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PubMed2004

Effects of mastic resin and its essential oil on the growth of proteolytic Clostridium botulinum.

Studies were done to determine the effect of mastic resin and its essential oil, alone and in conjunction with ethanol, on the growth of proteolytic strains of Clostridium botulinum in media, and on neurotoxin production in challenge studies with English-style crumpets. Preliminary studies, using a spot-on-the-lawn method, indicated that high levels of mastic resin in ethanol ( approximately 8% w/w) were required for complete inhibition of all strains of C. botulinum tested, but mastic resin in ethanol had a greater anti-botulinal effect than ethanol alone. However, only low levels of mastic oil ( approximately 0.3% v/v) were required for inhibition of proteolytic strains of C. botulinum. Both studies showed a strain specific inhibition, with C. botulinum type A strains being more sensitive to mastic resin and its essential oil than type B strains. However, mastic resin in ethanol proved to be more effective when used as a vapor phase inhibitor applied to cotton pads and placed inside inoculated plates than when added directly to media. While both mastic resin and its essential oil inhibited the growth of proteolytic strains of C. botulinum in vitro, they failed to inhibit neurotoxin production in challenge studies with C. botulinum in English-style crumpets.

Botulinum Toxins↗

PubMed2005

[CT and MRI features of diseases involving masticator spaces].

OBJECTIVE: This is a study on the CT and MRI features of diseases involving the masticator spaces; the purpose is to improve the diagnostic accuracy. METHODS: Fifty-seven cases involving the masticator spaces were collected, among which, 11 cases were originated from the masticator space, another 46 cases were secondary invasion from the adjacent structures, including 18 cases from the buccal mucosa, 10 from the nasopharynx, 5 from the gingiva, 3 from the parotid gland, 6 from the maxillary sinus, 1 from the intracranial location, 2 from the palate and 1 from the orbit. The CT and MRI features of the masticator space involvement were analysed. RESULTS: Masticator space involvement is visualized on CT and MRI as effacement of the fat plane, swelling of the masticatory muscles, and erosion of the mandibular ramus. Disease from surrounding structures can invade the masticator space via the pterygopalatine fossa, the buccal space immediately anterior to the ramus, the foramen ovale, or by way of direct invasion. CONCLUSION: Masticator space involvement is not uncommon in the maxillofacial diseases, which must be noticed in the imaging diagnosis.

Adolescent↗

PubMed2006

Gum mastic inhibits the expression and function of the androgen receptor in prostate cancer cells.

Accumulating evidence suggests that the androgen receptor (AR) may play an important role in the development and progression of prostate cancer. To find new, useful compounds that effectively may attenuate the function of AR in prostate cancer cells, the authors investigated the effect of gum mastic, a natural resin, on AR activity. An androgen-responsive prostate cancer cell line LNCaP was used as a model for this study. Gene transfer, reverse transcriptase-polymerase chain reaction analysis, electrophoretic mobility shift assay, and Western blot analysis were used to test the effect of gum mastic on the expression and function of the AR. To demonstrate the inhibitory effect of gum mastic on the function of the AR, the expression of androgen-regulated genes, including prostate-specific antigen (PSA), human kallikrein 2 (hK2), and NKX3.1 were measured. In addition, transient transfection assays with the PSA promoter and the AR promoter also were used to test the effects of mastic. The results showed that gum mastic inhibited the expression of the AR at the transcriptional level, resulting in the down-regulation of both AR messenger RNA and protein levels. Therefore, the function of the AR was inhibited, as reflected by the reduced expression of NKX3.1 and PSA and by androgen-stimulated growth. Because gum mastic exhibited a strong in vitro potency to attenuate the expression and function of the AR, further investigation will be required to determine whether this naturally occurring substance has in vivo potency to inhibit prostate cancer development.

Androgens↗

PubMed2003

Monotherapy with mastic does not eradicate Helicobacter pylori infection from mice.

