Summary
The locations of the cell bodies of origin of a pathway ascending in the dorsal part of the lateral funiculus of the cat spinal cord were mapped. It is presumed that the pathway is the spino-cervical tract. The locations of the neurons were determined by recording the antidromic action potentials in the lumbosacral enlargement evoked by stimulation of their axons at the third cervical segment, and then histologically reconstructing the recording sites. The cells were found to be scattered throughout laminae 4–6 of the dorsal horn, although most were in laminae 4 and 5. The conduction velocities of the axons ranged from 7 to 90 m/sec (mean 44 m/sec). A somatotopic relationship was observed between the locations of the cells within the dorsal horn and the distributions of their peripheral receptive fields. This somatotopic organization was oriented with respect to rostrocaudal and dorso-ventral axes as determined for the adult hindlimb by reference to its fetal development. The axes become distorted during development, but are still recognizable in the adult. Cells receiving afferent input from skin derived from rostral portions of the limb, including the medial surface of the adult foot, are located rostrally in the cord. The caudal limb, which includes the lateral surface of the foot in the adult, is represented caudally in the spinal cord. The dorsal limb or extensor surface projects to the lateral part of the dorsal horn, while the ventral limb or flexor surface is represented medially.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Andersen, P., Andersson, S.A., Landgren, S.: Some properties of the thalamic relay cells in the spino-cervico-lemniscal path. Acta physiol. scand. 68, 72–83 (1966).
Armett, C.J., Gray, J.A.B., Palmer, J.F.: A group of neurons in the dorsal horn associated with cutaneous mechanoreceptors. J. Physiol. (Lond.) 156, 611–622 (1961).
Brown, A.G., Franz, D.N.: Responses of spino-cervical tract neurons to natural stimulation of identified cutaneous receptors. Exp. Brain Res. 7, 231–249 (1969).
Bryan, R.N., Trevino, D.L., Willis, W.D.: Evidence for a common location of alpha and gamma motoneurons. Brain Res. 38, 193–196 (1972).
Eccles, J.C., Eccles, R.M., Lundberg, A.: Types of neurons in and around the intermediate nucleus of the lumbosacral cord. J. Physiol. (Lond.) 154, 89–114 (1960).
Gordon, G., Jukes, M.G.M.: Dual organization of the exteroceptive component of the cat's gracile nucleus. J. Physiol. (Lond.) 173, 263–290 (1964).
Gregor, M., Zimmermann, M.: Characteristics of spinal neurones responding to cutaneous myelinated and unmyelinated fibres. J. Physiol. (Lond.) 221, 555–576 (1972).
Hongo, T., Jankowska, E., Lundberg, A.: Postsynaptic excitation and inhibition from primary afferents in neurons of the spino-cervical tract. J. Physiol. (Lond.) 199, 569–592 (1968).
Kuhn, R.A.: Organization of tactile dematomes in cat and monkey. J. Neurophysiol. 16, 169–182 (1953).
Lundberg, A., Oscarsson, O.: Three ascending pathways in the dorsal part of the lateral funiculus. Acta physiol. scand. 51, 1–16 (1960).
Morin, F.: A new spinal pathway for cutaneous impulses. Amer. J. Physiol. 183, 245–252 (1955).
Patterson, A.M.: The position of the mammalian limb; regarded in the light of its innervation and development. J. Anat. Physiol. 23, 283–299 (1889).
Pubols, B.H., Pubols, L.M.: Forelimb, hindlimb, and tail dematomes in the spider monkey (Ateles). Brain Behav. Evol. 2, 132–159 (1969).
Rexed, B.: A cytoarchitectonic atlas of the spinal cord in the cat. J. comp. Neurol. 100, 297–380 (1954).
Sherrington, C.S.: Experiments in examination of the peripheral distribution of the fibres of the posterior roots of some spinal nerves. Phil. Trans. 184B, 641–765 (1893).
Stretton, A.O.W., Kravitz, E.A.: Neuronal geometry determination with a technique of intracellular dye injection. Science 162, 132–134 (1968).
Taub, A., Bishop, P.O.: The spino-cervical tract: Dorsal column linkage, conduction velocity, primary afferent spectrum. Exp. Neurol. 13, 1–21 (1965).
Trevino, D.L., Maunz, R.A., Bryan, R.N., Willis, W.D.: Location of cells of origin of the spino-thalamic tract in the lumbar enlargement of cat. Exp. Neurol. 34, 64–77 (1972).
Wall, P.D.: Cord cells responding to touch, damage, and temperature of skin. J. Neurophysiol. 23, 197–210 (1960).
Werner, G., Whitsel, B.L.: The topology of dermatomal projection in the medial lemniscal system. J. Physiol. (Lond.) 192, 123–144 (1967).
Whitsel, B.L., Dryer, D.A., Roppolo, J.R.: Determinants of body representation in post central gyrus of macaques. J. Neurophysiol. 34, 1018–1034 (1971).
Willis, W.D., Weir, M.A., Skinner, R.D., Bryan, R.N.: Differential distribution of spinal cord field potentials. Exp. Brain Res. 17, 169–176 (1973).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Bryan, R.N., Trevino, D.L., Coulter, J.D. et al. Location and somatotopic organization of the cells of origin of the spino-cervical tract. Exp Brain Res 17, 177–189 (1973). https://doi.org/10.1007/BF00235027
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00235027