J Physiol Wellcome Trust-funded researchers
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
 QUICK SEARCH:   [advanced]


     


J Physiol Vol 207, Issue 1 pp 103-118
Copyright © 1970 by The Physiological Society
This Article
Right arrow Full Text (PDF)
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Decima, E. E.
Right arrow Articles by Goldberg, L. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Decima, E. E.
Right arrow Articles by Goldberg, L. J.

Centrifugal dorsal root discharges induced by motoneurone activation

E. E. Decima and L. J. Goldberg

1. It has been confirmed that antidromic stimulation of motoneurones in the cat lumbar cord can induce, when properly conditioned, a centrifugal discharge in dorsal root afferent fibres.

2. The effective conditioning can be (a) an orthodromic volley to the same or an adjacent dorsal root, (b) a volley to the dorsal column one or two segments above the tested level, or (c) a natural stimulus applied to the ipsi- or contralateral hind limb.

3. The conditioning stimulus acts by increasing presynaptic excitability; the peak of its effect (maximum presynaptic depolarization) occurs 7-10 msec after the arrival of the conditioning volley to the cord and then quickly decays.

4. A large antidromic field potential in the ventral horn is not necessary for the production of a centrifugal dorsal root discharge. Activation of a ventral root filament of approximately 100 µ in diameter can still induce such a discharge in a single dorsal root fibre. Furthermore, antidromic stimulation of the remaining fibres of the same ventral root cannot affect the terminals activated by the thin ventral root filament.

5. The phenomenon of motoneurone—presynaptic interaction was obtained in different types of experimental preparations: acute and chronic spinal, anaemic and midcollicular decerebrate, animals with intact supraspinal centres, and one animal without acute laminectomy.







HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1970 The Physiological Society.