OBJECTIVE: To determine the ability of mastic monotherapy to eradicate Helicobacter pylori infection from mice. MATERIALS AND METHODS: The susceptibility of H. pylori SS1 to mastic was assessed by broth dilution determination of the MIC and MBC. Mice were inoculated intragastrically with either a suspension of H. pylori SS1 (n = 70) or brain-heart infusion broth alone (n = 10). Mice were given antimicrobial chemotherapy 4 weeks after infection and were administered the mouse equivalent of either 2 g of mastic twice daily for 7 days or a triple therapy regimen containing the mouse equivalent of 400 mg of metronidazole, 250 mg of clarithromycin and 20 mg of omeprazole twice daily for 7 days. Mice were killed either immediately or 1 month after the completion of treatment, and their stomachs cultured for H. pylori. RESULTS: The mastic MIC and MBC of H. pylori SS1 were 7.80 and 31.25 mg/L, respectively. The triple therapy regimen eradicated infection from 19 of 20 SS1-infected mice. Mastic failed to eradicate infection from any of the 18 SS1-infected mice (P < 0.001) and there was no signifi- cant reduction in gastric bacterial load in mice treated with this regimen. CONCLUSION: Despite reported beneficial effects in ulcer patients and the good in vitro activity of mastic against H. pylori, this compound is unable to eradicate H. pylori infection from mice.

Animals↗

PubMed2003

Role of mastication and swallowing in the control of autonomic nervous activity for heart rate in different postures.

Mastication and swallowing increase the heart rate, and posture change and respiration also modulate the heart rate. To clarify the role of mastication and swallowing in the modulation of the autonomic nervous activity, we investigated how they interact with modulation of the heart rate by changing body positions and respiration in young healthy subjects. R-R intervals of electrocardiogram at rest were significantly changed with different body positions, compared with supine and standing. A net shortening by mastication of a chewing gum base was similar in various postures. Respiration induced a periodic change in the R-R intervals, depending on the body postures, but mastication did not markedly change them in each posture. Dry swallowing at rest and spontaneous swallowing during the mastication in the sitting position induced a similar transient shortening and suppressed the respiration-induced changes after the swallowing. The net transient shortening by dry swallowing at rest was similar in the different postures. These results suggest that signals from mastication and swallowing are summated with those from body positions and respiration for shortening the R-R intervals and that signals from swallowing suppress the respiration-induced periodic changes.

Adult↗

PubMed1994

Control of jaw orientation and position in mastication and speech.

1. The kinematics of sagittal-plane jaw motion were assessed in mastication and speech. The movement paths were described in joint coordinates, in terms of the component rotations and translations. The analysis focused on the relationship between rotation and horizontal translation. Evidence was presented that these can be separately controlled. 2. In speech, jaw movements were studied during consonant-vowel utterances produced at different rates and volumes. In mastication, bolus placement, compliance, and size as well as chewing rate were manipulated. Jaw movements were recorded using the University of Wisconsin X-ray microbeam system. Jaw rotation and translation were calculated on the basis of the motion of X-ray tracking pellets on the jaw. 3. The average magnitudes of jaw rotation and translation were greater in mastication than in speech. In addition, in speech, it was shown that the average rotation magnitude may vary independent of the horizontal translation magnitude. In mastication, the average magnitude of vertical jaw translation was not dependent on the magnitudes of jaw rotation or horizontal jaw translation. 4. The magnitude of rotation and horizontal jaw translation tended to be correlated when examined on a trial by trial basis. Some subjects also showed a correlation between jaw rotation and vertical jaw translation. However, the proportion of variance accounted for was greater for all subjects in the case of rotation and horizontal translation. 5. Joint space paths in both mastication and speech were found to be straight. The pattern was observed at normal and fast rates of speech and mastication and for loud speech as well. Straight line paths were also observed when subjects produced utterances that had both the syllabic structure and the intonation pattern of speech. The findings suggest that control may be organized in terms of an equilibrium jaw orientation and an equilibrium jaw position. 6. Departures from linearity were also observed. These were typically associated with differences during jaw closing in the end time of rotation and translation. Start time differences were not observed in jaw closing and the movement paths were typically linear within this region.

Computer Graphics↗

PubMed2006

Evaluation of the effects of mastication and swallowing on gastric motility using electrogastrography.

