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PubMed2002

Separation and estimation of muscle spindle and tension receptor populations by vibration of the biceps muscle in the frog.

Frog spinal cord reflex behaviors have been used to test the idea of spinal primitives. We have suggested a significant role for proprioception in regulation of primitives. However the in vivo behavior of spindle and golgi tendon receptors in frogs in response to vibration are not well described and the proportions of these proprioceptors are not established. In this study, we examine the selectivity of muscle vibration in the spinal frog. The aim of the study was (1) to examine how hindlimb muscle spindles and GTO receptors are activated by muscle vibration and (2) to estimate the relative numbers of GTO receptors and spindle afferents in a selected muscle, for comparison with the mammal. Single muscle afferents from the biceps muscle were identified in the dorsal roots. These were tested in response to biceps vibration, intramuscular stimulation and biceps nerve stimulation. Biceps units were categorized into two types: First, spindle afferents which had a high conduction velocity (approximately 20-30 m/s), responded reliably (were entrained 1:1) to muscle vibration, and exhibited distinct pauses to shortening muscle contractions. Second, golgi tendon organ afferents, which had a lower conduction velocity (approximately 10-20 m/s), responded less reliably to muscle vibration at physiologic muscle lengths, but responded more reliably at extended lengths or with background muscle contraction, and exhibited distinct bursts to shortening muscle contractions. Vibration responses of these units were tested with and without muscle curarization. Ensemble (suction electrode) recordings from the dorsal roots were used to provide rough estimates of the proportions of the two muscle afferent types.

Action Potentials↗
PubMed1979

[Electrophysiological study of cutaneous reflexes during avoidance reaction of the arms (author's transl)].

Electrophysiological studies of the cutaneous reflexes during avoidance reaction of the arms demonstrate more particularly the presence of facilitation of late reflex responses and stimultaneous activation of flexor and extensor muscles. The avoidance reaction is not the inverse electrophysiological image of pathological prehension, as it produces, at least in one of its aspects, a much more fundamental modification of the segmental reflex systems of muscle contraction regulation. This motor disorganization is rarely observed, and could result from a disequilibrium between proprioceptive sensitivity and skin sensitivity: the loss of proprioceptive control would facilitate contact reactions.

Aged↗
PubMed1976

[Functional posterior radiculotomy, in the treatment of cerebral spasticity. peroperative electric stimulation of posterior roots and its use in the choice of the roots to be sectioned].

The authors present a modification of Foerster's Rhizotomy for the treatment of spasticity in cerebral palsy: functional posterior rhizotomy. The selection of the roots/rootlesses to be sectioned, is accomplished on functional data, based upon the analysis of the reflex responses to the intraoperative lumbar dorsal roots stimulation. With this method it is possible to selectively interfere with the pathological circuits responsible for hypertonia, saving proprioceptive afferences necessary for motor reeducation. The clinical results on hypertonia are the same as for total or partial rhizotomies, but sides effects (ataxia, hypotonia) are considerably reduced.

Cerebral Palsy↗
PubMed1987

Pharmacological subtraction of the sensory controls over grasping in rats.

Catecholamine-depletion-induced catalepsy isolates and leaves intact an aggregate of allied reflexes (e.g., righting, standing still, bracing, and clinging) which involve all the body and limb segments in defending stable static equilibrium. Because other movement subsystems (locomotion, orienting, scanning, directed use of mouth or forepaws) are depressed, such animals cling in a vertical position for an abnormally long period of time. As a consequence, grasping reflexes may be studied independently of other responses. Haloperidol, a dopamine antagonist, abolishes visually elicited reaching and grasping, but leaves intact tactile and proprioceptive control of grasping. The grasping of haloperidol-treated rats can be further simplified by the pharmacological removal of the remaining sensory controls. The addition of morphine to haloperidol abolishes tactile grasping, while the addition of diazepam to haloperidol abolishes both tactile and proprioceptive (traction-elicited) grasping. Although visual, tactile, and proprioceptive grasping are abolished by haloperidol-plus-diazepam, some vestibular input to clinging remains: such rats, in response to being held vertically upright in the air, flex their digits with sufficient strength to allow them to cling vertically. The strength of forepaw digit flexion is severely diminished by labyrinthectomy, but the digits of the hindpaws appear to be unaffected. This residual non-labyrinthine digit gripping appears to be induced by proprioceptive inputs from the head, neck and torso in response to the vertical body position. Wrapping an elastic bandage snugly around the head and neck of a labyrinthectomized rat given haloperidol-plus-diazepam further diminishes the strength of forepaw digit flexion, and to a lesser degree hindpaw digit flexion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Reinnervated muscles fail to produce stretch reflexes.

