Summary
The effective spread of stimulating current for pyramidal tract (PT) cells and fibers was studied using a method of cancelling the shock artifacts and the following results were obtained:
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1.
The excitability of PT axon collaterals was as high as that of PT cells.
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2.
These axon collaterals extended as far as 1.0 mm horizontally from the PT cells.
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3.
The low threshold area for activation of a given PT cell was as wide as 3–4 mm2 on the surface of the cortex.
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4.
Intracortical microstimulation (ICMS) delivered to the PT cell layer produced direct (D) and indirect (I) descending volleys in the pyramidal tract, but ICMS to the superficial layer (III) produced only I-waves.
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5.
These I-waves grew significantly larger after 15–20 msec from the start of the train of stimuli.
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6.
It is concluded that either surface stimulation, or short train of ICMS is inadequate for delineating fine localization of motor function within the cortex. Longer train (30–40 msec) with high frequency pulses (300–400 cy/sec) can produce muscle contraction with much smaller currents, increasing the accuracy of measuring the localization of motor function.
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References
Andersen, P., Hagan, P.J., Phillips, C.G., Powell, T.P.S.: Mapping by microstimulation of overlapping projections from area 4 to motor units of the baboon's hand. Proc. Roy. Soc. B 188, 31–60 (1975)
Asanuma, H.: Recent development in the study of the columnar arrangement of neurons within the motor cortex. Physiol. Rev. 55, 143–156 (1975)
Asanuma, H., Arnold, A.P.: Noxious effects of excessive currents used for intracortical micro-stimulation. Brain Res. 96, 103–107 (1975)
Asanuma, H., Fernandez, J., Scheibel, M.E., Scheibel, A.B.: Characteristics of projections from the nucleus ventralis lateralis to the motor cortex in the cats: an anatomical and physiological study. Exp. Brain Res. 20, 315–330 (1974)
Asanuma, H., Hunsperger, R.W.: Functional significance of projection from the cerebellar nuclei to the motor cortex in the cat. Brain Res. 98, 73–92 (1975)
Asanuma, H., Rosén, L: Topographical organization of cortical efferent zones projecting to distal forelimb muscles in the monkey. Exp. Brain Res. 14, 243–256 (1972)
Asanuma, H., Rosén, I.: Spread of mono- and polysynaptic connections within cat's motor cortex. Exp. Brain Res. 16, 507–520 (1973)
Asanuma, H., Stoney, S.D., Jr., Abzug, C.: Relationship between afferent input and motor out-flow in cat motorsensory cortex. J. Neurophysiol. 31, 670–681 (1968)
Asanuma, H., Ward, J.E.: Patterns of contraction of distal forelimb muscles produced by intracortical stimulation in cats. Brain Res. 27, 97–109 (1971)
BeMent, S.L., Ranck, J.B., Jr.: A quantitative study of electrical stimulation of central myelinated fibers. Exp. Neurol. 24, 147–170 (1969)
Colonnier, M.L.: The structural design of the neocortex. In: Brain and Conscious Experience (ed. J.C. Eccles), p. 1–23. New York-Heidelberg-Berlin: Springer 1966
Hern, J.E.C., Landgren, S., Phillips, C.G., Porter, R.: Selective excitation of corticofugal neurones by surface-anodal stimulation of the baboon's motor cortex. J. Physiol. (Lond.) 161, 73–90 (1962)
Hern, J.E.C., Phillips, C.G., Porter, R.: Electrical thresholds of unimpaled corticospinal cells in the cat. Quart. J. exp. Physiol. 47, 134–140 (1962)
