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PubMed1989

Delayed muscle fiber transformation after foreign-reinnervation of excessive muscle tissue.

Following partial denervation motor units can increase (by self-reinnervation) as much as four to five times their normal size. To investigate the still unknown quantitative reinnervation capacity of a motor nerve in the case of foreign-reinnervation, in adult male rats the denervated sternomastoid muscle was either self-reinnervated by its original nerve or foreign-reinnervation by the omohyoid nerve, which had to reinnervate the three times the amount of muscle fibers and six times the amount of muscle mass. After survival times of 7, 8, 9, or 10 months, nerves and muscles were investigated histochemically and immunohistochemically. The omohyoid nerve could fully reinnervate the sternomastoid muscle, but at 7 and 8 months this muscle still revealed nearly the same proportions of IIA and IIB fibers as were seen in the self-reinnervated sternomastoid at all stages. However, in the following 2 months a shift of the fiber pattern toward that of the normal omohyoid was observed, as evidenced by a strong increase in type IIB fibers (from 24% to 62%), at the expense of type IIA fibers. These findings are in contrast to those after foreign (cross) reinnervation of leg muscles where the fiber transformation (according to the foreign motor input) occurs in parallel with the reinnervation process during the first 2-3 months. The delayed fiber transformation observed could be the consequence of the highly enlarged peripheral field of the omohyoid motoneuron pool or could merely reflect a general difference between limb and neck muscles.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2005

Abnormal head nociceptive withdrawal reaction to facial nociceptive stimuli in Parkinson's disease.

INTRODUCTION: Trigemino-cervical-spinal reflexes (TCSRs) are complex brainstem stereotyped nociceptive responses involved in a defensive withdrawal reaction of the head from facial nociceptive stimuli. OBJECTIVE: The present study was undertaken to collect data on possible TCSR abnormalities in idiopathic Parkinson's disease (PD) and investigate any correlation with motor signs and L-DOPA administration. METHODS: TCSRs were registered from the semispinalis capitis and biceps brachii muscles after electrical stimulation of the supraorbital nerve in 18 patients with PD and 24 controls. The latency (L) and area (A), as well as the sensory (ST), painful (PT) and reflex (RT) thresholds were measured during the 'off' and 'on' state, and possible correlations with the UPDRS III total score, selected subscores (tremor, neck rigidity, upper limb rigidity, akinesia, rising from a chair, posture and posture instability) and duration of illness were investigated. RESULTS: Significant changes between controls and PD patients were found in the L, A, PT and RT of TCSRs. These results were not significantly influenced by L-DOPA treatment. A significant correlation was found between neck rigidity, postural instability scores and duration of illness and the TCSR L and A values in PD patients in the 'off' state. CONCLUSIONS: TCSRs abnormalities, combined with dopamine resistance, are consistent with a primary loss of brainstem neurons mediating a complex sensory-motor integration including neck muscle tone and postural control as well as the head withdrawal reaction to the nociceptive stimuli. SIGNIFICANCE: TCSRs may represent a useful tool for the assessment of brainstem sensory-motor function in PD as well as other movement and degenerative disorders.

Aged↗
PubMed2006

Can the results 6 months after anterior cervical decompression and fusion identify patients who will have remaining deficit at long-term?

