Phase Of Reflex Research Articles

Proprioceptive influences on inferior olivary neurons during phasic reflex movement in the cat

The origin of the climbing fiber system from the inferior olive, and its precise synaptic relation with the cerebellar Purkinje cells suggests that the spinoolivocerebellar pathway may contribute to the mechanism of a phasic reflex movement. Intracellular recordings of inferior olivary cells were obtained using glass capillary electrodes in nonanesthesized decerebrate cats during spontaneous clonus of the right gastrocnemius-soleus muscle. Inferior olivary cells were identified as responding to proprioceptive input from the gastrocnemius-soleus muscle by their activation to electrical stimulation and manual stretch of the tendon. Simultaneous records of the inferior olivary cell and the gastrocnemius-soleus myogram and EMG were obtained. Impaled inferior olivary cells were iontophoretically injected with fast green dye and identified histologically by Nissl counterstaining. Impaled inferior olivary cells activated during spontaneous clonus were recorded firing during the contraction phase of the phasic reflex. These results suggest a supraspinal influence on phasic reflex movement via the climbing fiber system based on the established inhibitory output of the Purkinje cells and the spinal inhibitory influence of the Golgi tendon organs during the contraction phase of the phasic reflex. It is suggested that the inhibitory supraspinal influence may combine with the spinal inhibitory influence to assist in inactivating the contraction phase of the phasic reflex.

Afferent and efferent activation of human muscle receptors involved in reflex and voluntary contraction

Single-unit activity from muscle nerve fibers was recorded with tungsten electrodes from the median nerve in unanaesthetized normal human subjects. Afferents were identified from individual Golgi tendon organs or muscle spindles during the phasic stretch reflex and the electrically stimulated twitch contraction. When the phasic reflex was initiated during a slight voluntary contraction, Golgi tendon organ firing was recorded in the postreflex silent period. In the electrically induced twitch contraction the muscle spindle fired a phasic burst of impulses during the relaxation phase of the contraction. This latter test proved to be highly reproducible and useful in verifying the dynamic sensitivity of the spindle. In a voluntary contraction, the Golgi receptor was activated in relation to the force of contraction, and during the relaxation phase of the contraction the receptor was inactivated. Muscle spindle firing was usually coactivated with the EMG, but not in a strict relation to the force of contraction. From some muscle spindles on minimal contraction a decrease in firing frequency was seen, and with stronger contraction the firing frequency was increased. At rest the spontaneous firing of muscle spindles was irregular, with the frequency varying with the degree of subject attention. Such tests as mental activity and acoustic arousal facilitated muscle spindle firing while Golgi tendon organs were not activated. During reinforcement maneuvers initiated by the contraction of remote leg muscles, muscle spindle spontaneous firing from the forearm flexor muscles was accelerated. The results supplement the criteria for individual human muscle receptor identification and establish the role of the receptors during reflex and voluntary muscle contraction and involuntary efferent receptor activation.

Human phasic reflex response to parameters of a mechanical stimulus as an index of muscle-spindle sensitivity.

The relationship between three parameters of a tendon tap used as the stretch stimulus (peak force, rate of increase of force and total duration of the tap) and the phasic stretch reflex-measured by the muscle-action potential (m.a.p.), were examined statistically using a multiple regression analysis. It was found with relaxed, normal humans in a stimulus-attenuated environment that the peak force of the tap was the most significant parameter in determining the response. Under these conditions the primary ending of the muscle spindle appears to be more sensitive to the peak force applied to the tendon than the other two parameters measured.

Thalamocortical projection system in motor-defensive reflexes

Chronic experiments on five dogs showed that preliminary bilateral lesions of the thalamic posteroventral nuclei (VP) and partial lesions in the posterior nuclear group of the thalamus increased the time required to form a stable postural response; sharply reduced (to 25–30% of all responses) the total “avoidance” level of the current, i. e., the production level of a correct postural response; and strengthened the defensive (phasic) reflex component. If the same thalamic zones were destroyed after preliminary formation and stabilization of motor defensive reflexes associated with maintenance of a certain posture, no marked changes were produced in these reflexes. To analyze the results the somatosensory cortical areas were stimulated through preliminarily implanted electrodes in a group of animals and areas S1 and S2 were removed from one experimental animal.

Are spinal “presynaptic” inhibitory mechanisms suppressed in spasticity?

The effect of muscle vibration on tendon jerks and H reflexes was studied in 18 spastic patients. Vibration applied anywhere to the limb of normal subjects effectively suppresses or abolishes the phasic reflexes, but in spastic patients vibration had little effect, any recordable suppression being maximal when vibrating the homonymous muscle. It is suggested that these differences between normal and spastic man are best explained by suppression of “presynaptic” inhibitory mechanisms in spasticity. It is postulated that the absence of these inhibitory mechanisms plays a significant role in the increased muscle tone of spasticity.

