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At least 343 records · Page 19Linked to original sources
PubMed2003

Time-series analyses of mandibular and perioral soft tissue movements during mastication.

Masticatory movements are rhythmically repeated and coordinated movements of the jaw, tongue and facial muscles. Thus, we considered that the elucidation of movements that are specific to perioral soft tissue, as a result of perioral facial muscle activities, should be useful for evaluation of the smoothness of masticatory movements. The aim of this study was to evaluate the smoothness of masticatory movements from the component of movements that are specific to perioral soft tissue during mastication by the application of time-series analysis. The subjects were 15 healthy persons with complete natural dentition. The experimental food used for mastication in this study was sufficiently softened chewing gum. The results showed that the component of movements that are specific to perioral soft tissue during mastication are the equal repetition spatially and stable movements temporally, and that these movements have the same accurate rhythm as that of mandibular movements and cooperate with mandibular movements temporally. Moreover, the results suggested, from the viewpoint of kinematics, that the innervation of the central pattern generator was concerned with the neural basis of rhythm generation of perioral facial muscles. Therefore, the component of movements that are specific to perioral soft tissue during mastication is useful for evaluation of the smoothness of masticatory movements.

Adult↗
PubMed2001

Neural network and wavelet recognition of facial electromyographic signals.

The present aim was to explore the possibilities of using neural networks for recognizing significant changes in electrical activity of human facial muscles. We used multilayer perceptron neural networks to recognize bursts of electromyographic signals recorded with bipolar surface electrodes from two subject's facial muscles. Wavelets were applied for the detection of high frequency components of electromyographic signals. Coefficients of wavelets were used as an input to a neural network in order to differentiate bursts from the signals. The results showed that the recognition of bursts was very successful resulting to 84-97 percent total accuracies. The results were very encouraging and suggest further that the measurement of facial muscle activity may be a potentially useful computer input signal, for example, for affective computing which can be seen as a future versatile interaction between the computer and the user.

Electromyography↗
PubMed2001

Inhibition of pericranial muscle activity, respiration, and heart rate enhances auditory sensitivity.

We investigated whether previously observed inhibition of pericranial electromyographic (EMG) activity, respiration, and heart rate during sensory intake processes improves auditory sensitivity. Participants had to detect weak auditory stimuli. We found that EMG activity in masticatory and lower facial muscles, respiration, and heart rate were more strongly inhibited when stimulus intensity was gradually lowered to threshold level whereas EMG of upper facial muscles progressively increased. Detection of near-threshold stimuli was inversely related to prestimulus EMG levels in masticatory and lower facial muscles. In two additional experiments, it was investigated whether steady, voluntary contractions negatively influence auditory sensitivity. As expected, contraction of zygomaticus produced an increase in auditory threshold in comparison with contraction of corrugator or first dorsal interosseus. It is concluded that attention to external stimuli is accompanied by quieting of those somatic activities that produce internal noise or are accompanied by impaired middle ear transmission of auditory stimuli.

Adolescent↗
PubMed2006

Role of the trigeminal nerve in regrowth of hypoglossal motoneurons after hypoglossal-facial anastomosis.

Conclusion. Functional recovery of facial muscles following hypoglossal-facial anastomosis (HFA) may be dependent not only on sensory information, relayed via the trigeminal nuclei to the hypoglossal nucleus, but also on extratrigeminal fibers, originating from the hypoglossal nucleus that travel in the infraorbital nerve (ION). This fact helps to explain the ability of hypoglossal neurons, after HFA, to induce contractions of muscles originally innervated from other nervous structures. Objective. The aim of the study was to better understand the role of the trigeminal nerve in reinnervation of facial muscles by hypoglossal motoneurons following HFA. Materials and methods. Central afferences of the ION were analyzed in rats by labeling the exposed nerve with horseradish peroxidase (HRP), whereas central organization of the efferent projections to the vibrissal area was analyzed by labeling the whisker pad muscles of the rat with a 5% solution of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (Dil) in N,N-dimethylformamide. Results. The results show that extratrigeminal fibers, originating in the hypoglossal nucleus, travel along the ION. Retrograde tracing applied to ION or injected into the whisker pad showed labeled neurons in the Pr5 nucleus and all Sp5 trigeminal subnuclei. Small labeled neurons (10-15 microm diameter; 10-12 neurons per section), were also found in the hypoglossal nucleus.

Anastomosis, Surgical↗
PubMed2005

The face of pain--a pilot study to validate the measurement of facial pain expression with an improved electromyogram method.

