[Studies on pupillary near reflex. II. Studies on pathological pupillary near reflex. 1. On the pupillary near reflex on traumatic cranio-cervical syndrome].
Explore the source record for details and available documents.
Accommodation, Ocular↗
SEARCH · Search PubMed
Results for “REFLEX”
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Sensitivity of monosynaptic test reflexes to facilitation and inhibition as a function of the test reflex size: a study in man and the cat.
In parallel experiments on humans and in the cat it was investigated how the sensitivity of monosynaptic test reflexes to facilitation and inhibition varies as a function of the size of the control test reflex itself. In man the monosynaptic reflex (the Hoffmann reflex) was evoked in either the soleus muscle (by stimulation of the tibial nerve) or the quadriceps muscle (by stimulation of the femoral nerve). In the decerebrate cat monosynaptic reflexes were recorded from the nerves to soleus and medial gastrocnemius muscles; they were evoked by stimulation of the proximal ends of the sectioned L7 and S1 dorsal roots. Various excitatory and inhibitory spinal reflex pathways were used for conditioning the test reflexes (e.g. monosynaptic Ia excitation, disynaptic reciprocal inhibition, cutaneous inhibition, recurrent inhibition, presynaptic inhibition of the Ia fibres mediating the test reflex). It was shown that the additional number of motoneurones recruited in a monosynaptic test reflex by a constant excitatory conditioning stimulus was very much dependent on the size of the test reflex itself. This dependency had the same characteristic pattern whatever the conditioning stimulus. With increasing size of the test reflex the number of additionally recruited motoneurones first increased, then reached a peak (or plateau) and finally decreased. A similar relation was also seen with inhibitory conditioning stimuli. The basic physiological factors responsible for these findings are discussed. Finally, the implications for the interpretation of experiments in man with the H-reflex technique are considered.
Adolescent↗
Operant conditioning of primate spinal reflexes: the H-reflex.
The study of primate memory substrates, the CNS alterations which preserve conditioned responses, requires an experimental model that fulfills two criteria. First, the essential alterations must be in a technically accessible location. Second, they must persist without input from other CNS regions. The spinal cord is the most technically accessible and readily isolated portion of the primate CNS. Recent work has demonstrated that the spinal stretch reflex (SSR), the initial, wholly segmental response to muscle stretch, can be operantly conditioned and suggests that this conditioning may produce persistent spinal alteration. The present study attempted similar operant conditioning of the H-reflex, the electrical analog of the SSR. The primary goals were to demonstrate that spinal reflex conditioning can occur even if the muscle spindle is removed from the reflex arc and to demonstrate conditioning in the lumbosacral cord, which is far preferable to the cervical cord for future studies of neuronal and synaptic mechanisms. Nine monkeys prepared with chronic fine-wire triceps surae (gastrocnemius and soleus) electromyographic (EMG) electrodes were taught by computer to maintain a given level of background EMG activity. At random times, a voltage pulse just above M response (direct muscle response) threshold was delivered to the posterior tibial nerve via a chronically implanted silicon nerve cuff and elicited the triceps surae H-reflex. Under the control mode, reward always followed. Under the HR increases or HR decreases mode, reward followed only if the absolute value of triceps surae EMG from 12 to 22 ms after the pulse (the H-reflex interval) was above (HR increases) or below (HR decreases) a set value. Monkeys completed 3,000-6,000 trials/day over study periods of 2-3 mo. Background EMG and M response amplitude remained stable throughout data collection. H-reflex amplitude remained stable under the control mode. Under the HR increases mode (5 animals) or HR decreases mode (4 animals), H-reflex amplitude (EMG amplitude in the H-reflex interval minus background EMG amplitude) changed appropriately over at least 6 wk. Change appeared to occur in two phases: an abrupt change within the first day, followed by slower change, which continued indefinitely. Change occurred in all three triceps surae muscles (medial and lateral gastrocnemii and soleus). Under the HR increases mode, H-reflex amplitude rose to an average of 213% of control, whereas under the HR decreases mode it fell to an average of 68% of control. The results demonstrate that the H-reflex can be operantly conditioned.(ABSTRACT TRUNCATED AT 400 WORDS)
Animals↗
The influence of muscle spindle discharge on the human H reflex and the monosynaptic reflex in the cat.