Hess, R., Negishi, K., Creutzfeldt, O.: The horizontal spread of intracortical inhibition in the visual cortex. Exp. Brain Res. 22, 415–419 (1975)
Hubel, D.H., Wiesel, T.N.: Shape and arrangement of columns in cat's striate cortex. J. Physiol. (Lond.) 165, 559–568 (1963)
Jankowska, E., Padel, Y., Tanaka, R.: The mode of activation of pyramidal tract cells by intracortical stimuli. J. Physiol. (Lond.) 249, 617–636 (1975a)
Jankowska, E., Padel, Y., Tanaka, R.: Projections of pyramidal tract cells to α-motoneurones innervating hind-limb muscles in the monkey. J. Physiol. (Lond.) 249, 637–667 (1975b)
Jankowska, E., Roberts, W.J.: An electrophysiological demonstration of the axonal projections of single spinal interneurones in the cat. J. Physiol. (Lond.) 222, 597–622 (1972)
Jankowska, E., Smith, D.O.: Antidromic activation of renshaw cells and their axonal projections. Acta physiol. scand. 88, 198–214 (1973)
Klüver, H., Barrera, E.: A method for the combined staining of cells and fibers in the nervous system. J. Neuropath, exp. Neurol. 12, 400–403 (1953)
Landgren, S., Phillips, C.G., Porter, R.: Minimal synaptic action of pyramidal impulses on some alpha motoneurons of the baboon's hand and'forearm. J. Physiol. (Lond.) 161, 91–111 (1962)
Mountcastle, V.B.: Modality and topographic properties of single neurons of cat's somatic sensory cortex. J. Neurophysiol. 20, 408–434 (1957)
Murphy, J.T., Wong, Y.C., Kwan, H.C.: Afferent-efferent linkages in motor cortex for single forelimb muscles. J. Neurophysiol. 38, 990–1014 (1975)
Nieoullon, A., Rispal-Padel, L.: Somatotopic localization in cat motor cortex. Brain Res. 105, 405–422 (1976)
Patton, H.D., Amassian, V.E.: Single- and multiple-unit analysis of cortical stage of pyramidal tract activation. J. Neurophysiol. 17, 345–363 (1954)
Phillips, C.G.: Actions of antidromic pyramidal volleys on single betz cells in the cat. Quart. J. exp. Physiol. 44, 1–25 (1959)
Rosenthal, J., Waller, H.J., Amassian, V.E.: An analysis of the activation of motor cortical neurons by surface stimulation. J. Neurophysiol. 30, 844–858 (1967)
Ruch, T.C.: The cerebral cortex: its structure and motor function. In: Physiology and Biophysics (eds. T.C. Ruch and H.D. Patton), p. 252–273. Philadelphia: Saunders 1965
Sherrington, C.: The integrative action of the nervous system. Yale University Press, 1906. Reprinted in 1947
Shinoda, Y., Arnold, A.P., Asanuma, H.: Spinal branching of corticospinal axons in the cat. Exp. Brain Res. (in press)
Stoney, S.D., Jr., Thompson, W.D., Asanuma, H.: Excitation of pyramidal tract cells by intracortical microstimulation: effective extent of stimulating current. J. Neurophysiol. 31, 659–669 (1968)
Stefanis, C., Jasper, H.: Intracellular microelectrode studies of antidromic pyramidal tract neurons. J. Neurophysiol. 27, 828–854 (1964)
Szentágothai, J.: Architecture of the cerebral cortex. In: Basic Mechanisms of the Epilepsies (eds. H.H. Jasper, A.A. Ward and A. Pope), p. 13–28. Boston: Little Brown 1969
Takahashi, K., Kubota, K., Uno, M.: Recurrent facilitation in cat pyramidal cells. J. Neurophysiol. 30, 22–34 (1967)
Wall, P.D.: Excitability changes in afferent fiber terminations and their relation to slow potentials. J. Physiol. (Lond.) 142, 1–21 (1958)
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Dr. A. Arnokd was the recipient of the NIH Fellowship 1-S22-MH 00559.
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Asanuma, H., Arnold, A. & Zarzecki, P. Further study on the excitation of pyramidal tract cells by intracortical microstimulation. Exp Brain Res 26, 443–461 (1976). https://doi.org/10.1007/BF00238820
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DOI: https://doi.org/10.1007/BF00238820