OBJECTIVE: The purpose of this pilot study was to establish the validity of an improved facial electromyogram (EMG) method for the measurement of facial pain expression. BACKGROUND: Darwin defined pain in connection with fear as a simultaneous occurrence of eye staring, brow contraction and teeth chattering. Prkachin was the first to use the video-based Facial Action Coding System to measure facial expressions while using four different types of pain triggers, identifying a group of facial muscles around the eyes. METHOD: The activity of nine facial muscles in 10 healthy male subjects was analyzed. Pain was induced through a laser system with a randomized sequence of different intensities. Muscle activity was measured with a new, highly sensitive and selective facial EMG. RESULTS: The results indicate two groups of muscles as key for pain expression. These results are in concordance with Darwin's definition. As in Prkachin's findings, one muscle group is assembled around the orbicularis oculi muscle, initiating eye staring. The second group consists of the mentalis and depressor anguli oris muscles, which trigger mouth movements. CONCLUSIONS: The results demonstrate the validity of the facial EMG method for measuring facial pain expression. Further studies with psychometric measurements, a larger sample size and a female test group should be conducted.

Electromyography↗
PubMed1984

On the origin of synkinesis in hemifacial spasm: results of intracranial recordings.

Recordings were made from facial muscles and the facial nerve near its entrance into the brain stem in patients with hemifacial spasm (HFS). The purpose of this study was to determine if the synkinesis commonly seen in patients with HFS could be linked to ephaptic transmission at the presumed site of the lesion (at the root entry zone (REZ) of the facial nerve). When the mandibular branch of the facial nerve was electrically stimulated, a response could be recorded from the orbicularis oculi muscles during the operation. The latency of the earliest response was 11.03 +/- 0.66 msec (mean response of seven patients +/- standard deviation (SD]. With equivalent stimulation a response could also be recorded from the facial nerve near the REZ; the latency of this response was 3.87 +/- 0.36 msec. Stimulation of the facial nerve at the same location yielded a response from the orbicularis oculi muscle, with a latency of 4.65 +/- 0.25 msec. The latency of the earliest response from the orbicularis oculi muscle to stimulation of the marginal mandibular branch of the facial nerve (11.3 msec) is thus larger than the sum of the conduction times from the points of stimulation of the marginal mandibular branch to the REZ of the facial nerve and from the REZ of the facial nerve to the orbicularis oculi muscle (8.52 +/- 0.38 msec). It is therefore regarded as unlikely that the earliest response of the orbicularis oculi muscle to stimulation of the mandibular branch of the facial nerve is a result of "crosstalk" in the facial nerve at a location near the REZ, and it seems more likely that HFS caused by injury of the facial nerve is a result of reverberant activity in the facial motonucleus, possibly caused by mechanisms that are similar to kindling.

Brain Stem↗
PubMed1985

Facial morphology and vibrissal movement in the golden hamster.

The major cranial vibrissae in the golden hamster can be moved in complex ways that suggest they are served by a finely controlled motor system. Movements are hypothesized to be the products of differential blood flow and pressure regulation in the sinus surrounding each vibrissal follicle, contractions of the striated facial muscles, and elastic rebound in the connective tissues. The vasculature contributes hydrostatic forces that erect the vibrissae slightly and distort their connective tissue bedding, rigidify the vibrissal capsules, thus forming firm bases of attachment for certain facial muscles, and theoretically provide a pressure plate around the follicle, important in lowering the firing thresholds of receptor endings. The facial muscles supply the major forces in erection and protraction of the vibrissae by acting on both the capsules and the connective tissue bedding. The connective tissues are organized into capsular and extracapsular systems that serve to stabilize the vibrissae and return them to initial rest positions. The slight movements of the genal vibrissa are the effects of vascular and connective tissue dynamics, the musculature being uninvolved. Wide angle movements of the supraorbital vibrissae are products of the vasculature and connective tissues, plus contractions of the Mm. orbicularis oculi and frontalis. Mystacial vibrissal movement is quite complex. The vasculature supplies a small degree of capsular erection and mystacial pad distortion, but primarily rigidifies the capsules. The bulk of erection and protraction is produced by the M. nasolabialis profundus (NLP) and the vibrissal capsular muscles (VCM). The NLP distorts the mystacial pad; the VCM tilt the capsules relative to the pad. Retraction is mainly accomplished by elastic rebound in the pad, this being aided in its extreme degrees by the Mm. nasolabialis and maxillolabialis. The Mm. nasolabialis superficialis and buccinator pars orbicularis oris help to spread the vibrissae into a dorsoventral fan and stabilize the mystacial pad during whisking.