1. Experiments were carried out to test the effect of changes in spindle resting discharge on the size of monosynaptic reflexes in the cat and on the H reflex in humans. Resting discharge was altered by contracting the triceps surae muscle at longer (hold-long) or shorter (hold-short) lengths than that at which the reflex was tested. 2. The reflex in the cat was larger after hold-long than after hold-short conditioning, and the difference, after an initial decline, was well maintained. For the human H reflex a similar pattern was observed except that 15 s after muscle conditioning the difference in reflex size had disappeared. 3. Monosynaptic reflex depression immediately after hold-long conditioning, when most of the muscle spindles are silent, was attributed to the high level of spindle discharge during the immediately preceding hold-long period. The time course of this inhibition was too long to be accounted for by presynaptic inhibition. 4. In the cat heteronymous muscle conditioning was used to test whether presynaptic inhibition could be responsible for reflex depression using the synergist muscle pair lateral gastrocnemius-soleus and medial gastrocnemius. Conditioning one of the pair did not affect the reflex in the other, the opposite result to that expected with presynaptic inhibition. A similar experiment in which the triceps H reflex in human subjects was facilitated by a quadriceps volley gave the same result. 5. Thus this study presents evidence that monosynaptic reflexes are depressed by the on-going discharge of muscle spindles in the homonymous muscle, but that this depression does not appear to involve "classical' presynaptic inhibition.
Adult↗
[Evaluation of the morphology of stapedial reflex in otosclerosis. Provoked otosclerotic stapedial reflex].
Stapedial reflex is used, amongst other pathologies, for the study of otosclerosis. In this retrospective study we have collected 188 cases of patients with otosclerosis whose diagnosis has been confirmed surgically and their first line relatives. We have performed a descriptive analysis of audiometric tests, tympanometries and ipsilateral stapedial reflexes in relation with the evolutive phase of the disease. Transmission hypoacusis has been seen in 54%, mixed hypoacusis in 29% and sensorineural hypoacusis 8% of cases. On and OFF stapedial reflexes have been seen in 18%, inverted reflexes in 46% and absent reflexes in 27% of cases. The original drawings of the different types of reflexes during the evolution of otosclerosis can be seen in the four figures shown in the study: normal reflexes; ON and OFF a, b and c types; inverted a and b; and absent reflexes. The clinical evolutive phase and the audiometric and impedance tests have been correlated. Through Chi-square (p < 0.001), we have obtained a statistical significance in relation to the use of stapedial reflexes. Also it has been suggested the use of provoked stapedial reflexes in patients with sub clinical otosclerosis in order to diagnose the disease. We conclude that the knowledge of the evolutive morphology os stapedial reflexes in otosclerosis helps diagnostic capacity.
Acoustic Impedance Tests↗
Effect of chronic and acute cigarette smoking on the pharyngo-upper oesophageal sphincter contractile reflex and reflexive pharyngeal swallow.
BACKGROUND: Cigarette smoking is known to affect adversely the defence mechanisms against gastro-oesophageal reflux. The effect of smoking on the supraoesophageal reflexes that prevent aspiration of gastric contents has not been previously studied. AIMS: To elucidate the effect of cigarette smoking on two of the supraoesophageal reflexes: the pharyngo-upper oesophageal sphincter (UOS) contractile reflex; and the reflexive pharyngeal swallow. METHODS: Ten chronic smokers and 10 non-smokers were studied, before and 10 minutes after real or simulated smoking, respectively. UOS pressure and threshold volume for the reflexes were determined using a UOS sleeve assembly. Two modes of fluid delivery into the pharynx were tested: rapid injection and slow injection. RESULTS: For both rapid and slow injections, the threshold volume for triggering the pharyngo-UOS contractile reflex was significantly higher in smokers than in non-smokers (rapid: smokers 0.42 (SE 0.07) ml, non-smokers 0.16 (0. 04) ml; slow: smokers 0.86 (0.06) ml, non-smokers 0.38 (0.1) ml; p<0. 05). During rapid injection, the threshold volume for reflexive pharyngeal swallow was higher in smokers (smokers 0.94 (0.09) ml, non-smokers 0.46 (0.05) ml; p<0.05). Acute smoking further increased the threshold volume for the pharyngo-UOS contractile reflex and reflexive pharyngeal swallow during rapid injection. CONCLUSIONS: Smoking adversely affects stimulation of the pharyngo-UOS contractile reflex and pharyngeal reflexive swallow. These findings may have implications in the development of reflux related respiratory complications among smokers.