PURPOSE: There is no knowledge if short-term outcome in patients after anterior cervical decompression and fusion (ACDF) can be used to identify which patients have remaining deficit in long term. This study investigates if 6-month outcome with a broad assessment after ACDF with a cervical intervertebral fusion cage can be a guide for the 3-years outcome. METHOD: A prospective study. Questions about background data, pain, numbness, neck specific disability, distress, sick leave, health, symptom satisfaction and effect of and satisfaction with surgery were asked 28 patients 3 years after ACDF. Measurements have earlier been obtained before and 6 and 12 months after ACDF. RESULTS: Compared with the results before surgery patients had improved in pain intensity (p = 0.001), neck pain (0.001), numbness (p = 0.02) and were more 'satisfied' with having their neck problems (p = 0.01). Except for a worsening in expectations of surgery fulfilled (p = 0.04) there were no significant differences between 6-month and 3-year outcome. Three years after ACDF about two-thirds of the patients had remaining deficit with regard to pain intensity, Neck Disability Index, Distress and Risk Assessment Method and general health. According to the parameters studied 50 - 78% of those who at the 6-month follow-up were without deficit were still healthy at the 3-year follow-up. For patients with deficit at 6-month follow-up, still 83 - 100% had deficit 3 years after surgery. CONCLUSIONS: Despite a rather small study obtained the stability of 6-month and 3-year results indicates that short-term results might be sufficient for evaluating effects of the treatment. Since the patients in this study clearly demonstrate broad problems array of development of more structured multi-professional rehabilitation models including exercises which improve neck muscle strength, endurance and proprioception need to be introduced.

Adult↗
PubMed1984

The central control of fetal breathing and skeletal muscle movements.

Breathing movements in the sheep fetus have been observed from a gestational age of about 40 days. From 95 to 115 days fetal breathing movements are almost continuous, interrupted by apnoea rarely exceeding 2 min. From 115 days until term (about 147 days) breathing and movements of the trunk and limbs are episodic. Breathing normally occurs only during rapid-eye-movement sleep as identified by low-voltage cortical electrical activity. Active movements of the neck muscles occur predominantly in high-voltage electrocortical activity. Hypercapnia or acid cerebrospinal fluid perfusion cause an increase in the regularity and depth of breathing when present, and recruit intercostal and laryngeal abductor activity. Isocapnic hypoxia, however, in contrast to the hyperventilation seen postnatally, causes arrest of fetal breathing movements. This effect is due to a central inhibition. Section of the brain stem, from the caudal hypothalamus rostrally, causes dissociation of fetal breathing movements and electrocortical activity into independent rhythms. Section of the brain stem caudally, in the upper pons or at the inferior colliculus, also causes a dissociation of electrocortical activity from breathing movements, which become almost continuous. Isocapnic hypoxia causes an increase in the rate and depth of breathing movements. It is concluded that the arrest of breathing in intact fetal lambs is not due to a direct effect on the respiratory centre in the medulla. The lumbar polysynaptic flexor reflex response becomes episodic after 115 days gestation but, in contrast to fetal breathing movements, is enhanced during high-voltage electrocortical activity. Isocapnic hypoxia arrests movements of the fetal limbs and trunk and inhibits the lumbar flexor reflex. This inhibition of the reflex is prevented by section of the spinal cord at T12, but persists after section of the brain stem in the upper pons. It is attributed to an action on the medulla, independent of the systemic arterial chemoreceptors. Small doses of pentobarbitone (5 mg/kg) cause arrest of fetal breathing movements by a suprapontine mechanism, abolished by brain stem transection, and inhibition of the lumbar flexor reflex by an action on the spinal cord, persisting after transection at T12. Inhibitors of prostaglandin synthetase (indomethacin, meclofenamate or aspirin) induce continuous fetal breathing movements, while prostaglandin E2 arrests fetal breathing. The site of action is on the medulla, as shown by section of the brain stem and of afferents from the systemic arterial chemoreceptors.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1994

[A sporadic case of essential vitamin E deficiency manifested by sensory-dominant polyneuropathy and retinitis pigmentosa].

A 55-year-old woman with known retinitis pigmentosa for 25 years was progressively clumsy in gait and activities of daily living over the past 30 years. She was able to manage house work and social activities, but she developed swallowing disturbance associated with involuntary neck muscle spasm for 2 weeks, which brought her to our clinic on September 7, 1990. General physical examination was normal except for dry skin. Neurological examination was compatible with sensory-dominant polyneuropathy, showing distal dominant sensory impairment together with absent vibration sense and areflexia in lower limbs, but no gross muscular weakness. There were neck dystonia and bilateral poor visual acuity due to secondary optic atrophy of retinitis pigmentosa. The former responded to the combination of tiapride and trihexyphenidyl. She was admitted twice for further evaluation. Complete blood count and blood chemistry tests including lipids were all within normal limits, and so was cerebrospinal fluid. Pyruvate and lactate before and after exercise loading were also normal. Malignancy workup was negative. To our surprise, serum vitamin E level turned out very low (1.89 micrograms/ml), normal range being 4.7-20.3 micrograms/ml. Oral vitamin E administration test by 2g of alpha-tocopherol showed abnormal absorption curve followed fast clearance in serum. Stool was occasionally positive for fat corpuscles by Sudan III staining, but 99Tc-HSA leakage into the intestines was not detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy↗
PubMed1980