Animals↗
PubMed2005

Comparative anatomy of the facial motor nucleus in mammals, with an analysis of neuron numbers in primates.

The facial motor nucleus (VII) contains motoneurons that innervate the facial muscles of expression. In this review, the comparative anatomy of this brainstem nucleus is examined. Several aspects of the anatomical organization of the VII appear to be common across mammals, such as the distribution of neuron types, general topography of muscle representation, and afferent connections from the midbrain and brainstem. Phylogenetic specializations are apparent in the proportion of neurons allocated to the representation of subsets of muscles and the degree of differentiation among subnuclei. These interspecific differences may be related to the elaboration of certain facial muscles in the context of socioecological adaptations such as whisking behavior, sound localization, vocalization, and facial expression. Furthermore, current evidence indicates that direct descending corticomotoneuron projections in the VII are present only in catarrhine primates, suggesting that this connectivity is an important substrate for the evolution of enhanced mobility and flexibility in facial expression. Data are also presented from a stereologic analysis of VII neuron numbers in 18 primate species and a scandentian. Using phylogenetic comparative statistics, it is shown that there is not a correlation between group size and VII neuron number (adjusted for medulla volume) among primates. Great apes and humans, however, display moderately more VII neurons that expected for their medulla size.

Anatomy, Comparative↗
PubMed2006

Facial paralysis.

Detailed knowledge of embryology, anatomy, and function of the facial nerve is essential in treating the devastating functional, aesthetic, and psychological sequelae of facial paralysis. Two basic factors influence the method of repair and the subsequent outcome of the effort to combat facial paralysis. First is the availability of a viable proximal nerve stump which can be used as the source for motor axons, and which is related to the level of the injury. Second is the duration of the paralysis, which will dictate the possibility of reinnervating the facial muscles. Early restoration of nerve continuity, and therefore reestablishment of the neuromuscular junction and preservation of the function of the facial muscles, lead to superior functional and aesthetic rehabilitation. Secondary reconstruction, after the establishment of atrophy of the motor endplates of the facial muscles, is possible with nerve grafts and microsurgical free functional muscle transfer. These techniques, although not perfect, greatly improve aesthetic balance and alleviate the functional and psychological implications of the paralysis.

Facial Nerve↗
PubMed1989

[Progressive myositis ossificans--a case report].

A case of myositis ossificans in a 28 year old male is reported. He had been found to have ossification of the right sternocleidomastoid muscle at birth. Subsequently both thighs, abdominal muscles of the right side and facial muscles on both sides were similarly affected. X-ray findings, biopsied specimens and biochemical changes were in accord with those reported in the literature, though involvement of facial muscles and the heart had not been previously reported. The presence of several congenital malformations gives support to the important role of heredity in the pathogenesis of this disease. EHDB brought some relief in this case, and may be of prophylactic value in the prevention of ossification due to postoperative trauma of a planned temporo-mandibular operation.

Adult↗
PubMed2002

Comparative anatomy of the buccinator muscle in cat (Felis domestica).

Published descriptions of the buccinator muscle of the cat (Felis domestica) differ from those for the same muscle in other mammals. Only an oral component of the muscle has been described in cats, not a buccal part. The purpose of this study was to identify the buccinator muscle in the cat and report on its anatomical features in detail. Dissections of the facial muscles were carried out on 12 specimens of adult cats (6 males and 6 females) that had been fixed with 10% formalin. We then observed the facial muscles and traced their innervations, arteries, and veins under a binocular microscope. The buccinator muscle in the cat was identified underneath an orbicularis oris, arising from the lower buccal membrane and from the molar region of the alveolar border of the mandible. It was about 3 mm wide at its origin, 4 mm wide at its insertion, and about 11 mm in length from origin to insertion. This contrasts with humans, in whom the muscle arises not only from the mandible, but also from the maxilla. Apart from this difference, this muscle in cats displays the following similarities to the buccinator muscle of other mammals: 1) it is innervated by the facial nerve; 2) it supports the buccal membrane; 3) it seems to insert into the modiolus; 4) its bundles run antero-posteriorly; 5) the posterior part of the muscle is located medially to the masseter muscle; 6) the parotid duct, facial nerve, artery, and vein run lateral to the muscle; 7) it is located deeper than other facial muscles; and 8) the buccal nerve runs on its surface. These relationships are spatially similar to those of the buccinator muscle in mammals. This muscle may aid in mastication, including suckling, and in expelling air forcibly, like the buccinator in humans.

