Summary
Monkeys with chronic unilateral lesions of the pyramidal tract were investigated with respect to motor cortical effects on distal forelimb muscles. The forelimb area of the pre-central gyrus was stimulated with long single pulses or with repetitive pulses at 50/sec on both sides, one cortex having an intact pyramidal projection (control) and the other cortex having a lesion in its pyramidal projection varying from 30–100%. Repetitive stimulation at 50/sec of the intact cortex elicited, after a summation period of variable length, synchronized discharges following each stimulus pulse. Long single pulses (3 msec, 1/sec) were likewise effective to activate the distal forelimb muscles. Stimulation of the motor cortex with a lesion in its pyramidal projection was no longer effective to elicit discharges in the distal muscles when single pulses of up to 6 mA were used, even in the animal with a 30% lesion. With repetitive stimuli (1 msec, 50/sec) some activity was evoked in all animals including the monkey with a 100% lesion. The pattern of activation tended to be diffuse, i.e. not time-locked to the individual stimulus pulses. In the animals with smaller lesions the mean latency of discharges following the repetitive stimuli was increased as compared with the control side. The motor cortical effects in a 10 month old monkey were the same as in the adult monkey with intact pyramidal projection. The results of motor cortex stimulation in a 7 week old monkey were, however, similar to those obtained in adult monkeys with pyramidal lesions.
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References
Artom, G.: Untersuchungen über die Myelogenese des Nervensystems der Affen. Arch. Psychiat. Nervenkr. 75, 169–234 (1925).
Bernhard, C.G., Bohm, E., Petersen, I.: Investigations on the organization of the corticospinal system in monkey (Macaca mulatta). Acta physiol. scand. 29, Suppl. 106, 79–103 (1953).
—: Cortical representation and functional significance of the corticomotoneuronal system. Arch. Neurol. Psychiat. (Chic.) 72, 473–502 (1954).
Brown-Séquard, C. E.: Expériences montrant combien est grande la dissémination des voies motrices dans le bulbe rachidien. Arch. Physiol. norm. path. 1889, 606–608.
Cooper, S., Denny-Brown, D.: Responses to stimulation of the motor area of the cerebral cortex. Proc. Roy. Soc. B 102, 222–236 (1928).
Denny-Brown, D.: The cerebral control of movement, p. 154. Liverpool: University Press 1966.
Jankowska, E., Tarnecki, R.: Extrapyramidal activation of muscles from the sensori-motor cortex in cats. Experientia (Basel) 21, 656 (1965).
Kuypers, H.G.J.M.: The descending pathways to the spinal cord, their anatomy and function. Progr. Brain Res. 11, 178–202 (1964).
Landgren, S., Phillips, C.G., Porter, R.: Cortical fields of origin of the monosynaptic pyramidal pathways to some alpha motoneurones of the baboon's hand and forearm. J. Physiol. (Lond.) 161, 112–125 (1962).
Lawrence, D.G., Kuypers, H.G.J.M.: The functional organization of the motor system in the monkey. I. The effects of bilateral pyramidal lesions. Brain 91, 1–14 (1968a).
—: Functional organization of the motor system in the monkey. II. The effects of lesions of the descending brain-stem pathways. Brain 91, 15–36 (1968b).
Lewis, R., Brindley, G.S.: The extrapyramidal cortical motor map. Brain 88, 397–406 (1965).
Liddell, E.G.T., Phillips, C.G.: Overlapping areas in the motor cortex of the baboon. J. Physiol. (Lond.) 112, 392–399 (1951).
—: The cortical representation of motor units. Brain 75, 510–525 (1952).
Phillips, C.G., Porter, R.: The pyramidal projection to motoneurones of some muscle groups of the baboon's forelimb. Progr. Brain Res. 12, 222–245 (1964).
Tower, S.S.: The dissociation of cortical excitation from cortical inhibition by pyramid section and the syndrome of that lesion in the cat. Brain 58, 238–255 (1935).
—: Pyramidal lesion in the monkey. Brain 63, 36–90 (1940).
Tower, S.S.: The pyramidal tract. In: Bucy, P.C.: The precentral cortex, pp. 149–172. Urbana/Ill.: University of Illinois Press, 1944.
Wiesendanger, M.: The pyramidal tract. Recent investigations on its morphology and function. Ergebn. Physiol. 61, 72–136 (1969).
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Felix, D., Wiesendanger, M. Pyramidal and non-pyramidal motor cortical effects on distal forelimb muscles of monkeys. Exp Brain Res 12, 81–91 (1971). https://doi.org/10.1007/BF00234417
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DOI: https://doi.org/10.1007/BF00234417