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PubMed1984

The significance of proprioception on postural stabilization as assessed by ischemia.

In order to further investigate the role of proprioceptive input from the legs for the maintenance of upright human posture ischemia was bilaterally applied at the level of the ankle or the thigh. Preservation of efferent innervation was ascertained by measurements of the maximal force of voluntary dorsi- and plantarflexion. Visual stabilization was excluded by eye closure. To test different frequency domains of postural stabilization, subjects were exposed to sudden ramp tilts or to sinusoidal low frequency (0.3 Hz) anteriorposterior displacements of the supporting platform. The results indicate that proprioceptive input from skin, pressure and joint receptors of the foot (ischemia at the ankle) is of minor importance for the compensation of rapid displacements, but plays a significant role when the platform moves at low frequencies. M1 and M2 responses in the stretched triceps surae and the late antagonistic response of the anterior tibial muscle (M3) are preserved with ischemia of the foot. Reversible ischemic paralysis or other (yet unidentified) mechanisms of destabilization must be responsible for the severe decrease of postural stability observed with ischemia at the level of the thigh and sinusoidal platform movements. Complete loss of the proprioceptive input from the legs leads to a pathognomonic 1Hz body tremor both under static and dynamic conditions.

Electromyography↗
PubMed1991

Clinical signs in severe Guillain-Barré syndrome: analysis of 63 patients.

Clinical data are presented of 63 artificially ventilated Guillain-Barré patients. About half of them had an antecedent event. In 57% the disease was heralded by sensory symptoms. The mean progressive phase lasted 12 days, the plateau 12 days and the recovery phase 568 days. In all patients one or more cranial nerves were involved, most often leading to facial palsy or difficulties in swallowing. Three-quarters of the patients had sensory signs, proprioceptive more often than superficial. Autonomic disturbances were common, especially hypertension and tachycardia. Twenty-two percent of the patients were severely confused in the first weeks of the disease. Laboratory examination showed atypical lymphocytes in the blood of 37% of patients and disturbed hepatic function tests in 79%. CSF protein level was elevated in all patients, with a mean value of 1.5 g/l.

Adolescent↗
PubMed1995

A critical examination of the Moro response in newborn infants--symmetry, state relation, underlying mechanisms.

The primary purpose of the present study was to analyze quantitatively the vestibular evoked Moro response, and the symmetry of the movement pattern involved, as the traditional descriptions bring about. Another aim was to determine the segmental movements involved and determine whether the components of the Moro response are dependent on changes in the infant's behavioral state. Another question concerns whether the form of these movements changed over repeated trials on the same day, or from the first to the fifth day after birth. Vestibular evoked Moro responses of 52 neonates, 1-5 days of age, elicited in different behavior states (State 1-5), were examined and quantitatively analyzed. The response was evoked by a predefined, rapid, downward, vertical body motion, without any dorsiflexion of the infant's head. Optoelectronic device (SELSPOT II) were used to monitor the arm/hand movement patterns involved in the response. The three-dimensional movement pattern in space, duration, velocity, latency, and the acceleration of both arms/hands were analyzed in relation to the infant's behavioral state. The response movements were structured into phases of abduction/extension, adduction/flexion and the extension/flexion of the fingers. The vestibular stimulation used was found to be sufficient for eliciting an adequate Moro response. The segmental movement pattern of the Moro response was found to be sensitive to the infant's behavioral state at the time when the response was elicited. This was found in the movement pattern, duration, latency, and the velocity of the response. The response was found to be asymmetrical, in 82% of the infants it was found to be a predominant shorter onset latency of the right arm, in 12% the opposite was found. These findings suggest that there is a fundamental, spinal asymmetry involved in the Moro response which is subject to supraspinal influences emanating from the vestibulospinal system. No differences were found between 1 and 5 days of age for any of the scoring categories, and no differences were found within groups over six successive trials.

Aging↗
PubMed1975

Cystometry. V. Bladder sensation.

Bladder sensation is an important variable in cystometry. Sensory complaints are a valuable portion of the history which may be further defined and documented by the cystometric examination.

Animals↗
PubMed1981

Some contributions of touch, pressure and kinesthesis to human spatial orientation and oculomotor control.

Human spatial orientation and oculomotor control are under multimodal influence. It is not possible in the normal animal to stimulate differentially the vestibular receptors without activating other receptor systems whose activity may have a profound influence on postural control and experienced orientation. Many patterns of behavior and response that have been attributed solely to vestibular function are actually dependent wholly or in part on touch, kinesthetic, and proprioceptive stimulation.

Eye Movements↗
PubMed1991

The pathway from Ia forelimb afferents to the motor cortex: a new hypothesis.

