or on other nuclear borders; the spread of dendrites was dramatically restricted at such boundaries, often leading to a fusiform appearance in transverse sections which however was not evident in the parasagittal plane. No justification was therefore found for subdividing the population on morphological grounds. Axons of these cells descended ipsilaterally in either the medial part of the dorsolateral fascicle or in the adjacent lateral part of the cuneate fascicle, at cervical levels, and probably in about equal numbers. Most axons destined for the DLF followed a deep caudolateral trajectory, while many destined for the DC had a more dorsal or lateral course. Collateral branches were seen within the nuclei but could not be followed far. The fact that few if any cells lying in the region of maximum distribution of the spinally projecting cells were labelled following injections of HRP into the thalamic ventroposterior nucleus emphasizes that they form a distinctive entity within this medullary nuclear complex, and that any axon branches they give into the contralateral brainstem must have some other destination than the VPL. Two other groups of neurons were labelled by HRP implants into the dorsal columns — one in the ventrolateral medullary reticular formation, and the other in the nucleus of the solitary tract.
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References
Andersen P, Brooks CMcC, Eccles JC, Sears TA (1964) The ventro-basal nucleus of the thalamus: potential fields, synaptic transmission and excitability of both presynaptic and postsynaptic components. J Physiol (Lond) 174: 348–369
Armstrong R, Blesovsky L, Corsiglia R, Gordon G (1979) Descending projections from the cat's dorsal column nuclei. J Physiol (Lond) 296: 43P
Basbaum AI, Fields H (1979) The origin of descending pathways in the dorsolateral funiculus of the spinal cord of the cat and rat; further studies on the anatomy of pain modulation. J Comp Neurol 187: 513–532
Berkley KJ (1975) Different targets of different neurons in nucleus gracilis of the cat. J Comp Neurol 163: 285–304
Berkley KJ, Hand PJ (1978) Efferent projections of the gracile nucleus in the cat. Brain Res 153: 263–283
Blomqvist A, Flink R, Bowsher D, Griph S, Westman J (1978) Tectal and thalamic projections of dorsal column and lateral cervical nuclei: a quantitative study in the cat. Brain Res 141: 335–341
Blomqvist A (1980) Gracilo-diencephalic relay cells: a quantitative study in the cat using retrograde transport of horseradish peroxidase. J Comp Neurol 193: 1097–1125
Boivie J (1971) The termination in the thalamus and zona incerta of fibres from the dorsal column nuclei in the cat. An experimental study with silver impregnation methods. Brain Res 28: 459–490
Brodal A (1957) The reticular formation of the brain stem. Anatomical aspects and functional correlations. Oliver and Boyd, Edinburgh
Brodal A (1981) Neurological anatomy in relation to clinical medicine (3rd edn.) Oxford University Press, New York Oxford
Bromberg MB, Burnham JA, Towe AL (1981) Doubly projecting neurones of the dorsal column nuclei. Neurosci Lett 25: 215–220
Brown AG (1981) Organization in the spinal cord. The anatomy and physiology of identified neurones. Springer, Berlin Heidelberg New York
Brown AG, Brown PB, Fyffe REW, Pubols LM (1983) Receptive field organization and response properties of spinal neurones with axons ascending the dorsal columns in the cat. J Physiol (Lond) 337: 575–588
Brown AG, Fyffe REW (1981) Form and function of neurones with axons ascending the dorsal columns in cat. J Physiol (Lond) 321: 31–47
Brown AG, Gordon G, Kay RH (1974) A study of single axons in the cat's medial lemmiscus. J Physiol (Lond) 236: 225–246
Bull MS, Berkley KJ (1983) Differences in the neurons that project from the dorsal column nuclei to the diencephalon, pretectum and tectum in the cat. Somatosensory Res (in press)
Budell RJ, Berkley KJ (1983) Differences in thalamic- and spinal-projecting neurons in cat dorsal column nuclei. Soc Neurosci Abstr 9: (in press).
