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PubMed1970

Cervico-lumbar reflex interactions involving a proprioceptive receiving area of the cerebral cortex.

1. In the decerebrate cat descending cervico-lumbar reflex interactions from neck muscle nerves are absent, and those from forepaw nerves are reduced or absent.2. Lesions restricted to the anterior pole of the suprasylvian gyrus regularly abolish descending cervico-lumbar reflex interactions from neck muscle nerves. The same lesions may reduce or abolish descending cervico-lumbar reflex interactions from forepaw nerves.3. The ascending cortical looping pathway utilized in descending cervico-lumbar reflex interactions is crossed, and the descending pathway from the cerebral cortex is bilateral.

Animals↗

PubMed1995

Double-blind, placebo-controlled study of botulinum toxin injections in the treatment of cervical dystonia.

Botulinum toxin injections were given to 23 patients with cervical dystonia in a double-blind, placebo-controlled, crossover study. Each patient was randomly given 100 units of botulinum A toxin and placebo in two respective sets of injections into the two most active contracting neck muscles at least 3 months apart. Before and 3 weeks after each set of injections, the cervical dystonia was "blindly" scored by the investigator. Each patient was also asked to independently score the improvement of the dystonia and neck pain. Four patients dropped out and one patient showed spontaneous remission. The remaining 18 patients completed the study and showed a significant improvement after the injections of botulinum toxin in comparison with that of the placebo. The effect started about 1 week after injection and the maximal effect lasted about 11 weeks in patients with a satisfactory response. The neck pain was satisfactorily relieved in 9 of 10 patients affected. There were no significant side effects. Thus, botulinum toxin injection is effective in treating cervical dystonias; injection of a higher dose of botulinum toxin in a greater number of neck muscles is required for those patients with complex cervical dystonia.

Adult↗

PubMed1989

Operant conditioning of head-waving in Aplysia. II. Contingent modification of electromyographic activity in identified muscles.

Aplysia can readily exhibit operant conditioning of their head-waving response when bright light is used as aversive reinforcement (Cook and Carew, 1986). In the first paper of this series (Cook and Carew, 1989a), we showed that the electromyographic (EMG) activity of a discrete band of neck muscles, the lateral columellar muscles (LCMs) of Aplysia is significantly correlated with the component of head-waving (the horizontal component) that is modified during operant conditioning. In the present paper, we asked whether the EMG activity of the LCMs themselves could also be contingently modified, using the same procedures that produce operant conditioning of the behavioral response. Differential EMG from the LCMs was recorded in freely behaving animals with chronically implanted muscle cuff electrodes. Animals receiving aversive reinforcement (bright light) that was contingent upon specific patterns of LCM activity readily learned to alter their differential EMG output. Like operant conditioning of the head-waving response, this operant modification of LCM activity was rapidly acquired and was specific to the contingencies of reinforcement. These results show that a restricted group of muscles, the LCMs, exhibit the essential features of the head-waving system observed at the behavioral level: (1) their activity is significantly correlated with head-waving behavior, and (2) the LCMs are capable of operant modification of their output. Thus, this restricted response system provides a useful preparation for examining the neural mechanisms of operant conditioning of head-waving in Aplysia.

Animals↗

PubMed1975

Electromyographic investigations in torticollis.

In 13 patients with torticollis, the electromyographic (EMG) activity in the neck muscles at rest was investigated before, during and after stimulation of the H1 bundle (in horizontal torticollis) and inner part of oral ventral nucleus (in the rotatory form), as well as after coagulation. Three EMG types of torticollis-spasmodic, myoclonic and mixed - could be differentiated. During the 8-, 25- and 50-Hz stimulations, a diminution in the amplitude and frequency of muscle potentials, followed by electric silence, was most often obtained; in general, the electric silence was preceded by a rhythmic activity of grouped potentials. Following coagulation, no spontaneous EMG activity was any longer recorded in the neck muscles, in the majority of the cases.