Adult↗
[Cutaneo-muscular reflexes of the human hand. II. Neurophysiologic aspects of reflex organization and coordination].
The organization and coordination of cutaneo-muscular reflexes of human finger and arm muscles to electrical stimulation of the digital nerves were investigated in 14 healthy volunteers. Thumb and finger muscles, although antagonists, showed homonymous reflex effects whereas the wrist and elbow muscles exhibited an reciprocally alternating reflex pattern in pairs of antagonists (Fig. 1). The mechanographical correlate of the homonymous reflex activity in distal muscles was a short release (Fig. 6). The receptive field for evoking such reflex effects covered both the palmar and dorsal surfaces of the fingers (Fig. 2). However, with stimulation of the thumb, the muscles of the fingers and of the wrist showed reflex reversal (Figs 3, 5). If the stimulus was moved from the second to the fifth fingers, a successive attenuation of the transcortical reflex component was seen (Fig. 4). It is concluded that the reflexes investigated are complex flexor reflexes comprising both a distal release and a proximal flexion synergy. According to opposition of the thumb in grasping, the receptive field terminates between thumb and index finger. These reflexes are supposed to have no assisting function during corticalized manipulatory movements--in contrast to the long-loop reflexes evoked by epicritic sensibility. The transcortical servo is blocked if the eliciting stimulus is contaminated by nociceptive signals; its receptive field is confined to those fingers used in the precision grip.
Adult↗
Operant conditioning of primate triceps surae H-reflex produces reflex asymmetry.
Monkeys are able to increase or decrease triceps surae H-reflex when reward depends on reflex amplitude. Operantly conditioned change occurs over weeks and produces persistent alterations in the lumbosacral spinal cord which should be technically accessible substrates of primate memory. Previous work monitored and conditioned triceps surae H-reflex in one leg. To determine whether H-reflex conditioning in one leg affects the control leg, the present study monitored H-reflexes in both legs while the reflex in one leg underwent HR increases or HR decreases conditioning. Under the HR increases mode, H-reflex increase was much greater in the HR increases leg than in the control leg. Under the HR decreases mode, H-reflex decrease was confined to the HR decreases leg. By showing that conditioning of one leg's H-reflex produces H-reflex asymmetry, the data further define the phenomenon and indicate that the other leg can serve as an internal control for physiologic and anatomic studies exploring the sites and mechanisms of the spinal cord memory substrates.
Animals↗
Babinski reflex and the CUT reflex--a comparative study.
The Babinski reflex and the CUT reflex were examined in 150 neurological patients and 20 controls. A positive CUT reflex occurred more frequently than a positive Babinski reflex in the patient material as a whole, and in different diagnostic groups. However, there was a low grade of correspondence between a positive CUT reflex and a positive Babinski reflex. There were many positive CUT reflexes in the group of normal persons. In a number of cases the examination of the CUT reflex was impossible because of lack of strength or incooperability. The study indicates that the CUT reflex and the Babinski reflex are not comparable phenomena.
Adolescent↗
The plantar cushion reflex circuit: an oligosynaptic cutaneous reflex.
1. Reflex toe extension elicited by pressure on the plantar cushion (PC) was studied in cats anaesthetized with Dial. Receptive fields and adequate stimuli for the reflex were evaluated. It was concluded that the receptors for the reflex were chiefly cutaneous pressure receptors in PC.2. The fastest impulses from the PC receptors for this reflex are conducted to the spinal cord at about 64 m/sec via fibres about 10-11 mum in diameter, i.e. the largest afferent fibres from PC. The motoneurones active in the reflex mainly supplied the intrinsic plantar muscles. Most active axons ran in the S1 ventral root.3. Extracellular recordings of interneurones in the dorsal horn of L7 spinal segment revealed that many units at the medial edge of the dorsal horn, chiefly in Rexed's laminae IV and V, were activated by stimuli similar to those eliciting the PC-toe extension reflex. These were termed intermediate threshold PC units. Some of these medially located units were activated monosynaptically by PC stimulation. Intermediate threshold PC units activated disynaptically or polysynaptically were also found in this medial region of the dorsal horn, as well as ventrolaterally and caudally in lamina V.4. No intermediate threshold PC units sent axons into dorsolateral ipsilateral thoracic white matter, in contrast to lower threshold PC units, 42% of which were driven by lateral column stimulation.5. Extracellular and intracellular recordings were made from motoneurones activated by adequate stimuli for the reflex. Minimum latencies of EPSPs revealed that, for the fastest component of the reflex, at most two interneurones could be interposed between a primary sensory neurone and a motoneurone.6. Although convergence of low threshold PC units on to intermediate threshold PC units or on to motoneurones may play a part in the PC-toe extension reflex, it appears probable that the two populations of intermediate threshold PC interneurones described above, that is, the monosynaptic and the disynaptic (with higher order interneurones), mediate the reflex.