OBJECTIVES: The influence of mastication and swallowing on gastric motor function was evaluated by electrogastrography (EGG) and abdominal ultrasonography. METHODS: The subjects were 30 elderly patients with tubal feeding without mastication and swallowing (T group) and 30 elderly controls who processed food by mastication and swallowing (C group). Gastric motor function was percutaneously examined before and after the ingestion of 250 ml of a liquid diet using an electrogastrograph (NIPRO EGG, A and D, Tokyo, Japan). The cross-sectional area of the gastric antrum was measured at 1 and 30 min after the start of ingestion of the liquid diet by external ultrasonography of the abdomen, and the gastric excretion function was evaluated. Furthermore, the spectral analysis of heart rate variability was performed using Holter electrocardiograms before and after ingestion. The low frequency power (LF power, 0.04-0.15 Hz), high frequency power (HF power, 0.15-0.40 Hz), and the LF/HF ratio were determined. RESULTS: The peak amplitude at 3 cycles per minute (cpm) was significantly increased after ingestion in the C and T groups (p<0.05), and the ratio of increase was significantly lower in the T group (p<0.05). The mean amplitude for the brady-gastria and tachy-gastria was significantly higher in the T group than in the C group (p<0.05). The gastric excretion function, as evaluated by external ultrasonography of the abdomen, was significantly lower in the T group than in the C group (p<0.05). An analysis of heart rate variability demonstrated that the HF power, a parameter of parasympathetic activity, after ingestion was significantly higher in the C group than in the T group (p<0.05). No changes in LF power or LF/HF ratio, parameters of sympathetic activity, were induced by ingestion in either the C or T groups. CONCLUSIONS: The parasympathetic nerve dominantly controls gastric motor function, but autonomic nervous activity is reduced in patients who are unable to masticate and swallow food, resulting in adverse effects on gastric motor function and excretion function. Mastication and swallowing not only prepare food for passage from the oral cavity to the esophagus but are also important in terms of subsequent events that occur in stomach. It has been proposed that autonomic nervous activity might be involved in mastication and swallowing.

Abdomen↗

PubMed1990

Particle size reduction during initial mastication of forages by dairy cattle.

Four experiments were conducted with dairy cattle to determine the effects of initial feed particle size and moisture content on particle size of ingested masticates. Three mature Holstein cows were used in either latin square or Youden square designs. Samples of masticated and ingested boli were collected at the cardiac opening through a ruminal fistula between 0 and 5, 5 and 10 and 10 and 15 min after meal initiation. In Exp. 1, masticate log mean particle sizes (LMPS) (ln microns, log normal distribution) were 3.50, 3.53 and 3.50 for corn silage, fine-chopped alfalfa haylage and coarse-chopped alfalfa haylage, respectively. In Exp. 2, boli LMPS for ground, chopped and long alfalfa hay were 3.11, 3.76 and 4.09, respectively. Boli LMPS in Exp. 3 for ground, chopped and long timothy hay were 2.93, 3.12 and 3.03, respectively. Exp. 4 compared the effect of addition of water to produce 30%, 47%, 64% and 82% DM in chopped alfalfa hay. Boli LMPS were 3.66, 3.56, 3.64 and 3.68 for the respective alfalfa hay DM contents. Feed LMPS was not reduced during mastication in Exp. 4, nor were there differences in LMPS due to time after feeding. Boli LMPS was affected by feed particle size of alfalfa hay, but there was no effect of feed particle size on masticate particle size in timothy hay. The magnitude of particle size reduction during mastication appears to be dependent on forage type and is not dependent totally on initial feed particle size and DM content of forages.

Animal Feed↗

PubMed2003

[Effect of unilateral mastication on the remodeling of the glenoid fossae in Wistar rats].