Diagnosis, Differential↗

PubMed1994

Presence of African horse sickness virus in equine tissues, as determined by in situ hybridization.

In a retrospective study, a negative-sense digoxigenin-labeled RNA probe, corresponding to the gene encoding nonstructural protein-1 of African horse sickness virus (AHSV) serotype 4, was applied to formalin-fixed, paraffin-embedded tissue taken from horses in the terminal stages of infection with AHSV. Fifteen infected ponies and one noninfected control were studied. Ponies exhibited a range of clinical signs and lesions. Thirteen ponies were infected with serotype 4, one with serotype 1, and one with serotype 2. Ponies were monitored clinically and euthanatized when severely clinically ill. The following tissues were available for study by in situ hybridization and histopathology: lung, heart, spleen, neck muscle, and supraorbital fat. Histologically, the most striking changes were pulmonary edema and, in some, acute myocardial necrosis. In situ hybridization revealed virus distributed widely in sections of lung and heart examined, with relatively less in spleen, neck muscle, or supraorbital fat. Virus was localized to target cells with morphologic features compatible with endothelium in all organs except spleen, where it was found in both endotheliumlike cells and large mononuclear cells.

African Horse Sickness↗

PubMed1998

Passive sustained turning of the head induces asymmetric gain of the vestibulo-ocular reflex in healthy subjects.

In order to test the hypothesis of an interaction between neck proprioception and the vestibulo-ocular reflex (VOR), we rotated 16 healthy subjects both facing forward and with their heads passively turned 70 degrees to either side. We found that gain tended to be lower when the subjects were rotated with their heads turned opposite to the direction of rotation compared to when they were rotated in the same direction, but facing forward. Although our findings were not statistically significant, they suggest that there is a measurable interaction between neck proprioception and the VOR in subjects with normal vestibular function. Asymmetric neck muscle proprioceptive signals seem to give rise to asymmetric functioning of the VOR, which, at least in part, could be the pathogenesis of cervical dizziness. If so, this could lead to misinterpretation of vestibular assessments in patients with neck pain who also complain of dizziness.

Adult↗

PubMed1986

Organization of motor pools supplying the cervical musculature in a cryptodyran turtle, Pseudemys scripta elegans. I. Dorsal and ventral motor nuclei of the cervical spinal cord and muscles supplied by a single motor nucleus.

In this and the accompanying paper (Yeow and Peterson, '86) we characterize motor nuclei of the cervical spinal cord in Pseudemys scripta and the motor pools of eight cervical muscles. We have identified three motor nuclei that supply the cervical musculature by using serial reconstructions of Nissl-stained spinal cords cut in three cardinal planes, and in experimental cases in which horseradish peroxidase (HRP) was applied to individual neck muscles. These nuclei are named according to their position as visualized in the transverse plane: dorsal, ventral, and medial. A fourth (ventrolateral) motor nucleus was never labelled following application of HRP to the cervical musculature and presumably innervates the forelimbs. The dorsal motor nucleus occupies the mid-dorsal to dorsolateral ventral horn of C1 and C2. It is composed of at least two morphological groups of motor neurons; one of these is a population of very large, fusiform profiles with transversely oriented dendrites that is found primarily in C1. The ventral motor nucleus occupies the tip of the ventral horn from C1 to C8. Its cells are significantly smaller and more numerous in rostral than in caudal cervical segments. In Nissl material, ventral nuclear profiles show little tendency to cluster into subgroups, but experimental cases suggest that there is some spatial dissociation of different motor pools within the ventral nucleus. The medial motor nucleus is described in the accompanying paper together with the motor pools of three cervical muscles that it supplies. Having identified the cervical motor nuclei we then used retrograde transport of HRP to characterize the motor pools of individual cervical muscles. Two superficial ventral muscles (mm. coracohyoideus and plastro-squamosus) are supplied by dorsal nuclear cells. M. coracohyoideus motor neurons are significantly larger than those of m. plastrosquamosus and the very large, fusiform cell type is relatively more numerous in the m. coracohyoideus motor pool. Dorsal and lateral muscles (mm. cervicocapitis, testocapitis, and transversalis cervicis) are supplied by ventral nuclear motor neurons. These cells are smaller, on average, than motor neurons supplying ventral musculature. The m. cervicocapitis motor pool lies dorsomedially in the tip of the ventral horn of C1 and C2; motor neurons supplying the more laterally placed mm. testocapitis and transversalis cervicis occur more ventrolaterally, in C2-C3 and C3-C5, respectively. Thus each of the five cervical muscles is supplied by a single motor nucleus, and their motor pools are organized into a musculotopic pattern.

