Recruitment order of motor units on voluntary contraction: changes induced by proprioceptive afferent activity.
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Action Potentials↗
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Results for “REFLEX, PROPRIOCEPTIVE”
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[Proprioceptive regulation of the autonomic function of the skin].
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Autonomic Nervous System↗
Vestibular-proprioceptive functions in 4 year olds: normative and regression analyses.
Normative data were obtained for 156 pre-school children's performances on measures of muscle tone, muscle co-contraction, standing balance, prone extension posture, flexion supine posture, asymmetrical tonic neck reflex, and postrotary nystagmus. Regression analysis indicated that these combined variables accounted for only 13.5 percent of the variance of postrotary nystagmus of 145 four year olds. However, if the data are examined only for children exhibiting nystagmus that is lower than 1 standard deviation below the mean, then these variables account for 50 percent of the variance of nystagmus. Prone extension posture, standing balance-eyes closed, and muscle tone account for 37 percent of the variance within this low-nystagmus population. These results are considered in light of the authors' previous studies demonstrating that, in learning-disabled children, vestibular-proprioceptive measures can be used clinically to predict which children will respond to sensory integration therapy with changes in postrotary nystagmus. These changes, according to sensory integration theory, reflect positive responses to therapy.
Child, Preschool↗
Distribution of NADPH diaphorase-exhibiting primary afferent neurons in the trigeminal ganglion and mesencephalic trigeminal nucleus of the rabbit.
1. Nitric oxide (NO) is highly reactive gaseous molecule to which many physiological and pathological functions have been attributed in the central (CNS) and peripheral (PNS) nervous system. The present investigation was undertaken to map the distribution pattern of the enzyme responsible for the synthesis of NO, nitric oxide synthase (NOS), and especially its neuronal isoform (nNOS) in the population of primary afferent neurons of the trigeminal ganglion (TG) and mesencephalic trigeminal nucleus (MTN) of the rabbit. 2. In order to identify neuronal structures expressing nNOS we applied histochemistry to its specific histochemical marker nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd). 3. We found noticeable amount of NADPHd-exhibiting primary afferent neurons in TG of the rabbit under physiological conditions. The intensity of the histochemical reaction was highly variable reaching the maximum in the subpopulation of small-to-medium-sized neurons. The large-sized neurons were only weakly stained or actually did not posses any NADPHd-activity. In addition, NADPHd-positive nerve fibers were detected between clusters of the ganglionic cells and in the peripheral branches of the trigeminal nerve (TN). NADPHd-exhibiting MTN neurons were noticed in the whole rostrocaudal extent of the nucleus even though some differences were found concerning the ratio of NADPHd-positive versus NADPHd-negative cell bodies. Similarly, we observed striking diversity in the intensity of NADPHd histochemical reaction in the subpopulations of small-, medium-, and large-sized MTN neurons. 4. The predominant localization of NADPHd in the subpopulation of small-to-medium-sized TG neurons which are generally considered to be nociceptive suggests that NO probably takes part in the modulation of nociceptive inputs from the head and face. Furthermore, we tentatively assume that NADPHd-exhibiting MTN neurons probably participate in transmission and modulation of the proprioceptive impulses from muscle spindles of the masticatory muscles and mechanoreceptors of the periodontal ligaments and thus provide sensory feedback of the masticatory reflex arc.
Animals↗
Sensory interaction testing in platform posturography.