Forelimb target-reaching and food-taking in cats depend on different interneuronal circuitry in the spinal cord. On the basis of previous findings regarding the effect of transection of the corticospinal tract in the spinal cord, of high dorsal column (DC) transection, of low pyramidotomy and of pyramidotomy after previous DC transection, it is proposed that the food-taking movement is temporally linked to target-reaching as follows: During target-reaching, the position of the paw is signalled by the pathway from forelimb proprioceptors (mainly Ia) to the motor cortex with a relay in the main cuneate nucleus. The command for food-taking is issued by the motor cortex only when the pathway from the forelimb signals that the paw approaches the target correctly, as may be determined by a comparison of the information from the forelimb with an efference copy of the motor program for target-reaching. The hypothesis is based on previous results regarding the organization of the pathway from the forelimb to area 3a and the motor cortex, and regarding the cortico-cuneate pathway with selective projection from area 3a and motor cortex to the basal caudal part of the cuneate nucleus, where the proprioceptive information from the forelimb is relayed. Results relevant to the present hypothesis regarding responses of precentral neurones during active and passive movements in awake animals are briefly discussed.

Animals↗
PubMed1986

Effects of rectilinear acceleration, caloric and optokinetic stimulation of human subjects in the Spacelab D-1 mission.

A set of vestibular experiments was performed during the course of the German Spacelab D-1 mission from 30 October to 6 November 1985 by a consortium of experimenters from various european countries. Similar to the Spacelab SL-1 mission all of the scientific crew members were theoretically and practically trained for the experiments. Baseline measurements for all tests were collected 113, 86, 44, 30 and 18 days prior to the mission and compared with data taken inflight, on the landing day and the consecutive 7 to 14 days. The hardware comprised mainly a motordriven accelerating platform, the SPACE SLED, and the vestibular helmet, a multi-purpose instrument in support of a variety of vestibular experiments including air-calorisation of the ears, optokinetic stimulation pattern presentation and optical and nystagmographic recording of eye movements. Measurements of the threshold for the perception of detection of whole body movement did not reveal any dramatic changes in the 2 measured axes inflight when compared to preflight values. Early postflight values show a significantly elevated threshold for all axes in 3 out of 4 subjects. The caloric nystagmus, already found during the SL-1 mission, was confirmed on all three tested subjects during the D-1 mission. It's amplitude and in some instances it's direction were influenced by horizontal acceleration on the SLED. The amplitude of optokinetic nystagmus increased when subjects were allowed to free-float over that seen when subjects were fixed. Stimulation of the neck receptors by roll movements of the body against the fixated head resulted in illusory object motion to the contralateral side. Torsional movements of the eyes during such neck receptor stimulation was present inflight and postflight, while it had not been observed preflight. Most results point to a reduction of otolithic effects in favour of visual and proprioceptive influences for spatial orientation.

Acceleration↗
PubMed1988

Afferent signals from cat extraocular muscles in the medial vestibular nucleus, the nucleus praepositus hypoglossi and adjacent brainstem structures.

The responses of single units in the vestibular nuclei, nucleus praepositus hypoglossi and in the brainstem, deep and posterior to the abducens nucleus, were studied in anaesthetized, paralysed cats. Natural vestibular stimulation was provided by horizontal, sinusoidal oscillation of the animal and extraocular muscle afferents of the ipsilateral eye were activated either by passive eye-movement or by electrical stimulation of the inferior oblique branch of the oculomotor nerve in the orbit. Unit responses to vestibular and/or orbital stimuli were examined in sets of peristimulus time histograms interleaved in time. Of 127 units exposed to both types of stimulus, 40 (32%) responded only to vestibular input; 46 (32%) were affected only by the orbital afferent signal and 19 (15%) received both signals; the remaining 22 units (17%) were discarded because they had polymodal (usually somaesthetic) input. Of the 93 units whose recording sites were determined histologically, 24 were in the medial vestibular nucleus, 16 in the n. praepositus hypoglossi and 45 in the magnocellular nucleus of the reticular formation posterior and deep to the abducens nucleus. In these three nuclei 19 units in total were found which carried the orbital proprioceptive afferent signal and also responded to horizontal vestibular stimulation. The input from the eye muscles proved able to modify the vestibular response by adding excitation or inhibition or both. Effects of the orbital signal were generally phasic. About half of the units which responded to passive eye-movement showed statistically significant differences between their responses to horizontal and to vertical eye-movement. We have shown previously that signals from extraocular muscle proprioceptors reach the vestibulo-oculomotor system in an amphibian and a bony fish; the present experiments show that this is the case in a mammal also. The fact that the visual and visuomotor behaviour of these three species is very different suggests that the proprioceptive signal may play some rather fundamental role in the vestibulo-ocular system. The principal interest of the present results is that they demonstrate that units in the central vestibular system of the cat, in structures which are known to be concerned in oculomotor control, and particularly in the organization of horizontal eye-movement, receive an afferent signal from the eye muscles during passive eye-movement. These brainstem nuclei are known to receive various combinations of input from the vestibular and visual systems and of signals which represent neck movement and eye position and velocity.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