Animals↗

PubMed1995

I-123 MIBG scintigraphy in adults. A report of clinical experience.

Thirty-one adult patients with clinical findings suggestive of pheochromocytoma were studied with I-123 MIBG. All patients had images obtained at 24 and 48 hours. Five patients had abnormal uptake proved to be because of I-123 MIBG avid tumors. The remaining 26 patients had no proven tumors and showed physiologic uptake in various organs. The 24-hour images were of high quality. In all cases, the 48-hour images contributed no significant additional information. Only in 1 patient did the 48-hour image add some certainty. Physiologic uptake was seen in the salivary glands, liver, G.I. tract, and urinary bladder in all patients (100%). Uptake was also observed in the lung and heart (90%), normal adrenal glands (32%), thyroid (29%), spleen (23%) uterus (13%), and neck muscles (6%). The authors' experience indicates that I-123 MIBG gives superior images compared to the previously used I-131 MIBG, that the optimum imaging time for adults is 18-24 hours, and that normal distribution patterns including uterine and neck muscle uptake should be familiar to physicians interpreting the studies.

3-Iodobenzylguanidine↗

PubMedDate not supplied

Influence of FLA-63 on pentobarbitone sleep in chicks and rats.

The influence of FLA-63 on pentobarbitone-induced sleep was studied in young chicks and adult rats. FLA-63 produced a time-dependent biphasic effect on the gross behaviour of chicks and rats; an initial sedation followed by behavioural excitation. The behavioural effects of FLA-63 were associated with an initial EEG synchronization prior to an increased activity of the EMG of the neck muscle and desynchronization of the EEG of the hyperstriatum, optic tectum and pontine reticular formation of the chick. Similarly, in rats, the EEG of the frontal cortex, optic lobe and pontine reticular formation was desynchronized while the EMG activity of the neck muscle was enhanced by FLA-63. FLA-63 delayed the onset and shortened the duration of pentobarbitone sleep. Pentobarbitone-induced EEG synchronization and decreased EMG activity in chicks was antagonized by FLA-63. Dopamine-induced antagonism of pentobarbitone sleep was potentiated by FLA-63 in chicks. Levodopa antagonized pentobarbitone-induced sleep in rats and this effect was potentiated by FLA-63. FLA-63 potentiated levodopa-induced desynchronization of the EEG of the frontal cortex, optic lobe and pontine reticular formation of the rat. Haloperidol antagonized the effect of FLA-63 on pentobarbitone-induced sleep in both rats and chicks. Noradrenaline induced behavioural sleep in young chicks dose-dependently; this effect was antagonized by phentolamine. In the rat, phentolamine shortened pentobarbitone sleeping time but did not significantly influence the effects of FLA-63 on pentobarbitone sleep. Those results suggest that an increased dopamine neurotransmission may be associated with the mechanism of wakefulness in chicks and rats.

Animals↗

PubMed2001

Performance and muscle activity during computer mouse tasks in young and elderly adults.