1. We studied the stretch-evoked reflex organization of hind limb muscles in two decerebrate cats 36 mo after unilateral section and immediate surgical repair of the common nerve supplying the lateral gastrocnemius (LG) and soleus (S) muscles. 2. The production of considerable reflex force by reinnervated muscles in response to electrical stimulation of uninjured nerves indicated substantial functional recovery of motor units. However, reduction in the responsiveness of reinnervated muscles to stretch of the untreated medial gastrocnemius (MG) muscle indicated some deficit in recovery of normal synaptic integration. 3. Stretch failed to elicit autogenic excitation of the reinnervated S and LG. This failure was observed whether the reinnervated muscles were quiescent or contracting in other reflexes. 4. The heterogenic reflex organization of reinnervated muscles was abnormal. Stretch of the reinnervated S failed to evoke heterogenic reflexes both in the untreated MG and in the reinnervated LG. Stretch of the reinnervated LG failed to produce excitation of MG. 5. These findings demonstrate deficiencies in proprioceptive feedback from reinnervated muscles and lead us to expect incomplete recovery of motor function after nerve section.

Afferent Pathways↗
PubMed1987

Central projections of the mesencephalic nucleus of the fifth nerve: an autoradiographic study.

Projections of cells of the mesencephalic nucleus of the fifth nerve (Mes V) to brainstem structures in the cat were studied by labelling Mes V cells with tritiated leucine. Before the leucine injections were made, however, large kainic acid lesions were produced in the vicinity of Mes V cells because these neurons are resistant to being killed or injured by this neurotoxin. Thus Mes V cells were selectively labelled by the leucine even though they are scattered among many other neurons. Leucine injections near Mes V cells located in the mesencephalon, which are primarily the somata of jaw muscle spindle afferent fibers, produced essentially the same pattern of terminal labelling as injections near a caudally located group of Mes V cells that includes the somata of many tooth mechanoreceptive afferents. Labelling was dense above the trigeminal motor nucleus in the nucleus supratrigeminalis and in the most medial portion of the principal trigeminal sensory nucleus. A scattering of labelled axons and diffuse label was seen along the length of the tract of Probst, which follows the medial border of the descending trigeminal sensory nucleus as far caudally as the dorsal motor nucleus of the vagus. Labelling within most of the trigeminal motor nucleus, which is known to receive direct synaptic input from Mes V cells, was very light. The only reasonably dense region of label was confined to a small dorsolateral portion of the motor nucleus. Although Mes V has generally been supposed to be involved with jaw control in a direct, reflexive manner, the extensive projections to nucleus supratrigeminalis and parts of the trigeminal sensory system draw attention to the potential proprioceptive sensory contribution of Mes V.

Animals↗
PubMed2000

Functional recovery of paraplegic rats and motor axon regeneration in their spinal cords by olfactory ensheathing glia.

Axonal regeneration in the lesioned mammalian central nervous system is abortive, and this causes permanent disabilities in individuals with spinal cord injuries. In adult rats, olfactory ensheathing glia (OEG) transplants successfully led to functional and structural recovery after complete spinal cord transection. From 3 to 7 months post surgery, all OEG-transplanted animals recovered locomotor functions and sensorimotor reflexes. They presented voluntary hindlimb movements, they supported their body weight, and their hindlimbs responded to light skin contact and proprioceptive stimuli. In addition, relevant motor axons (corticospinal, raphespinal, and coeruleospinal) regenerated for long distances within caudal cord stumps. Therefore, OEG transplantation provides a useful repair strategy in adult mammals with traumatic spinal cord injuries. Our results with these cells could lead to new therapies for the treatment of spinal cord lesions in humans.

Animals↗
PubMed1975

[Prognostic elements at early stapes of severe spinal cord injuries (value of pain sensitivity].

The prognosis in serious spinal cord injury remains difficult. The neurologist has a large number of elements at his disposal, but their reliability is uncertain. Clinical information, experimental work and recent data on medullar vascularization makes it possible to isolate diagramatically in the spinal cord a medium layer which contains the pyramidal and spino-thalamic tracts. The neighbourhood of these two fasciculi confers them a similar vulnerability to severe injury. Thus when an injured tetraplegic or paraplegic patient recovers his sensitivity to pain, he finally must recover his motor function and on the contrary, the recovery of motility is impossible without a return of pain sens. Clinical observation is in consequence of major importance as it shows that the recovery of sensitivity to pain, in the case of a patient with a serious spinal cord injury, is an argument for a favourable prognosis, whereas the recovery of an isolated tact perception does not in itself makes it possible to hope for eventual recovery of motor power.

Adult↗
PubMed1987

[A case of acute sensory and autonomic neuropathy with regression].