Mostly techniques measuring the vestibulo-ocular reflex (VOR) have been used for the evaluation of patients with dizziness problems. Some investigators, however, have also tried to take into account the vestibulospinal reflex (VSR). So recording techniques for the Romberg-test have been proposed and called posturography (PG). By interfering with the visual and proprioceptive sensory inputs during this PG-testing one tries to find out how 'sensory interaction' is organized in the balance performance of the patient examined. To interfere with vision, closure of the eyes has been commonly used and to interfere with proprioception, the patient can be put on foam-rubber, which makes the contribution of the foot-ankle proprioception less adequate. These interferences are applied once separately and once combined. The degree of 'abnormality' is assessed by a score-system for parameters surface (S) and velocity (V), which measure the postural sway. A comparison of tests with and without influence on the sensory inputs gives an idea of the sensory interaction. Patients with peripheral vestibular disorders were examined: patients with BPPV, with spontaneous vertigo attacks and with a sudden vestibular deficit. When applying this evaluation technique different formulae or patterns can be found. Firstly complete normal evaluation, which means that there is no influence of the vestibular disturbance upon the PG results. Secondly a normal balance when using all available sensory information, but disturbed balance as soon as one of the sensory inputs is influenced by the test conditions. Thirdly striking destabilization when closing the eyes. Fourthly striking destabilization when misleading the ankle and foot proprioceptor.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Patients with horizontal gaze palsy and progressive scoliosis due to ROBO3 E319K mutation have both uncrossed and crossed central nervous system pathways and perform normally on neuropsychological testing.
BACKGROUND: Horizontal gaze palsy and progressive scoliosis (HGPPS) is caused by mutations of the ROBO3 gene, which encodes a receptor associated with axonal guidance during development. Although there is evidence for uncrossed cuneatal and corticospinal tracts in HGPPS, it is unclear whether other central nervous system pathways are involved. OBJECTIVE: To study two patients with HGPPS homozygotic for the ROBO3 E319K mutation using a variety of neurophysiological and neuropsychological tests. METHODS: A battery of neuropsychological tests was applied to assess various cognitive and perceptual functions. The corticospinal, somatosensory and auditory pathways were evaluated using appropriate neurophysiological tests. To access motor pathways to the neck muscles, electromyographic recordings were obtained from the sternocleidomastoideus and splenius capitis muscle during active head rotation. RESULTS: Both patients performed normally on manual dexterity, complex sensory and visuospatial functions, reading and general intelligence tests. Motor evoked potentials in both patients showed uncrossed corticospinal tracts for the extremities, although in one patient, electromyography indicated pyramidal tract crossing for the neck muscles. Although somatosensory evoked potentials showed uncrossed somatosensory fibres subserving proprioception and light touch, right median nerve somatosensory evoked potential in one patient indicated a partial lemniscal crossing. Sympathetic skin response and blink reflex showed a midline crossing of the spinothalamic and quintothalamic tracts. Brain stem auditory evoked potentials indicated a lack of crossing in the level of the trapezoid body. CONCLUSIONS: Our patients with the ROBO3 E319Kappa mutation show normal perceptual and cognitive functions and have both crossed and uncrossed motor, sensory and auditory pathways.
Cognition↗
Jaw-muscle spindle afferent pathways to the trigeminal motor nucleus in the rat.
Neural pathways conveying proprioceptive feedback from the jaw muscles were studied in rats by combining retrograde and intracellular neuronal labeling. Initially, horseradish peroxidase was iontophoresed unilaterally into the trigeminal motor nucleus (Vmo). Two days later, 1-5 jaw-muscle spindle afferent axons located in the mesencephalic trigeminal nucleus were physiologically identified and intracellularly stained with biotinamide. Stained mesencephalic trigeminal jaw-muscle spindle afferent axon collaterals and boutons were predominantly distributed in the supratrigeminal region (Vsup), Vmo, dorsomedial trigeminal principal sensory nucleus (Vpdm), parvicellular reticular formation (PCRt), alpha division of the parvicellular reticular formation (PCRtA), and dorsomedial portions of the spinal trigeminal subnuclei oralis (Vodm), and interpolaris (Vidm). Numerous neurons retrogradely labeled with horseradish peroxidase from the trigeminal motor nucleus were found bilaterally in the PCRt, PCRtA, Vodm, and Vidm. Retrogradely labeled neurons were also present contralaterally in the Vsup, Vpdm, Vmo, peritrigeminal zone, and bilaterally in the dorsal medullary reticular field. Putative contacts between intracellularly stained mesencephalic trigeminal jaw-muscle spindle afferent boutons and trigeminal premotor neurons retrogradely labeled with horseradish peroxidase were found in the ipsilateral Vodm, PCRtA, and PCRt, as well as the contralateral Vsup, Vmo, Vodm, PCRt, and PCRtA. Thus, multiple disynaptic jaw-muscle spindle afferent-motoneuron circuits exist. These pathways are likely to convey long-latency jaw-muscle stretch reflexes and may contribute to stiffness regulation of the masticatory muscles.