The influence of age on performance and muscle activity was studied during computer mouse tasks designed to induce high demands on motor control. Eight young (mean age 25 years) and nine elderly (mean age 63 years) women participated. When the speed was self-determined, the elderly subjects performed 13%-18% slower than did the young. When speed was predefined, the error rate was higher in the elderly subjects than in the young ones (medium precision 7.8% compared to 2.5%, high precision 16.5% compared to 7.9%, respectively). The highest error rate was found for double-clicking (32.9% compared to 13.5%, respectively). The reduced performance in the elderly subjects was hypothesised to be a combined effect of deteriorated proprioception, increased motor unit size, and changes in the central nervous system. Electrical activity (EMG) was recorded from the forearm, shoulder and neck muscles. Higher levels of EMG activity were found in the elderly compared to the young. A likely explanation is that the impaired motor control necessitated an increased muscle activity. The highest levels of EMG activity and lack of EMG gaps were found for the forearm extensor muscles, especially the extensor digitorum muscle (mean EMG activity 10.4% compared to 8.1% of maximal electrical activity, EMGmax) whereas lower EMG activity levels were found for the shoulder region (e.g. right trapezius muscle mean EMG 2.8% compared to 1.1% EMGmax, respectively). The latter was possibly due to a relieving effect of the forearm support. Differences in muscle activity among the tasks were found, however they were minor for the shoulder and neck muscles. Consideration of the demands on motor control when designing user interfaces is recommended, to the benefit of both the young and the elderly.

Adult↗

PubMed1987

Stability of the head: studies in normal subjects and in patients with labyrinthine disease, head tremor, and dystonia.

The dynamics of postural control of the head were investigated in normal human subjects and patients with neurological disease. The technique adopted was to measure the head movements provoked by passive, unpredictable oscillations of the trunk in the frequency range 0-6-7 Hz when subjects were required (a) to try to stabilise their head "in space" and (b) to try to make their heads move "en bloc" with the trunk. Head movement responses were characterised by the gain and phase with respect to trunk movement (transfer function) and degree of linear relationship between head and trunk (coherence). The normal transfer function approximated a cascade of two second-order, underdamped, systems representing the passive inertial, viscous, and elastic properties of the muscle and joints of the head and neck. Stabilisation of the head "in space" produced about 40% reduction in transmission of body movement, was only evident at frequencies less than 1 Hz and was affected partly by voluntary movements. An alabyrinthine patient could also achieve some spatial stabilisation. The findings indicate a weak role for vestibular-collic reflexes and emphasise that the primary control of head posture during unpredictable movement is through the tonic visco-elastic properties of neck muscles that work to stabilise the head on the shoulders. In patients with dystonia of the neck and essential and cerebellar head tremor, the head showed a tendency to unstable oscillation (resonance). The instability and dystonia could be measured in terms of visco-elastic constants and damping ratios. The head movements of some tremor patients did not linearly follow the trunk movement, showing that the motion stimulus provoked abnormal phasic muscle activity at frequencies other than those of the tremor. The technique quantifies head control in movement disorders and is sensitive to abnormal function.

Adolescent↗

PubMed2000

Vestibular schwannoma surgery and headache.

The aim of the study was to evaluate aetiological factors for postoperative headache after vestibular schwannoma (VS) surgery with respect to asymmetric activation of vestibular reflexes. After surgery, 27 VS patients with persistent postoperative headache, 16 VS patients without headache and 9 healthy controls were examined. The vestibular, cervicocollic and cervicospinal reflexes were evaluated to study whether asymmetric activation of vestibular reflexes could cause headache. The effect of neck muscle and occipital nerve anaesthesia and the effect of sumatriptan on headache were also evaluated. The vestibular function of VS patients with headache did not differ from that of VS patients without headache, but was abnormal when compared to that of normal controls. The cervicospinal and cervicocollic reflexes did not differ in the patient groups. Injection of lidocaine around the operation scar gave pain relief to two patients, and one of them had occipital nerve entrapment. Infiltration of lidocaine deep in the neck muscles in the vicinity of the C2 root did not alleviate headache, but caused vertigo. Nine patients with musculogenic headache got pain relief from supportive neck collars, and two patients with cervicobrachial syndrome got pain relief from manual neck traction. The study shows that asymmetric activation of cervicocollic reflexes does not seem to be the reason for headache. Headache seems to be linked to neuropathic pain, allegedly caused by trigeminal irritation of the inner ear and the posterior fossa, which has recently been linked to vascular pain.