The authors report the case of a 24 year old man with no previous disease who presented with a severe autonomic neuropathy. This included major gastrointestinal dysfunction characterised by decreased peristalsis without distension and paralysis of the gall bladder, and orthostatic hypotension with a normal cardiac tachycardia reflex. There was an associated sensory neuropathy affecting heat sensitivity without motor dysfunction and an increased CSF protein content. The proprioceptive nerve fibre conduction was decreased but another nerve conduction was normal initially. The mesenteric plexuses examined during sigmoidectomy performed for peritonitis due to multiple bowel perforations caused by fecoliths, showed no significant changes. Peripheral nerve biopsy revealed massive rarefaction of myelinated fibres which were of small diameter, and of the unmyelinated fibres, mainly due to axonal degeneration. Only two similar cases with incomplete recovery were found in the literature. In our case, a complete recovery was observed. The cause of the condition is unknown.

Acute Disease↗
PubMed1998

The human glenohumeral joint. A proprioceptive and stability alliance.

The glenohumeral joint, because of its relatively poor osseous and capsuloligamentous stability, depends upon the proprioceptive and stabilizing capabilities of musculotendinous structures more than any other joint in the human body. The purpose of this review is to compare the morphology, histology, and sensorimotor functional relationships of the human glenohumeral joint with the more abundant animal research data. From a synthesis of this information, a proprioceptive and stability alliance is proposed for the human glenohumeral joint which is initiated by mechanoreceptor activation from capsuloligamentous and musculotendinous structures, resulting in reflex-mediated protective muscular responses that are ultimately under the bias and sensitivity control of upper levels of the central nervous system hierarchy. The clinical impact of these findings as they relate to rehabilitation and conditioning strategies, surgical intervention, aging, and injury are discussed in addition to future research directions.

Aging↗
PubMed1990

Maturation of peripheral nerves in preterm infants. Motor and proprioceptive nerve conduction.

The peripheral nerve maturation (proprioceptive and motor nerve conduction velocities (PNCV and MNCV] was studied in 3 groups of newborn babies. Two groups of premature babies (PT), studied when they reached the expected date of birth (group I, gestational age (GA) at birth 27-31 weeks, n = 13, group II, GA at birth 32-35 weeks, n = 9), were compared to 10 normal full-term newborns (FT). The MNCV of PT babies was similar to that of FT babies: group I 22.8 +/- 3.3 m/sec (X +/- S.D.), group II 24.9 +/- 4.3 m/sec, FT 25.7 +/- 3.9 m/sec. PNCV was significantly lower in group I (18.1 +/- 5.9 m/sec) than in group II (28.3 +/- 6.4 m/sec) and in FT babies (32.0 +/- 7.4 m/sec) (P less than 0.001). Such a delay in maturation could be partly responsible for the neurological impairment often observed in PT babies.

H-Reflex↗
PubMed1991

Controlling the dynamics of a two-joined arm by central patterning and reflex-like processing. A two-stage hybrid model.

It is demonstrated, that a two-joined arm performing goal directed movements is controllable (a) by two central pattern generators (CPG) representing sampled data control, each referring to one joint, initiated for exactly one period, and producing the angular movement width about this joint, and (b) by reflex-like processes operating continuously with respect to time. The latter eliminate the effects of dynamic coupling, gravity, inertia, and mechanical impedance on the movement by 'proprioceptive feedforward' of position, velocity and acceleration signals, thus enabling the CPGs to handle the arm segments as if they were independent and free from forces. Higher ordered centers (with respect to the CPGs) therefore only need to control the kinematics, not dynamics, of the arm.

Animals↗
PubMed1989

Ensemble proprioceptive activity in the cat step cycle: towards a representative look-up chart.

Analysis of the control of movement in tasks such as stepping is severely restricted by the lack of quantitative data on the ensemble activity of afferents in the numerous muscles involved. We have started to build up a quantitative "look-up-chart" of the ensemble afferent and efferent profiles in the cat step cycle. To this end, we have developed software which allows us to digitize afferent firing, muscle length and electromyogram (EMG) activity, and to align segments for averaging by choosing one or more reference points in the step cycle. The ensemble firing of triceps surae Ia afferents showed lower than expected mean and peak rates, whereas triceps group II and Ib afferents were more active than predicted. There were small but significant transients in Ia firing at foot-off and touch-down which could not be explained in terms of origin-to-insertion length lone. They were most likely caused by propagated mechanical transients or tendon compliance effects giving rise to small differences between the origin-to-insertion length and the intramuscular length "seen" by spindles. Net ensemble Ia rates, based on previous estimates of spindle populations, probably exceed 25 kilo-impulses/second (ki.p.s.) in some muscles. Inputs as large as this are likely to contribute significantly to reflex control.

Animals↗