Sleep, wakefulness and the monosynaptic reflex in fetal and newborn lambs.

1. Electrocorticogram (ECoG), electromyogram (EMG) of the lateral rectus and antigravity muscles (neck and masseter) and breathing activity (FB) were monitored in chronically prepared fetal sheep of 125-140 days gestation and in newborn lambs up to 11 days postnatal age. 2. Awake state (AW), non-rapid eye movement sleep (NREM) and rapid eye movement sleep (REM) were defined using standard criteria for ECoG, eye movements and postural muscle tone. 3. The percentage of time the fetuses spent in each state was: NREM sleep 53%, REM sleep 41.4%, and AW 5.6%. 4. Spontaneous intrauterine breathing activity occurred only during REM sleep, but 35% of REM sleep was not associated with FB. 5. Gasps (isolated deep inspirations) appeared occasionally throughout the recording and were not related to any specific sleep state or wakefulness. 6. In the fetus, the monosynaptic reflex (MSR) induced by direct electrical stimulation of the fibular nerve was enhanced by about 75% during REM sleep compared to NREM and AW. In the newborn lamb the adult pattern of suppression of MSR during REM sleep was not seen until several days after birth.

Animals↗
PubMed1996

Distinct regulatory elements control muscle-specific, fiber-type-selective, and axially graded expression of a myosin light-chain gene in transgenic mice.

The fast alkali myosin light chain 1f/3f (MLC1f/3f) gene is developmentally regulated, muscle specific, and preferentially expressed in fast-twitch fibers. A transgene containing an MLC1f promoter plus a downstream enhancer replicates this pattern of expression in transgenic mice. Unexpectedly, this transgene is also expressed in a striking (approximately 100-fold) rostrocaudal gradient in axial muscles (reviewed by J. R. Sanes, M. J. Donoghue, M. C. Wallace, and J. P. Merlie, Cold Spring Harbor Symp. Quant. Biol. 57:451-460, 1992). Here, we analyzed the expression of mutated transgenes to map sites necessary for muscle-specific, fiber-type-selective, and axially graded expression. We show that two E boxes (myogenic factor binding sites), a homeodomain (hox) protein binding site, and an MEF2 site, which are clustered in an approximately 170-bp core enhancer, are all necessary for maximal transgene activity in muscle but not for fiber-type- or position-dependent expression. A distinct region within the core enhancer promotes selective expression of the transgene in fast-twitch muscles. Sequences that flank the core enhancer are also necessary for high-level activity in transgenic mice but have little influence on activity in transfected cells, suggesting the presence of regions resembling matrix attachment sites. Truncations of the MLC1f promoter affected position-dependent expression of the transgene, revealing distinct regions that repress transgene activity in neck muscles and promote differential expression among intercostal muscles. Thus, the whole-body gradient of expression displayed by the complete transgene may reflect the integrated activities of discrete elements that regulate expression in subsets of muscles. Finally, we show that transgene activity is not significantly affected by deletion or overexpression of the myoD gene, suggesting that intermuscular differences in myogenic factor levels do not affect patterns of transgene expression. Together, our results provide evidence for at least nine distinct sites that exert major effects on the levels and patterns of MLC1f expression in adult muscles.

Animals↗
PubMed1999

Support stability influences postural responses to muscle vibration in humans.