Adult↗

PubMed2001

Spontaneous craniocervical osseous fusion resulting from cervical dystonia. Case report.

The authors report on a 31-year-old man with spontaneous craniocervical osseous fusion secondary to cervical dystonia (CD). After an 8-year history of severe CD, the patient developed a fixed rotation of his head to the right. Three-dimensional computerized tomography reconstructions revealed rotation and fixation of the occiput and C-1 relative to C-2, which was similar to that seen in atlantoaxial rotatory fixation. There was abnormal ossification of the odontoid facet joints and ligaments. Additional ossification was observed in the cervical soft tissue bridging the lateral mass of C-1 and the occiput. The patient underwent partial myectomy of the dystonic left sternocleidomastoid muscle and selective posterior ramisectomy of the right posterior neck muscles; postoperatively he experienced relief of his neck pain. In patients with CD refractory to conservative treatment, the appropriate timing of surgical treatment is important.

Adult↗

PubMed2006

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↗

PubMed1995

Physiological study of cervical dystonia. Task-specific abnormality in contingent negative variation.

To investigate the pathophysiology of dystonia, we recorded contingent negative variation (CNV) in 12 patients with cervical dystonia and in 12 age-matched normal subjects. In a simple reaction time paradigm, the subjects were given a pair of a warning stimulus and a subsequent stimulus that triggered head rotation to either side or extension of the fingers. In normal subjects, CNVs for head rotation were not affected by neck muscle pre-activation simulating torticollis, and were always symmetrical with equally high amplitudes over the frontal and central leads. By contrast, CNVs for finger movement had the maximum over the central lead and showed a characteristic distribution; those for the right finger movement had the left hemisphere dominance, whereas those for the left finger movement had similar amplitudes over both hemispheres. In patients with rotatory torticollis (rotatocollis), the components of CNVs for head rotation were markedly attenuated in all the leads, except for the initial negative deflection (orienting response). As a whole, cervical dystonia patients had significantly lower amplitudes of late CNVs for head rotation than normal subjects (P < 0.001), whereas late CNV amplitudes in finger extension did not differ in the two groups. Their reaction times for head rotation were similar, but durations of EMG activities were prolonged in the patients because of co-contractions of the antagonists. The task-specific CNV amplitude loss is therefore not explained by reaction times or by the abnormal neck muscle activities prior to the movement, but it reflects a failure of neural activities preparing for a phasic neck movement, resulting in co-contraction of the agonists and the antagonist. Dystonia may be associated with defective retrieval or retaining of specific motor programmes or subroutines in response to sensory stimuli.

Adult↗

PubMed1988

Neuromuscular effects distant from the site of botulinum neurotoxin injection.

We assessed the severity and temporal profile of distant neuromuscular effects from a single dose (280 units) of botulinum neurotoxin injected into neck muscles for torticollis. We performed single-fiber EMG studies on the biceps brachii of six patients to measure jitter (20 pairs) and fiber density on the initial treatment day and then again, at least once more, after 2 to 12 weeks. No patient developed weakness beyond the neck muscles or decrement of the biceps response to repetitive 3-Hz nerve stimulation. Between the baseline and the last follow-up study, the average of mean MCD increased from 29 microseconds to 38 microseconds (31%). Mean fiber density increased concurrently or earlier from 1.35 to 1.79 (33%). There were no electrophysiologic signs of presynaptic blockade, even at 2 and 4 weeks. The effects we observed are compatible with stimulation of terminal sprouting by the neurotoxin, without significant presynaptic inhibition of acetylcholine release. We therefore believe that higher dosages of the neurotoxin may be used if clinically indicated.