Afferent Pathways↗
Scoliosis induced by medullary damage: an experimental study in rabbits.
To date, there have been no reports of experiments designed to induce scoliosis by direct damage of different areas of the spinal cord. In a series of rabbits with medullary damage, the authors attempted selectively to interrupt the pathways that mediate proprioceptive input. Unilateral lesion of the dorsal column and posterior horn of the spinal cord was performed using three different techniques: coagulation with laser, stereotaxic microcoagulation, and longitudinal electrocoagulation. Of 32 operated rabbits, 17 developed scoliosis, exhibiting clear pathologic damage of the spinal cord. Electrophysiologic study, including EMG and analysis of the tonic -- vibratory reflex, was performed on 10 rabbits with medullary damage (scoliotic and non-scoliotic) and 12 matched controls. The data suggest disturbance of the sensory afferences that control the postural tone and consequent muscular imbalance, expressed as reduced activity in the muscles of the convex side. This work supports the view that loss of proprioceptive neural impulses caused by medullary damage can induce scoliosis.
Animals↗
Long-latency stretch reflex induced by tendon jerk in human triceps brachii muscle.
The electrical activity of the human triceps brachii muscle was recorded with surface electrodes in 14 healthy volunteers. Three experimental conditions were used to analyze muscle responses produced by tendon tap with an electromechanical hammer: 1) the muscle was at rest, 2) the subjects maintained an isometric tension for constant background EMG activity and 3) the subjects were asked to extend their arm in response to an acoustic signal occurring simultaneously with the tap. The analyses were performed with a computer. The monosynaptic tendon reflex had a mean latency of 12,5 ms. Later responses were observed with a mean latency of 62.8 ms. The later response observed in the extension experiments showed a synchronous EMG activity in comparison to the voluntary activity. It seems likely that proprioceptive impulses are of major importance in producing also the late responses since the method used minimalized cutaneous and joint afferent inputs.
Adolescent↗
Non-invasive technique for examining the respiratory proprioceptor system in man.
Our technique enables non-invasive experiments to be conducted on the proprioceptor part of respiratory control, while eliminating misleading responses due to interaction with the chemoreceptor system; interaction was prevented by stabilizing arterial PO2 and PCO2 with the aid of an optimal regulator based on a mini-computer which controlled the inspired gas mixture. The proprioceptor system in a human was disturbed by applying positive pressure pulses at the mouth, responses were derived from continuous air-flow measurement. The classical inflation inhibiting reflex and an effect akin to Head's paradoxical reflex were demonstrated.
Biomedical Engineering↗
The effect of a simulated knee joint effusion on postural control in healthy subjects.
OBJECTIVE: To determine the effects of a simulated knee joint effusion on center of pressure (COP) path and mean power frequency (MPF) during standing. DESIGN: Quasi-experimental design. SETTING: Sports injury research laboratory in a university setting. PARTICIPANTS: Twenty healthy volunteers, 10 of whom (age, 20.1+/-2.4y; height, 168.0+/-8.1cm; weight, 70.4+/-13.3kg) were assigned to an effusion group and 10 of whom (age, 25+/-3.8y; height, 169.4+/-8.9cm; weight, 74.7+/-7.7kg) were assigned to a control group. INTERVENTIONS: COP data were collected before and after a 60-mL injection of sterile saline into the knee joint space. MAIN OUTCOME MEASURES: COP path and mediolateral and anteroposterior MPF. RESULTS: COP path decreased after the effusion (pre-effusion mean, 92.2+/-21.9cm; posteffusion mean, 77.27+/-23.0cm). No change was found within the control group for COP path (P>.05). No differences were detected before or after joint effusion when the MPF was examined (P>.05). CONCLUSIONS: Possible explanations for the improved postural control after the effusion include additional somatosensory feedback, an augmented neural drive to the soleus, and/or increased capsular tension.
