Groups Of Motoneurons Research Articles

Effect of stimulation of different parts of the brain stem on reflex activity of a group of spinal cord extensor motoneurons

Effect of stimulation of different parts of the brain stem on reflex activity of a group of spinal cord extensor motoneurons

Responses of motoneurons of different sizes to graded stimulation of supraspinal centers of the brain.

ArticlesRESPONSES OF MOTONEURONS OF DIFFERENT SIZES TO GRADED STIMULATION OF SUPRASPINAL CENTERS OF THE BRAINGeorge Somjen, David O. Carpenter, and Elwood HennemanGeorge Somjen, David O. Carpenter, and Elwood HennemanPublished Online:01 Sep 1965https://doi.org/10.1152/jn.1965.28.5.958MoreSectionsPDF (1 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByChanges in Spinal Excitability After PASSabine Meunier, Heike Russmann, Marion Simonetta-Moreau, and Mark Hallett1 April 2007 | Journal of Neurophysiology, Vol. 97, No. 4Morphine withdrawal-induced abnormalities in the VTA: confocal laser scanning microscopy31 January 2003 | European Journal of Neuroscience, Vol. 17, No. 3Recruitment of Cat Motoneurons in the Absence of Homonymous Afferent FeedbackValerie K. Haftel, Jonathan F. Prather, C. J. Heckman, and Timothy C. Cope1 August 2001 | Journal of Neurophysiology, Vol. 86, No. 2Recruitment threshold force and its changing type of motor units during voluntary contraction at various speeds in manBrain Research, Vol. 372, No. 1ACTH/MSH 4–10 improves motor unit reorganization during peripheral nerve regeneration in the ratPeptides, Vol. 6Facility of motor unit control during tasks defined directly in terms of unit behaviorsExperimental Neurology, Vol. 59, No. 3Descending long-spinal excitation of lumbar alpha and gamma motoneurons evoked by stretch of dorsal neck musclesBrain Research, Vol. 140, No. 1Velocity of supraspinal input and conduction velocity of axons of spinal motoneuronsBrain Research, Vol. 120, No. 1Audio-spinal influence in man studied by the H-reflex and its possible role on rhythmic movements synchronized to soundElectroencephalography and Clinical Neurophysiology, Vol. 41, No. 1Recruitment and firing rate modulation of motor unit tension in a small muscle of the cat's footBrain Research, Vol. 98, No. 1A model for repetitive firing in neuronsKybernetik, Vol. 16, No. 1Rhythmic activity of a group of human motoneurones during voluntary contraction of a muscleElectroencephalography and Clinical Neurophysiology, Vol. 36Maintained activity of single neurons in striate and non-striate areas of the cat visual cortexBrain Research, Vol. 54The startle and orienting reactions in man. A study of their characteristics and habituationBrain Research, Vol. 18, No. 1 More from this issue > Volume 28Issue 5September 1965Pages 958-965 https://doi.org/10.1152/jn.1965.28.5.958PubMed5867887History Published online 1 September 1965 Published in print 1 September 1965 Metrics

Excitability and inhibitability of motoneurons of different sizes.

Excitability and inhibitability of motoneurons of different sizes.

PATTERN OF DISCHARGE OF FLEXOR MOTONEURONS.

ArticlesPATTERN OF DISCHARGE OF FLEXOR MOTONEURONSVictor J. Wilson, and William H. TalbotVictor J. Wilson, and William H. TalbotPublished Online:01 May 1964https://doi.org/10.1152/jn.1964.27.3.451MoreSectionsPDF (2 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformationCited ByGeneration of spike trains in CNS neuronsBrain Research, Vol. 84, No. 1Rhythmic activity of a group of human motoneurones during voluntary contraction of a muscleElectroencephalography and Clinical Neurophysiology, Vol. 36Synaptic potential summation and repetitive firing mechanisms: Input-output theory for the recruitment of neurons into epileptic bursting firing patternsBrain Research, Vol. 39, No. 1 More from this issue > Volume 27Issue 3May 1964Pages 451-463 https://doi.org/10.1152/jn.1964.27.3.451PubMed14170132History Published online 1 May 1964 Published in print 1 May 1964 Metrics

Spatial facilitation in the direct inhibitory pathway.

OF the various inhibitory actions converging on to spinal motoneurones the ‘direct’ inhibition is the one that has been the most extensively investigated1–6. It is provoked by impulses in large muscle afferents from annulo-spinal endings (Ia fibres)7–9. Monosynaptic excitatory action to motoneurones is also supplied by Ia fibres, and, with any particular group of motoneurones, the inhibitory action is caused by Ia fibres originating from the muscles antagonistic to those supplying excitatory action. The ‘direct’ inhibitory action is caused by a brief hyperpolarization of the motoneuronal membrane, the inhibitory post-synaptic potential10. The inhibitory post-synaptic potentials have a minimal latency of about 1.2–1.4 msec. relative to the time when the Ia volley reaches the spinal cord or approximately 0.8 msec. longer than for the monosynaptic excitatory post-synaptic potential. It has been postulated that this longer latency is due to the existence of an interneurone in the ‘direct’ inhibitory pathway, and experimental evidence has been presented suggesting that these interneurones are located in the intermediate nucleus11.

The relation of the magnitudes of remaining reflex shortening in two antagonistic muscles during compound stimulation

In a decerebrate cat, a flexion-producing stimulus evokes reflex shortening of a flexor muscle and “inhibitory” relaxation of extensor tone, i. e ., lengthening of the antagonistic extensor muscle. An extension-producing stimulus evokes reflex shortening in the extensor muscle of the antagonistic pair but, as there is no flexor tone, no measurable phenomena occur in the flexor muscle. If those two antagonistic stimuli are applied concurrently, a common phenomenon is the occurrence of some degree of shortening synchronously in both muscles of the antagonistic pair. On theoretical ground it is supposed that a simple flexion-producing stimulus evokes increase of discharge in the motor neurones which serve flexor muscles and “inhibition” of any discharge occurring at the time in the motor neurones which serve the antagonistic extensor. Similarly, an extension-producing stimulus is supposed to give concurrent increase of discharge in extensor moto-neurones and “inhibition” in flexor moto-neurones. A compound reflex is evoked when both these stimuli are applied concurrently, and a common (but not invariable) observation is that neither of the muscles in question shortens so greatly in the compound reflex as it does in its proper simple reflex. If the compound phenomena are regarded from the aspect of the effect upon either simple reflex of compounding it with an antagonistic simple reflex, both muscles appear to relax (lengthen). Sherrington has described this compound reflex effect as “algebraic summation.” It has often been assumed, sometimes tacitly, that the “excitation” and “inhibition” produced by a reflex stimulus are equal, and that the compound effect of two antagonistic reflex stimuli is produced by the algebraic summation in either group of moto-neurones ( i. e ., in either of what the writer has termed the antagonistic “half-centres”) of the “excitation” and “inhibition” produced in it by the two antagonistic reflex stimuli. A corollary to this is that the “reciprocal” relationship of two antagonistic muscles is governed by the “excitation” of one and the equal “inhibition” of the other evoked by a reflex stimulus.