Action Potentials↗
Interaction between the vestibulo-collic reflex and the cervico-collic stretch reflex in the decerebrate cat.
1. Interactions between the sagittal vestibulo-collic reflex (v.c.r.) and the cervico-collic stretch reflex (c.c.r.) have been studied in the neck extensor muscles biventer cervicis (b.c.) in the decerebrate cat. The v.c.r. was evoked by a 'standard' vestibular stimulus consisting of a sinusoidal nose-up, nose-down head movement of 6-8 deg amplitude at 1 Hz. The c.c.r. was evoked by sinusoidal stretching of the b.c. muscles at 1 Hz. The amplitude of muscle stretching, and its phase in relation to head movement, were systematically varied. 2. When muscle stretching was applied in phase with head movement (so that the muscles were stretched as the head moved in the nose-down direction), the gain of the combined (v.c.r. + c.c.r.) reflex in the b.c. muscles increased above that of the v.c.r. If the muscle stretching was applied out of phase with head movement (so that the muscles shortened as the head moved downward), the gain of the combined reflex was reduced to a value below that of the v.c.r. 3. The effects on the gain of the combined reflex varied in proportion to the amplitude of muscle stretching. The gain and phase of the combined reflex is modelled reasonably well by a linear vectorial addition between the v.c.r. and the c.c.r. over a wide range of amplitudes of muscle stretching. The linear summation model contains a proportionality constant K, which may represent a factor by which the two reflexes are 'calibrated' against each other. 4. If one of the b.c. muscles was held at a fixed length and the other stretched sinusoidally, the c.c.r. was evoked only in the stimulated muscle. Vestibular stimulation then summed with the c.c.r in the stimulated muscle, while on the contralateral side the reflex response was the same as that of the v.c.r. alone. It would appear therefore that the motoneurone pools of the b.c. muscles are organized as independent entities without mutually excitatory or inhibitory reflex linkages. This arrangement presumably allows flexibility in the supraspinal control of the b.c. muscles, which are often used either as synergists during sagittal head movement or as antagonists during horizontal or roll movements of the head. 5. The interaction between the v.c.r. and the c.c.r. results in an apparent 'servo-assistance' role for the muscle afferent feed-back from the b.c. muscles, amplifying or attenuating the reflex response of the muscles to a given head movement.(ABSTRACT TRUNCATED AT 400 WORDS)
Animals↗
A neurophysiological approach to brainstem reflexes. Blink reflex.
The blink reflex (BR) is a generalised phenomenon in mammals. Its teleological protective eye function is perhaps the reason why the BR can be provoked by a multitude of stimuli. As corneal and glabellar reflexes, BR has an inveterate use in the neurological exploration. Some of its physiopathological aspects were discussed more than 100 years ago, and soon half a century will have passed since the first electrophysiological study was published. This review focuses on the BR elicited by the electrical stimulation of the trigeminal supraorbital nerve, a controlled and reliable model in clinical neurophysiology. The electrically elicited BR is an exteroceptive-nociceptive reflex recorded on the orbicularis oculi muscle and formed by three components: the two principal ones, R1 and R2, of well-known characteristics, and a third, R3, of increasing interest, to which there is wide mention. The trigeminal afferent limb reaches the facial efferent one by means of a long and quite complex central pathway located at the brainstem bulbopontine level. The anatomical substrate and criteria of the rich topographical lesional semiology of the BR are established. The importance of the suprasegmental influences upon the reflex, coming mainly from the cerebral cortex and basal ganglia, as well as the impairment caused by their damage, will be emphasised. Special attention is paid to the relationship between the reflex and the dopaminergic system, and the consequences of its derangement. The methods of habituation and suppression-recovery of the BR are extensively and critically reviewed. These methods measure its excitability and serve in practice for the pathophysiological study of numerous diseases. The relationship of the BR with the spontaneous blinking is considered, and the existence of a primary inhibitory reflex on levator palpebrae muscles, previous to the active reflex response of the orbicularis, is proposed. The electrophysiological characteristics of the glabellar reflex, the corneal reflex, the acoustic, photic and somatosensory provoked BR, the ontogeny, and some of the common factors influencing the reflex, such as sleep, are also discussed. The strategic position of the neural structures of the BR, in an area involved in the gating of the various sensory-motor systems and the relative ease to its evaluation with common methodology used in clinical neurophysiology, makes the BR an essential tool for the diagnosis and pathophysiological insight into an important number of human neurological disorders.