Adult↗
Laufband locomotion with body weight support improved walking in persons with severe spinal cord injuries.
After low transection of the spinal cord mammalian quadrupeds can be trained to walk on a driven surface indicating that coordinating neuronal circuits persist in the spinal cord segments caudal to the lesion. We trained 8 persons with incomplete spinal cord lesion on a Laufband (driven treadmill) for 1 1/2 to 7 months (5 days a week, 30-60 minutes daily) starting 5 to 20 months after injury and found significant improvement in the utilisation of the paralysed limbs during locomotion. Locomotion is described in one additional patient who had trained independently on parallel bars for several years. Five patients had complete functional paralysis in one lower limb when tested in a resting position. In EMG recordings voluntary activity (ie activity induced upon command) was absent or residual in the main flexor and extensor muscles of this limb. In contrast, during locomotion flexion and extension movements were performed and phasic EMG activity was present. In these 5 patients, and in all others reported here, skin sensibility and proprioception are preserved to different degrees in all limbs. In the course of locomotive training of 4 severely paralysed patients the initially habituating flexion reflexes could be entrained in the paralysed limbs as was the case for knee extension during stance. Subsequently, initial body weight support (BWS) of 40% could be reduced to 0%. The distance covered on the Laufband (0-104 m in the first week) increased significantly (200-410 m) in the last week of training as did speed (0-10 to 14-23 m/min). More importantly, this training subsequently allowed patients to walk on a static surface for 100 to 200 meters while voluntary activity remained absent in the paralysed limb when tested at rest. Similar progress was achieved in the 4 less severely paralysed patients. The one patient who had trained independently on parallel bars for several years is described walking on a static surface for 40 meters with the help of a walker, though he had one completely and one near completely paralysed lower limb. It appears that bipedal stepping with consequent knee extension and stabilisation can be taught after unilateral complete or near complete loss of voluntary activity, suggesting the manifestation of complex reflex motor patterns at the spinal level.
Adult↗
[The proprioceptive analyzer as the integrator of the motor activity. I. The structure and function].
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Humans↗
[The effect of curare-like agents on synaptic transmission in the spinal cord].
In experiments with decerebrated cats subject to study was the influence of new curare-like agents of non-depolarized type of action, such as diadonium, decadonium, RGH-1106, pancuronium-bromide (pavulon) and also of paramion and mellictine on the magnitude of mono-and polysynaptic potentials of the spinal cord, the time of synaptic delay, the lability of the spinal centres and cycle of the motoneurons excitability restoration. Diadonium, decadonium, RGH-1106 and pavulon when used in 1--5-fold myoparalytic doses did not affect the bioelectric activity of the spinal cord. Mellictinum (3,5--4,5 mg/kg)) produced a rise of the monosynaptic responses amplitude by 21 per cent through inhibition of the Renshow n-cholinoreceptors cells. Paramion (0.3--1 mg/kg) suppressed monosynaptic potentials, increasing the afferent proprioceptic activity.
Animals↗
[Complex perception of stimuli during conditioning].
The review concerns the effects of a variety of stimuli on the reproduction of conditioned reflexes. By the literature data, during conditioning of any type, besides the single stimulus intentionally applied by an experimenter as a conditioned one, an animal perceives the whole complex of stimuli (acoustic, visual, olfactory, algesic, and other exteroceptive, proprioceptive, and interoceptive stimuli), including those of the environment and time of the day during training. Many of these stimuli are essential for the reproduction of the acquired habit. The complex of stimuli that act on an animal during the reproduction should in all parameters correspond to that perceived by the animal during training. If the complexes differ at least in one stimulus, the reproduction of the reflex may fail.