We studied the effect of support stability on postural responses to the vibration of Achilles tendons and of neck dorsal muscles in healthy humans. For this purpose we compared postural responses on a rigid floor and on 6 cm high rocking supports (see-saws) of different curvatures (different radii: 30, 60 and 120 cm). The subject stood with eyes closed, the centre of the feet coincided with the centre of the see-saw. We recorded platform tilt, horizontal displacements of the upper body, ankle joint angle and activity of ankle joint muscles. On the rocking platform subjects maintained balance in a sagittal direction by making see-saw rotations placing the support under the body's centre of gravity. Equilibrium maintenance requires that the torque in the ankle joint increases during forward body displacements, as on the rigid floor, and be accompanied by a plantar flexion (not by a dorsiflexion) in the ankle joint. The directional dependence of vibration-induced reactions on the see-saw was the same (relative to space) as on the rigid floor: backward body displacement during Achilles tendon vibration and forward body displacement during neck muscle vibration. A decrease of support stability (with a decrease of the radius from 120 to 30 cm) diminished significantly the effect of Achilles tendon vibration and to a lesser extent the effect of neck muscle vibration. In contrast, the increase of platform stability by hand contact with a stable external object gave rise to prominent body sway in response to Achilles tendon vibration. Neck muscle vibration on the movable support provoked a quick initial forward body sway. This initial quick response was absent during vibration of the Achilles tendons. We conclude that postural responses to muscle vibration reflect the participation of different muscles in posture control and depend on the support properties. Support instability changes the role of proprioceptive information and the state of the system of equilibrium maintenance.

Achilles Tendon↗
PubMed1996

Ocular exploration of space as a function of neck proprioceptive and vestibular input--observations in normal subjects and patients with spatial neglect after parietal lesions.

We recently argued that the specific compensation of spatial neglect by manipulating neck proprioceptive and vestibular input is due to a central "correction" of the disturbed neural transformation process converting the afferent input coordinates from the peripheral sensory organs into a central representation of egocentric space. Both types of stimulation were proposed to induce a reorientation of the deviated or distorted egocentric spatial reference frame. The aim of the present study was to observe this process of reorientation under a condition in which no visual stimulus can attract the subject's attention and thus influence exploration behaviour from outside. We recorded eye movements of normal subjects and of three patients with spatial neglect after right parietal lesions while searching for a non-existent target in complete darkness. It was assumed that the area of the outer space that subjects spontaneously explore under this condition is a direct function of the subject's representation of egocentric space. Ocular space exploration was biased and confined almost entirely to the right side of the midsagittal plane in patients with neglect. This spatial distribution of exploratory eye movements changed remarkably with left-sided neck muscle vibration as well as with left-sided vestibular stimulation using ice water calorics. The spatial area of exploration was significantly enlarged to the contralesional side and the exploration maximum shifted in the same direction. Whereas with both types of stimulation space exploration of patients with neglect was similar to that of normal subjects when not being stimulated, neck proprioceptive and vestibular stimulation in normal subjects induced a quasi neglect-like exploration pattern, i.e. a bias to one side of the objective midsagittal plane. If ocular space exploration was, however, related to the subjectively perceived position of the midsagittal plane in space, eye movements were symmetrically distributed and carried out to both sides of subjective "straight ahead" in all experimental conditions, in normal subjects as well as in patients with neglect. The present results support the above hypothesis and indicate that neck proprioceptive as well as vestibular input directly contribute to the computation of the subject's central representation of egocentric space used for localizing body orientation and for guiding motor behaviour in space.

Adult↗
PubMed2001

A clinical spectrum of the myoclonic manifestations associated with typical absences in childhood absence epilepsy. A video-polygraphic study.