Animals↗
The Bezold reflex: a special case of the left ventricular mechanoreceptor reflex.
Our previous finding that increasing myocardial contractility caused reflex systemic hypotension, the left ventricular (LV) mechanoreceptor reflex, suggested that the classical Bezold reflex (systemic hypotension and bradycardia after intracoronary administration of veratrum alkaloids) may be initiated by these same LV mechanoreceptors. In our working LV preparation with the coronary and systemic circulations isolated and perfused separately, intracoronary injection of veratrum alkaloids, like that of catecholamines or ouabain, had a positive inotropic effect which produced the hypotensive response typical of the LV mechanoreceptor reflex. To test directly if veratridine's positive inotropic effect initiates the Bezold reflex, verapamil, which blocks the slow Ca(2+) channels of myocardial cells but leaves intracardiac nerves unaffected, was injected by the intracoronary route to prevent the increased contractility from intracoronary injection of veratridine which also abolished the reflex hypotension, demonstrating conclusively that increasing myocardial contractility and thereby activating LV mechanoreceptors but not chemoreceptors initiates the Bezold reflex. Contrariwise, decreasing contractility or cardiac asystole by administration of tetrodotoxin, verapamil, or EDTA resulted in an increase in the systemic resistance, indicating that changes in the magnitude of the stimulus initiating the LV mechanoreceptor reflex (i.e., changes in myocardial contractility) lead to directionally opposite changes in peripheral resistance, as in the sino-aortic mechanoreflexes. Thus, it is concluded that the Bezold reflex is a special case of the LV mechanoreceptor reflex. The latter, by means of feedback mechanisms, functions normally by continuously matching the peripheral resistance to the LV contractile state so as to maintain the arterial pressure constant, thereby playing an important role in blood pressure regulation.
Animals↗
Leg muscle reflexes mediated by cutaneous A-beta fibres are normal during gait in reflex sympathetic dystrophy.
OBJECTIVES: Reflex sympathetic dystrophy (RSD) is, from the onset, characterized by various neurological deficits such as an alteration of sensation and a decrease in muscle strength. We investigated if afferent A-beta fibre-mediated reflexes are changed in lower extremities affected by acute RSD. METHODS: The involvement of these fibres was determined by analyzing reflex responses from the tibialis anterior (TA) and biceps femoris (BF) muscles after electrical stimulation of the sural nerve. The reflexes were studied during walking on a treadmill to investigate whether the abnormalities in gait of the patients were related either to abnormal amplitudes or deficient phase-dependent modulation of reflexes. In 5 patients with acute RSD of the leg and 5 healthy volunteers these reflex responses were determined during the early and late swing phase of the step cycle. RESULTS: No significant difference was found between the RSD and the volunteers. During early swing the mean amplitude of the facilitatory P2 responses in BF and TA increased as a function of stimulus intensity (1.5, 2 and 2.5 times the perception threshold) in both groups. At end swing the same stimuli induced suppressive responses in TA. This phase-dependent reflex reversal from facilitation in early swing to suppression in late swing occurred equally in both groups. CONCLUSIONS: In the acute phase of RSD of the lower extremity there is no evidence for abnormal A-beta fibre-mediated reflexes or for defective regulation of such reflexes. This finding has implications for both the theory on RSD pathophysiology and RSD models, which are based on abnormal functioning of A-beta fibres.
Adult↗
Orbicularis oculi reflex in the Wallenberg syndrome: alteration of the late reflex by lesions of the spinal tract and nucleus of the trigeminal nerve.