Animals↗
Impairments of reaching movements in patients without proprioception. I. Spatial errors.
1. This paper introduces a series of studies in which we analyze the impairments in a planar reaching task in human patients with severe proprioceptive deficits resulting from large-fiber sensory neuropathy. We studied three patients, all of whom showed absence of discriminative tactile sensation, position sense, and stretch reflexes in the upper extremities. Muscle strength was normal. We compared the reaching movements of the patients with those of normal control subjects. The purpose of this first paper was no characterize the spatial errors in these patients that result primarily from impairments in the planning and execution of movement rather than in feedback control. This was done by using a task in which visual feedback of errors during movement was prevented. 2. Subjects were instructed to move their hand from given starting positions of different targets on a horizontal digitizing tablet. Hand position and targets were displayed on a computer screen. Subjects could not see their hand, and the screen display of hand position was blanked at the signal to move. Thus visual feedback during movement could not be used to achieve accuracy. Movement paths were displayed as knowledge of results after each trial. 3. Compared with controls, the patients made large spatial errors in both movement direction and extent. Directional errors were evident from movement onset, suggesting that they resulted from improper planning. In addition, patients' hand paths showed large curves and secondary movements after initial stops. 4. The overall control strategy used by patients appeared the same as that used by controls. Hand trajectories were approximately bell shaped, and movement extent was controlled by scaling a trajectory waveform in amplitude and time. However, both control subjects and patients showed systematic errors in movement extent that depended on the direction of hand movement. In control subjects, these systematic dependencies of extent on direction were small, but in patients they produced large and prominent errors. Analysis of the hand trajectories revealed that errors were associated with differences in velocity and acceleration for movements in different directions. In an earlier study, we showed that in subjects with normal sensation that the dependence of acceleration and velocity on direction results from a failure to take the inertial properties of the limb into account in programming the initial trajectory. In control subjects, these differences in initial acceleration are partially compensated by direction-dependent variations in movement time.(ABSTRACT TRUNCATED AT 400 WORDS)
Adult↗
Traumatic atypical Brown-Sequard syndrome: case report and literature review.
A man was kicked on the neck, 10 days after which he noted right-sided numbness. Clinically, he had diminished deep tendon reflexes over the left upper limb, absent left superficial abdominal reflexes, a left extensor plantar response, mild left hemiparesis, diminished pinprick, temperature and vibratory sensation up to the right T(4-5) dermatome and diminished proprioceptive sensation in the right upper and lower limbs. Cervicothoracic magnetic resonance imaging (MRI) revealed a left C(6-7) posterolateral disc prolapse with indentation and oedema of the cord at the same level. He was given intravenous dexamethasone, with mild resolution of his motor but not his sensory symptoms. Transcranial magnetic stimulation and evoked potentials performed 3 days later were unremarkable. He was discharged soon after, preferring to seek traditional therapy in his country. We attempt to explain the anatomical basis for his clinical signs, review the literature for similar cases, and examine the usefulness of available treatment and investigations.
Adult↗
Cervical vertigo. Diagnostic and semiological problem with special emphasis upon "cervical nystagmus".
There is a strong evidence that vertigo can be produced by cervical disturbance, either via the neck-proprioceptor, or via the vascular supply by the vertebral artery. However, it is very difficult to confirm the cervical origin of the vertigo in a particular patient. "Cervical nystagmus" has been proposed as a diagnostic clue. But critical analysis, discussed in this paper, has raised doubt about its reliability. The most know type, the neck torsion nystagmus, appears to be in fact a "normal" cervico-ocular reflex. Its inconstancy and low gain makes that it is only present in 50% of the subjects. Reduced vestibular input as well as enhanced cervical proprioceptive input favour its appearance. In this way the presence of NTN is suggestive for a cervical component but doesn't mean that the vertigo is cervical. Correlation with other cervical data is needed to conclude to a "cervical component" in the vertigo.
Humans↗