Experimental Brain Research

, Volume 69, Issue 3, pp 449–459

Supraspinal control of a short-latency cutaneous pathway to hindlimb motoneurons

  • J. W. Fleshman
  • P. Rudomin
  • R. E. Burke
Article

DOI: 10.1007/BF00247299

Cite this article as:
Fleshman, J.W., Rudomin, P. & Burke, R.E. Exp Brain Res (1988) 69: 449. doi:10.1007/BF00247299

Summary

The effects of two supraspinal systems on transmission through a short latency hindlimb cutaneous reflex pathway were studied in cats anesthetized with pentobarbital or α-chloralose. Fleshman et al. (1984) described a mixed excitatoryinhibitory input from low threshold superficial peroneal (SP) afferents to flexor digitorum longus (FDL) motoneurons with central latencies so short as to suggest a disynaptic component in the initial excitatory phase of the PSP. In the present study, conditioning stimulation of either the red nucleus (RN) or the pyramidal tract (PT) caused a marked decrease in latency and increase in amplitude of both the excitatory and inhibitory components of the SP PSP in FDL motoneurons and several other motoneuron species. The minimal central latencies of the conditioned initial excitatory phase of the PSPs were on the order of 1.5 ms, consistent with the possibility of a disynaptic linkage. The facilitatory effects of RN and PT conditioning were observed in both anesthetic conditions, although preparation-specific differences in latency were observed. Lesion experiments suggested that the interneurons involved in this pathway are located caudal to the L5 segment, most likely in segments L6 and L7.

Key words

Spinal cordCutaneous reflexRed nucleusPyramidal tractSpatial facilitationExcitatory interneuronsDisynaptic pathway

Copyright information

© Springer-Verlag 1988

Authors and Affiliations

  • J. W. Fleshman
    • 1
  • P. Rudomin
    • 2
  • R. E. Burke
    • 1
  1. 1.Laboratory of Neural ControlBethesdaUSA
  2. 2.Department of PhysiologyCentro de Investigaciony Estudios Avanzados del IPNMexico 14 DFMexico
  3. 3.Systems Research CenterUniversity of MarylandCollege ParkUSA