Differences in recruitment order of motor units in phasic and tonic flexion reflex in `spinal man'

The recruitment order of motoneurones in muscle contractions has been held to be largely constant and determined by the size of the cell. However, as shown in a previous investigation using electromyographic techniques, the order in which different motor units are activated during voluntary muscle contractions changes in normal human subjects on shifts from phasic to tonic contraction. In order to investigate these two types of activity also in cases in which the cerebral influence on the motoneurone pool is blocked, an analysis was made of the recruitment order in phasic and tonic flexion reflexes in 10 patients with total interruption of the spinal cord. The following four principles were found to apply and presumed to be generally valid for the isolated human spinal cord: (1) in the phasic exteroceptive reflex, the order of recruitment varies despite application of a standardized stimulus; (2) in the tonic reflex, the first unit to be recruited is usually the same even with widely different types of stimuli; (3) a shift from phasic to tonic reflex activation may result in considerable changes in recruitment order; (4) after facilitation by a subliminal long-lasting stimulus, the first unit to be recruited in the phasic reflex is also the first to be recruited in the tonic reflex. It is suggested that a tonic influence on the motoneurone pool is required for the presupposed constancy of the recruitment order.

Differential effects on tonic and phasic reflex mechanisms produced by vibration of muscles in man.

Differential effects on tonic and phasic reflex mechanisms produced by vibration of muscles in man.

MECHANISMS OF SUPRASPINAL ACTIONS UPON SPINAL CORD ACTIVITIES. DIFFERENCES BETWEEN RETICULAR AND CEREBELLAR INHIBITORY ACTIONS UPON ALPHA EXTENSOR MOTONEURONS.

ArticlesMECHANISMS OF SUPRASPINAL ACTIONS UPON SPINAL CORD ACTIVITIES. DIFFERENCES BETWEEN RETICULAR AND CEREBELLAR INHIBITORY ACTIONS UPON ALPHA EXTENSOR MOTONEURONSRodolfo LlinasRodolfo LlinasPublished Online:01 Nov 1964https://doi.org/10.1152/jn.1964.27.6.1117MoreSectionsPDF (1 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInEmailWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformationCited ByEffects of Neuromodulation on Gait31 January 2018Cortical Excitability Changes in Patients with Sleep-Wake Disturbances after Traumatic Brain InjuryJournal of Neurotrauma, Vol. 28, No. 7Changes in the motor pattern of learned and unlearned responses following cerebellar lesions: A kinematic analysis of the nictitating membrane reflexNeuroscience, Vol. 47, No. 1Synaptic mechanisms of interaction between Deiters' nucleus and the nuclei of some cranial nervesNeuroscience, Vol. 24, No. 1Startle responses recorded in the leg of manElectroencephalography and Clinical Neurophysiology, Vol. 39, No. 4The differential action of intravenous lidocaine on cerebellar inhibition and cerebellar disfacilitationBrain Research, Vol. 77, No. 3Proprioceptive influences on inferior olivary neurons during phasic reflex movement in the catExperimental Neurology, Vol. 44, No. 2The blockade of bulbospinal inhibition by imipramine, desipramine and pargylineNeuropharmacology, Vol. 13, No. 7Brain stem-thalamus reciprocal influences in the catBrain Research, Vol. 69, No. 2Nature of the midbrain influences upon thalamic neuronsBrain Research, Vol. 49, No. 1Morphine and meperidine on bulbospinal inhibition of the monosynaptic reflexEuropean Journal of Pharmacology, Vol. 21, No. 1Effects of bicuculline on central inhibitionNeuropharmacology, Vol. 11, No. 6Suppression of presynaptic inhibition and cerebellar disfacilitation by bicucullineLife Sciences, Vol. 11, No. 3Audio-spinal reflex responses in decerebrate and chloralose anesthetized catsBrain Research, Vol. 36, No. 2Brain stem reticular effects on intralaminar thalamic neurons in the catBrain Research, Vol. 25, No. 3Effects de la stimulation électrique répétitive du vermis au cours du sommeil avec activité corticale rapidePhysiology & Behavior, Vol. 6, No. 2Effects of diphenylaminoethanol and lidocaine on central inhibitionInternational Journal of Neuropharmacology, Vol. 8, No. 3Nature of the cerebellar influences upon the red nucleus neurones1 December 1968 | Experimental Brain Research, Vol. 4, No. 4 More from this issue > Volume 27Issue 6November 1964Pages 1117-1126 https://doi.org/10.1152/jn.1964.27.6.1117PubMed14223973History Published online 1 November 1964 Published in print 1 November 1964 Metrics