Animals↗
PubMed1990

Corticobulbar projections to upper and lower facial motoneurons. A study by magnetic transcranial stimulation in man.

To investigate the human corticofacial projections, we recorded the compound motor potentials and single motor unit potentials evoked by magnetic transcranial stimulation, in the frontalis and lower facial muscles of healthy subjects. Potentials secondary to activation of the corticobulbar tract were contralateral in lower and bilateral in upper facial muscles. Even though the latency of responses was longer than would be expected for direct cortico-motoneuronal connections, these cannot be excluded either for lower or upper facial motoneurons.

Adult↗
PubMed1984

Pulmonary changes induced by frontal EMG training.

Earlier research suggested that the effects of facial muscle tension changes on other responses are not widespread but limited to a rather narrow set of pulmonary events. Further evidence in support of the specificity of the facial muscle-pulmonary relationship was provided in the present study by monitoring changes in several responses as a function of muscle tension training. Feedback training for increases and decreases in muscle tension at both facial and limb muscle sites was given to adult males. The effects of these manipulations on PEFR, RR, and HR were examined. Increases in facial muscle tension resulted in PEFR decreases whereas increases in limb muscle tension did not. Decreases in facial muscle tension were not observed as a function of training and no PEFR changes resulted from these conditions. Neither RR nor HR were related to the facial EMG changes observed during feedback training. These observations demonstrated the specificity inherent in the relationship between facial muscle tension and PEFR, and lent support to the hypothesis that these two responses are linked reflexively.

Adolescent↗
PubMed1994

Monosynaptic innervation of facial motoneurones by neurones of the parvicellular reticular formation.

In order to determine whether neurones in the parvicellular reticular formation are in direct synaptic contact with motoneurones innervating facial muscles, a combined retrograde and anterograde transport study was carried out in the rat. Animals received injections of the retrograde tracer cholera toxin B conjugated to horseradish peroxidase into facial muscles and of the anterograde tracer biocytin into the parvicellular reticular formation. The facial motor nucleus was then examined for anterograde and retrograde labelling in the light and electron microscopes. Retrogradely labelled neurones were found in the facial motor nucleus with a distribution that was dependent on the muscles injected. Terminals anterogradely labelled with biocytin from the parvicellular reticular formation was observed in the motor nucleus amongst the retrogradely labelled neurones. At the electron microscope, the retrogradely labelled cells were found to receive input from unlabelled terminals and from terminals that were anterogradely labelled from the injections of biocytin in the parvicellular reticular formation. The labelled terminals were 1-2 microns in diameter at the active zone and packed with spherical vesicles. They formed both symmetrical and asymmetrical synapses with their labelled or unlabelled targets. It is concluded that neurones in the parvicellular reticular formation form direct synaptic contact with motoneurones of facial muscles. This may represent a pathway by which the basal ganglia can directly influence orofacial movement, as the substantia nigra is known to project to that part of the reticular formation.

Animals↗
PubMed2002

Smiling, frowning, and autonomic activity in mildly depressed and nondepressed men in response to emotional imagery of social contexts.

The study examined self-reported emotion and facial muscle and autonomic activity of depressed and nondepressed men in response to the social context of emotional situations. 20 university men, assessed on the Beck Depression Inventory, were asked to imagine happy and sad situations with and without visualizing other people. No differences were found between men classified as depressed and nondepressed on self-reported emotion and facial muscle activity. Smiling did not show differences between social contexts although self-reported happiness was increased during happy-social compared to happy-solitary imagery. Adjusting smiling for social context differences in happiness showed less smiling during happy-social than during happy-solitary imagery. In contrast, self-reported sadness and frowning were greater during sad-social compared to sad-solitary imagery. No differences between social contexts were found when frowning was adjusted for social context differences in sadness. Depressed-scoring men showed higher mean heart rate during sad-social than sad-solitary imagery whereas nondepressed-scoring men showed higher mean heart rate during happy social compared to happy-solitary imagery. The results indicate that men may frown more when sad but generally do not smile more during happy-social imagery, independent of depression. Depressed mood may affect heart rate during sad imagery but may not alter facial muscle activity and self:reported emotion in men.

Adult↗