We investigated the electroclinical features of 12 patients with childhood absence epilepsy (CAE), presenting with typical absence seizures associated with myoclonic manifestations of the face or neck. All patients underwent repeated and prolonged split-screen video-polygraphic EEG recordings. The polygraphic recordings and clinical correlations of the absence seizures were analysed. All patients presented with multi-quotidian, typical absence seizures. During the absences, the patients could show mild, rhythmic, myoclonic jerks involving facial areas (eyebrows, nostrils, perioral region, chin) or neck muscles (sternocleidomastoideus), with the same frequency as the spike-wave complexes. Polygraphic tracings demonstrated that the myoclonias were correlated to the spike component. Clinically, all patients showed a benign course, with complete seizure control under antiepileptic treatment. In the follow-up, 7 patients withdrew from treatment without relapse. We conclude that all our patients showed an electroclinical picture consistent with CAE. The occurrence of myoclonic manifestations of the face or neck associated with the absences did not influence the benign course of their disease. The electroclinical features observed in our group of patients differentiates our cases both from epilepsy with myoclonic absences and from absences with perioral myoclonia (with Video).

Child↗
PubMed2005

Effect of aging on performance, muscle activation and perceived stress during mentally demanding computer tasks.

OBJECTIVES: This study examined the effects of age on performance, muscle activation, and perceived stress during computer tasks with different levels of mental demand. METHODS: Fifteen young and thirteen elderly women performed two computer tasks [color word test and reference task] with different levels of mental demand but similar physical demands. The performance (clicking frequency, percentage of correct answers, and response time for correct answers) and electromyography from the forearm, shoulder, and neck muscles were recorded. Visual analogue scales were used to measure the participants' perception of the stress and difficulty related to the tasks. RESULTS: Performance decreased significantly in both groups during the color word test in comparison with performance on the reference task. However, the performance reduction was more pronounced in the elderly group than in the young group. Likewise, a higher level of self-reported stress was found for the elderly participants after the color word test. During the reference task higher electromyographic levels and reported difficulty were recorded for the elderly group than for the young group. CONCLUSIONS: The findings suggest that mental demands affect young and elderly women differently. Thus the mentally demanding computer task had a more pronounced effect on the elderly than on the young. In contrast to the results in the reference task, the same level of muscle activity for most muscles and the same level of self-reported difficulty was found in the two groups during the color word test. The elderly probably compensated for age-related changes by reducing their work speed markedly.

Adaptation, Physiological↗
PubMed1993

[Abnormalities in behavior in the oral and cervical area: reassurance breast-feeding. Considerations on sudden infant death].

The oral zone reflects the relational modalities of the child: the sensorimotor physiological and psychological behaviour is established according to the development of the facial sphere and its aero-digestive crossroads. In the baby, the mandibular equilibrium and position and the dimensions of the lower part of the face essentially depend upon praxic activities, which drive the mandibular and hyoid displacements. During the period of immaturity, the lingual area is brought into movement with each "sucking-swallowing" action that characterises breast-feeding: the mandibulo-hyoid swing is subordinate to the pharyngo-lingual complex. The analysis of this psycho-motor behaviour reveals imperfect and upsetting "mimics" that modify the balance of the jaw and of the hyo-lingual area during swallowing, which is the second phase of the reassurance breast-feed. The lingual ptosis causes congestion of the airways. These lax children, with a receding chin, are deformed by their oral habits. The clinical picture evidences the constitutional hyperlaxity by examining the parental group -the same facial dystrophies, the same habits resulting in various disorders of general or cervical statics. At the level of the temporomandibular joint, the dysfunction is also accompanied by claudication by mandibulo-hyo-lingual tipping. The general and cervical statics of the baby are thus affected in the course of sleep. It is during paradoxical sleep that the baby's head tips on to the thorax, due to the resultant atonia of the neck muscles. The head, insufficiently supported on its cervical pillar accentuates the asphyxial mechanism provoked by the tipping of the lingual area on the epiglottis.(ABSTRACT TRUNCATED AT 250 WORDS)

Deglutition Disorders↗
PubMed1992

Connections between utricular nerve and dorsal neck motoneurons of the decerebrate cat.

