Experimental Brain Research

, Volume 3, Issue 2, pp 117–134

Effects from the sensorimotor cortex on the spinal cord in cats with transected pyramids

  • T. Hongo
  • E. Jankowska

DOI: 10.1007/BF00233257

Cite this article as:
Hongo, T. & Jankowska, E. Exp Brain Res (1967) 3: 117. doi:10.1007/BF00233257


Effects of stimulation of the sensorimotor cortex on activity of the lumbosacral cord were studied in pyramidotomized cats. The following actions initiated by corticofugal volleys were found: 1. postsynaptic effects on motoneurones, mainly excitatory in flexor motoneurones and inhibitory or excitatory in extensor motoneurones, 2. facilitation of spinal reflexes to motoneurones at an interneuronal level, 3. depolarization of presynaptic terminals of group Ib and cutaneous fibres. The latencies of the earliest cortical effects on motoneurones as indicated by modification of monosynaptic reflexes or PSPs were 9–12 msec. Experiments with lesions of different spinal tracts suggest that the effects on motoneurones are mediated mainly by pathways in the ventral part of the lateral funiculus (probably reticulospinal), the facilitation of reflex transmission by pathways in the dorsal part of the lateral funiculus (probably rubrospinal) and primary afferent depolarization by both the former and the latter pathways. The strongest cortical effects were evoked by stimulation of an area around the postcruciate dimple.

Key Words

Supraspinal effects Extrapyramidal pathways Spinal activity Cat 

Copyright information

© Springer-Verlag 1967

Authors and Affiliations

  • T. Hongo
    • 1
    • 2
  • E. Jankowska
    • 1
    • 3
  1. 1.Department of PhysiologyUniversity of GöteborgSweden
  2. 2.Department of NeurophysiologyNencki Institute of Experimental BiologyWarsawPoland
  3. 3.Department of PhysiologyTokyo Medical and Dental UniversityTokyoJapan

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