HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Appelberg, B. Articles by Sojka, P. Search for Related Content PubMed PubMed Citation Articles by Appelberg, B. Articles by Sojka, P.

Department of Physiology, University of Umeå, S-901 87 Umeå, Sweden

Brain Research Institute, University of Zürich, August-Forel-Strasse 1, CH-8029 Zürich, Switzerland

1. Experiments were performed in forty-one cats anaesthetized with chloralose.

2. The aim of the study was to investigate whether activity in stretch-sensitive muscle receptors may cause reflex effects in fusimotor neurones.

3. Activity in fusimotor neurones was studied indirectly by recording from primary and secondary muscle spindle afferents of the triceps surae muscle. The mean rate of firing of the afferents as well as either dynamic index (during ramp extension) or modulation (during sinusoidal extension) was determined. This was done under control conditions, with the posterior biceps—semitendinosus muscles relaxed, and under test conditions, with the same muscles extended.

4. All together, seventy-one primary afferents were studied quantitatively. Pure or predominantly dynamic effects were observed in twenty-two, pure or predominantly static effects in nine and no statistically significant effects in forty of the units. Amongst seven secondary afferents studied, two showed weak fusimotor activation, the other five were not influenced.

5. Electrical stimulation of the posterior biceps—semitendinosus or medial gastrocnemius nerves at group II strength was observed to cause dynamic fusimotor reflexes on a number of occasions.

6. The reflex effects observed were, on many occasions, recorded in spinalized preparations.

7. The reflex effects were not accompanied by any detectable e.m.g. activity in triceps, as judged from surface e.m.g. recordings. The reflex effects observed are therefore tentatively ascribed to activation of -motoneurones, yet a contribution from -motoneurones cannot wholly be excluded.

8. On the basis of available evidence concerning reflex connexions to -motoneurones from various muscle afferents, it is suggested that the effects observed were caused by activation of muscle spindle secondary endings.

This article has been cited by other articles:

				R. Cueva-Rolon, R. Delgado-Lezama, J. G. Raya, M. Raya, R. Tecuanhuey, and E. J. Munoz-Martinez Sustained Firing of Alpha and Gamma Hind Limb Motoneurons Induced by Stimulation of the Pudendal Nerve J Neurophysiol, December 1, 2002; 88(6): 3232 - 3242. [Abstract] [Full Text] [PDF]