1. We studied connections between the utricular (UT) nerve and dorsal neck motoneurons in decerebrate cats. Electrodes were fixed in place on the UT nerve under visual observation; the other branches of the vestibular nerve were transected. 2. The N1 field potential evoked by UT nerve stimulation was recorded in the vestibular nuclei at the start of each experiment. The potential typically grew until it reached a plateau. Stimulus spread (if any) to the central ends of other nerve branches was revealed by an additional increase in N1 amplitude after the plateau was reached. 3. We recorded intracellularly from 55 motoneurons in C1-C3. Some were identified as having axons in the dorsal rami, which innervate dorsal neck muscles. Others projected in nerves that were not available for stimulation. 4. UT nerve stimulation evoked synaptic potentials in essentially all motoneurons studied. The predominant pattern consisted of disynaptic excitatory postsynaptic potentials in ipsilateral motoneurons and inhibitory postsynaptic potentials that were at least trisynaptic in contralateral motoneurons. 5. The results demonstrate the presence of short-latency connections between the utricular nerve and dorsal neck motoneurons. The functional role of this pathway remains to be investigated.

Animals↗
PubMed1996

Morphology of single axons of tectospinal neurons in the upper cervical spinal cord.

Morphology of single axons of tectospinal (TS) neurons was investigated by intraaxonal injection of horseradish peroxidase (HRP) at the upper cervical spinal cord of the cat. TS axons were electrophysiologically identified by their direct responses to stimulation of the contralateral superior colliculus (SC). None of these axons responded to thoracic stimulation at Th2. Three-dimensional reconstructions of the axonal trajectories were made from 20 well-stained TS axons at C1-C3. Cell bodies of these axons were located in the intermediate or deep layers of the caudal two-thirds of the SC. Usually, TS axons had multiple axon collaterals, and up to seven collaterals were given off per stem axon [2.7 +/- 1.6 (mean +/- S.D.); n = 20]. Collaterals had simple structures and ramified a few times mainly in the transverse plane. The number of terminals for each collateral was small. These collaterals terminated in the lateral parts of laminae V-IX, mainly in laminae VI, VII, and VIII. There were usually gaps free from terminal arborizations between adjacent collaterals, because the rostrocaudal spread of each collateral (mean = 700 microns) was narrower than the intercollateral interval (mean = 2,500 microns). Seven of the 19 TS axons had terminals in the lateral parts of laminae V-VIII, with little projection to lamina IX, and the other 12 axons had terminals in lamina IX besides the projection to the lateral parts of laminae V-VIII. Axon terminals in lamina IX did not appear to make contacts with the somata or proximal dendrites of retrogradely labeled motoneurons, but contacts were found with the somata of counterstained interneurons in the lateral parts of laminae V-VIII. Three spinal interneurons (two in lamina VIII and one in lamina V at C1) that received monosynaptic excitation from the SC were stained, and their axonal trajectories were reconstructed. They had multiple axon collaterals at C1-C2 and mainly projected to laminae VIII and IX, with smaller projections to lamina VII. Many axon terminals of the interneurons were found in multiple neck motor nuclei, where some of them made contacts with retrogradely labeled motoneurons. The present finding provides evidence that the direct TS projection to the spinal cord may influence activities of multiple neck muscles, mainly via spinal interneurons, and may play an important role in control of head movement in parallel with the tectoreticulospinal system.

Animals↗
PubMed2001

[A case of elderly onset Parkinson's disease complicated by dropped head syndrome].

An 86-year old man presented with a 7-year history of gait disturbance. He was admitted to our hospital on April 2000 because he was experiencing difficulty eating due to progression of dropped head syndrome. Upon standing and sitting, remarkable dropped head and kyphosis were observed. When lying, the patient was able to stretch his neck, and he could stand and walk with the aid of a walker. Rigidity and resting tremor were present predominantly in the lower limbs. Parkinson's disease was diagnosed therefore L-dopa and Cabergoline were administered. Parkinsonism and dropped head syndrome improved in response to treatment. Cases involving dropped head syndrome due to Parkinson's disease are reportedly improved by L-dopa, but exasperated by dopamine agonists. The mechanism of dropped head is thought to be an imbalance in the tonus of the anterior and posterior neck muscles. Dropped head in the present case may have been a complication of Parkinson's disease since it improved in response to L-dopa.

Aged↗