Summary
The effect of a descending corticospinal volley on a spinal inhibitory pathway, has been studied in five intact human subjects. Approximately 63% inhibition of the H-reflex evoked in wrist and finger flexor muscles, was produced by motor threshold stimulation of the radial nerve. When a submotor threshold cortical shock was given 2 to 4 ms before the H-reflex, this inhibition was reduced to approximately 38%. The timing of this effect is compatible with either a monosynaptic or disynaptic corticospinal tract projection onto the spinal inhibitory interneurone.
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References
Baldissera F, Hultborn H, Illert M (1981) Integration in spinal neuronal systems. In: Brooks V (ed) Handbook of physiology, sect 1: The nervous system, vol 2, part 2. American Physiological Society, pp 509–593
Cowan J, Day BL, Marsden CD, Rothwell JC (1983) Effect of sub-threshold motor cortical shocks on the human spinal monosynaptic reflex. J Physiol (Lond) 341: 32–33
Day BL, Marsden CD, Obeso JA, Rothwell JC (1981) Peripheral and central mechanisms of reciprocal inhibition in the human forearm. J Physiol (Lond) 317: 59–60
Day BL, Rothwell JC (1983) Estimation of the central delay in the reciprocal Ia inhibitory pathway of the human forearm. J Physiol (Lond) 336: 32
Day BL, Rothwell JC, Marsden CD (1983) Transmission in the spinal reciprocal Ia inhibitory pathway preceding willed movements of the human wrist. Neurosci Lett 37: 245–250
Hultborn H (1976) Transmission in the pathway of reciprocal Ia inhibition to motoneurones and its control during the tonic stretch reflex. In: Homma S (ed) Progress in brain research understanding the stretch reflex, vol 44. Elsevier North Holland, Amsterdam, pp 235–255
Jankowska E, Padel Y, Tanaka R (1976) Disynaptic inhibition of spinal motoneurones from the motor cortex in monkey. J Physiol (Lond) 258: 467–487
Lundberg A, Voorhoeve P (1962) Effects from the pyramidal tract on spinal reflex arcs. Acta Physiol Scand 56: 201–219
Merton PA, Morton HB (1980) Stimulation of the cerebral cortex in the intact human subject. Nature (Lond) 285: 227
Tanaka R (1980) Inhibitory mechanism in reciprocal inhibition in voluntary movements. In: Desmedt JE (ed) Spinal and supraspinal mechanisms of voluntary motor control and locomotion. Karger, Basel, pp 117–128
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Rothwell, J.C., Day, B.L., Berardelli, A. et al. Effects of motor cortex stimulation on spinal interneurones in intact man. Exp Brain Res 54, 382–384 (1984). https://doi.org/10.1007/BF00236241
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DOI: https://doi.org/10.1007/BF00236241