Adult↗

PubMed1988

Neurotoxic lesions of the dorsolateral pontomesencephalic tegmentum-cholinergic cell area in the cat. II. Effects upon sleep-waking states.

Kainic acid was injected bilaterally (4.8 micrograms in 1.2 microliters each side) into the dorsolateral pontomesencephalic tegmentum of cats in order to destroy the cholinergic neurons located in that region and thus to study the effects of their destruction upon sleep-waking states. The kainic acid produced a large area of nerve cell loss and/or gliosis centered in the dorsolateral tegmentum-cholinergic cell area, that includes the pedunculopontine tegmental (PPT) and laterodorsal tegmental (LDT) nuclei rostrally (A1-P2), and the parabrachial (PB) and locus coeruleus (LC) nuclei caudally (P3-P5). The mean loss of choline acetyltransferase (ChAT)-immunoreactive neurons within this area was 60% with a range from 25% to 85% across 11 cats. The mean loss of tyrosine hydroxylase (TH)-immunoreactive neurons, differentially distributed through the same region, was 35% with a range of 0-50%. Whereas the kainic acid lesions appeared to have only slight effects upon wakefulness and slow-wave sleep, they had marked effects upon paradoxical sleep (PS), which varied in degree across animals. In cats with the most extensive destruction of cholinergic neurons, PS was eliminated in the first few weeks following the lesion and then reappeared as isolated episodes characterized by sparse, low amplitude PGO spikes in association with few eye movements and an activated cortex, though in absence of neck muscle atonia. Although these PS-like episodes varied in amount, they were significantly less than baseline PS in percent and in duration for the group of 11 animals over one month recording. The PGO spike rate was significantly reduced; the EMG amplitude was significantly increased, marking a loss of neck muscle atonia. The percent of PS-like epochs, the rate of PGO spiking and the EMG amplitude on postlesion day 28 were found to be significantly correlated with the volume of the lesion within the dorsolateral pontine tegmentum-cholinergic cell area. The percent PS-like episodes and PGO spike rate were significantly correlated with the number of remaining ChAT-immunoreactive neurons, but not with the number of remaining TH-immunoreactive neurons within this region. These results suggest that cholinergic pontomesencephalic neurons may be critically involved in the generation of paradoxical sleep and its phasic events.

Acetylcholine↗

PubMed2006

Prism adaptation first among equals in alleviating left neglect: a review.

PURPOSE: The current paper was designed to provide a critical overview on the different methods proposed for the rehabilitation of left spatial neglect. METHODS: On the basis of a previous systematic review of the literature, we analyzed all articles available aiming at reducing left spatial neglect which included a long term functional assessment. RESULTS: The aim of most early rehabilitation approaches, such as visuo-scanning training, was to re-orient visual scanning toward the neglected side. This review confirmed the utility of this method for rehabilitation purposes. More recent - theory driven - procedures, also based on a training approach, include limb activation, mental imagery training and video-feedback training. Although there is ground for optimism, the functional effectiveness of these methods still relies on few single-case studies. Newer methods have tried to stimulate automatic orientation of gaze or attention towards neglected space in a bottom-up fashion. Sensory stimulations can remove most of the classical signs of left neglect but their effects are short-lived. Such stimulations are not functionally relevant for rehabilitation except for trunk rotation or repeated neck muscle vibrations if they are associated with an extensive training program. A more promising intervention is prism adaptation given the growing evidence of relatively long-term functional gains from comparatively short term usage. CONCLUSION: Overall, there is now evidence for several clinically relevant long-term benefits in the case of visual scanning training, mental imagery training, video feedback training, neck muscle vibration and trunk rotation if associated with visual scanning training and prism adaptation. However, the amount of evidence is still limited to a small number of relevant published articles and it is mandatory to continue the research in this field. In this review, the possible routes for new rehabilitation procedures are discussed on the basis of the actual knowledge regarding the neuro-cognitive mechanisms underlying the therapeutic effect of prism adaptation.

Adaptation, Physiological↗