The orbicularis oculi reflex was studied in nine cases with lateral medullary lesions. Diagnosis of the Wallenberg syndrome was made clinically in seven cases and at necropsy in another. The clinical features of one other case were closely allied to but not typical of this syndrome. An afferent delay of the late reflex on the side of the lesion in the presence of a normal early reflex was seen in all but two cases. In one of the latter, the late reflex was normal and in the other, a comatose patient, the late reflex was totally absent. It was concluded that the neurones of the first order responsible for the bilateral late reflex on unilateral stimulation terminate in the ipsilateral spinal nucleus of the trigeminal nerve without significant crossing over to the same structure on the other side. An afferent delay of the late reflex in the presence of a normal or nearly normal early reflex is consistent with a lateral medullary lesion implicating the spinal tract and nucleus. The Wallenberg syndrome is a common clinical entity showing this abnormality of the orbicularis oculi reflex.
Adult↗
Long latency cutaneous reflex effect on H-reflex recovery in hemiplegics and paraplegics: a longitudinal study for the assessment of motor function.
H-reflex recovery by twin pulses was recorded serially in 10 paraplegics for 5 months and in 23 hemiplegics for 2 months after the lesion. Fifty-one normal subjects acted as controls. The effect of cutaneous tactile stimulation was also studied simultaneously by applying electrical stimuli synchronized with twin pulses to the skin over the lateral border of small toe. In paraplegics, the H-reflex recovery curves recorded serially showed a highly depressed pattern during the first two weeks, an almost normal pattern during the second and third months and a significantly elevated pattern during the fourth and fifth months. Whereas cutaneous stimulation in control subjects produced a highly significant late inhibition of H-reflex recovery between 600 ms and 600 ms, in paraplegics it failed to produce any significant effect, except in two, who besides having a normal H-reflex recovery curve even during the first week, showed a substantial amount of cutaneous inhibition of H-reflex recovery, 4 months after the lesion. A highly depressed pattern of H-reflex recovery was observed on the affected side of the majority of hemiplegics during the first week after the lesion, many of them showing similar pattern on the "unaffected side" also. The serial study showed very good improvement in all hemiplegics both in terms of H-reflex recovery pattern and the amount of cutaneous inhibition. The observations in present study suggest preservation and/or restoration of supraspinal influences in many hemiplegics and in at least two paraplegics. The study also shows that a serial recording of H-reflex recovery curve and the amount of cutaneous reflex effect on it, is a very sensitive method of assessing the supraspinal influences on the spinal motoneurones and so can be of immense help in the diagnosis and prognosis in hemiplegics and paraplegics.
Female↗
Reflex and non-reflex torque responses to stretch of the human knee extensors.
Reflex responses to unexpected stretches are well documented for selected muscles in both animal and human. Moreover, investigations of their possible functional significance have revealed that stretch reflexes can contribute substantially to the overall stiffness of a joint. In the lower extremity only the muscles spanning the human ankle joint have been investigated in the past. This study implemented a unique hydraulic actuator to study the contributions of the knee extensor stretch reflex to the overall knee joint torque. The quadriceps muscles were stretched at various background torques, produced either voluntarily or by electrical stimulation, and thus the purely reflex mediated torque could be calculated. The stretch had a velocity of 67 degrees /s and an amplitude of 20 degrees. A reflex response as measured by electromyography (EMG) was observed in all knee extensors at latencies of 26 - 36 ms. Both phasic and tonic EMG stretch responses increased with increasing background torques. Lines of best fit produced correlation coefficients of 0.59 - 0.78. This study is the first to examine the reflex contribution of the knee extensors to the total torque at background torques of 0 - 90% MVC. The contribution of the reflex mediated torque is initially low and peaked at background torques of 20 - 40% MVC. In terms of the total torque the reflex contributed 16 - 52% across all levels of background torque. It is concluded that during medium background torque levels such as those obtained during walking, the stretch reflex of the quadriceps muscle group contributes substantially to the total torque around the knee joint.
Adult↗
Labyrinth and neck reflex modification of the tonic vibration reflex in the decerebrate cat.
The interaction between tonic labyrinth or neck reflexes and the tonic vibration reflex acting on the medial head of triceps in the decerebrate cat is described. Medial triceps was isotonically loaded and reflex actions were measured as changes in muscle length. Natural stimulation of the receptors giving rise to tonic labyrinth or neck reflexes can either enhance or diminish the size of a pre-existing tonic vibration reflex. It is also shown that descending activity from either the labyrinth or neck reflex systems can completely suppress the tonic vibration reflex, whereas the tonic vibration reflex was never observed to suppress an established labyrinth or neck reflex.
Animals↗