Burton H, Loewy AD (1977) Projections to the spinal cord from medullary somatosensory nuclei. J Comp Neurol 173: 773–792
Cole JD, Gordon G, Sanders DJ (1984) Physiological properties of dorsal column nuclear cells of the cat which project into the spinal cord. J Physiol (Lond): in press
Craig AD (1978) Spinal and medullary input to the lateral cervical nucleus. J Comp Neurol 181: 729–744
Dart AM (1971) Cells of the dorsal column nuclei projecting down into the spinal cord. J Physiol (Lond) 219: 29–30P
Dart AM (1972) A study of the functional relationships between the dorsal column and spinocervical systems of the cat. Thesis, Oxford University
Dart AM, Gordon G (1975) Some properties of spinal connections of the cat's dorsal column nuclei that do not involve the dorsal columns. In: Kornhuber HH (ed) The Somatosensory System. Thieme, Stuttgart, pp 176–181
Ellis LC, Rustioni A (1981) A correlative HRP, Golgi and EM study of the intrinsic organization of the feline dorsal column nuclei. J Comp Neurol 197: 341–367
Enevoldson TP, Gordon G, Sanders DJ (1984) The use of retrograde transport of horseradish peroxidase for studying the dendritic trees and axonal courses of particular groups of tract cells in the spinal cord. A modified procedure and its evaluation in the cat and rat. Exp Brain Res 54: 529–537
Fyffe REW, Light AR, Rustioni A (1982) Cuneo-thalamic neurones in the cat; an intracellular HRP study. J Physiol (Lond) 322: 29–30P
Gordon G, Grant G (1982) Dorsolateral spinal afferents to some medullary sensory nuclei. An anatomical study in the cat. Exp Brain Res 46: 12–23
Gordon G, Jukes MGM (1964) Dual organization of the exteroceptive components of the cat's gracile nucleus. J Physiol (Lond) 173: 263–290
Grant G (1962) Spinal course and somatotopically localized termination of the spinocerebellar tracts. An experimental study in the cat. Acta Physiol Scand 56: Suppl 193
Hand PJ (1966) Lumbosacral dorsal root terminations in the nucleus gracilis of the cat. J Comp Neurol 126: 137–156
Kleider A (1974) A functional study of some inputs and outputs of the cat's dorsal column nuclei. Thesis, Oxford University
Kuypers HGJM, Maisky VA (1975) Retrograde axonal transport of horseradish peroxidase from spinal cord to brainstem cell groups in the cat. Neurosci Lett 1: 9–14
Kuypers HGJM, Maisky VA (1977) Funicular trajectories of descending brainstem pathways in the cat. Brain Res 136: 159–165
Kuypers HGJM, Tuerk JD (1964) The distribution of the cortical fibres within the nuclei cuneatus and gracilis of the cat. J Anat (Lond) 98: 143–162
Mountcastle VB (1960) Some functional properties of the somatic afferent system. In: Rosenblith WA (ed) Sensory Communication, Cambridge, MA, MIT Press
Rustioni A (1973) Non-primary afferents to the nucleus gracilis from the lumbar cord of the cat. Brain Res 51: 81–95
Rustioni A (1974) Non-primary afferents to the cuneate nucleus in the brachial dorsal funiculus of the cat. Brain Res 75: 247–259
Rustioni A, Macchi G (1968) Distribution of dorsal root fibers in the medulla oblongata of the cat. J Comp Neurol 134: 113–126
Rustioni A, Molenaar I (1975) Dorsal column nuclei afferents in the lateral funiculus of the cat. Distribution pattern and absence of sprouting after chronic deafferentation. Exp Brain Res 23: 1–12
Sanders DJ (1983) Structural and functional inter-relationships of spinally projecting neurones in the dorsal column nuclei of the rat with other somaesthetic mechanisms. Thesis, Oxford University
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Enevoldson, T.P., Gordon, G. Spinally projecting neurons in the dorsal column nuclei: Distribution, dendritic trees and axonal projections. Exp Brain Res 54, 538–550 (1984). https://doi.org/10.1007/BF00235479
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DOI: https://doi.org/10.1007/BF00235479