OBJECTIVE: To investigate the effect of unilateral mastication on glenoid fossae by means of animal experiment. METHODS: An animal model of unilateral mastication was established by extracting right mandibular molars of Wistar rats. The rats were sacrificed in different period to examine the location changes of glenoid fossae through sagittal and horizontal plane. RESULTS: The anterior points of glenoid fossae in non-masticatory side of experimental groups were more anterior than those in masticatory sides. The anterior points of the glenoid fossae of non-masticatory sides in experimental groups were more anterior than those of the same sides in the control groups after inducing unilateral mastication for two and four months. After inducing unilateral mastication for two and four months, the anterior and the posterior points of the glenoid fossae of non-masticatory sides in experimental groups became closer to the midline by comparison with masticatory sides as well as the same sides in control groups. Locations of glenoid fossae in masticatory sides showed no changes in comparison with the same side of the control groups. CONCLUSION: The forward and inward remodeling of the glenoid fossae can be observed after unilateral mastication was induce to the non-masticatory sides of experimental rats. It is concluded that unilateral mastication might be one of the etiologic factor of temporomandibular joint disorders.

Alveolar Process↗

PubMed2006

Mastic oil from Pistacia lentiscus var. chia inhibits growth and survival of human K562 leukemia cells and attenuates angiogenesis.

Mastic oil from Pistacia lentiscus var. chia, a natural plant extract traditionally used as a food additive, has been extensively studied for its antimicrobial activity attributed to the combination of its bioactive components. One of them, perillyl alcohol (POH), displays tumor chemopreventive, chemotherapeutic, and antiangiogenic properties. We investigated whether mastic oil would also suppress tumor cell growth and angiogenesis. We observed that mastic oil concentration and time dependently exerted an antiproliferative and proapoptotic effect on K562 human leukemia cells and inhibited the release of vascular endothelial growth factor (VEGF) from K562 and B16 mouse melanoma cells. Moreover, mastic oil caused a concentration-dependent inhibition of endothelial cell (EC) proliferation without affecting cell survival and a significant decrease of microvessel formation both in vitro and in vivo. Investigation of underlying mechanism(s) demonstrated that mastic oil reduced 1) in K562 cells the activation of extracellular signal-regulated kinases 1/2 (Erk1/2) known to control leukemia cell proliferation, survival, and VEGF secretion and 2) in EC the activation of RhoA, an essential regulator of neovessel organization. Overall, our results underscore that mastic oil, through its multiple effects on malignant cells and ECs, may be a useful natural dietary supplement for cancer prevention.

Angiogenesis Inhibitors↗

PubMed2001

[A case of chronic masticator space abscess].

Different neoplasms and infections are known to involve the masticator space, but pathological diagnosis and treatment of these lesions are not always simple due to anatomical complexity. We treated a 66-year-old man with an abscess in the nasopharyngeal masticator space. Physical and CT findings resembled those of neoplastic lesion because the onset dated back 5 years and the patient was lacking in notable signs of infection. Surgery through the maxillary sinus to the lesion enabled us to confirm its pathology and drain pus, with subsequent cure. We noted periodontal infection of the mandibular molars accompanied with osteomyelitis as a cause of this abscess, so infected molars were extracted 13 days after surgery. The infection had spread upward along the mastication muscles, resulting in an abscess in both the upper masseter muscle and the lower temporalis muscle. Based on a review of the literature, most abscesses in the masticator space originate from the mandibular molar, while the most impressive physical finding varied between the submandibular region and temporal fossa, as did its acute or chronic clinical course. Such clinical manifestations appear to reflect the pattern of infection spread along the muscles of mastication and a pattern involving adjacent spaces. We emphasize diagnostic significance when assessing findings for each mastication muscle and mandibular bone depicted using computed tomography, magnetic resonance imaging, and bone-scan technetium.

Abscess↗

PubMed1999

A model of temporomandibular joint function in anthropoid primates based on condylar movements during mastication.

The hypothesis that the shape of the bony temporomandibular joint (TMJ) is functionally related to sagittal sliding of the condyle during mastication is tested, and a model of the relation of sagittal sliding to mandibular size, TMJ shape, and diet is developed. Sagittal sliding is defined as fore-aft motion of the condyle during mandibular translation and/or angular rotation. Ascending ramus height is used as a structural correlate of the distance between the condyle and the mandibular axis of rotation (CR). Cineradiographic data on sagittal sliding and gape during mastication in Ateles spp., Macaca fascicularis, Papio anubis, and Pan troglodytes in conjunction with comparative data on mandibular size and TMJ shape are used to evaluate the hypothesis. The results show that 1) linear and angular gape are highly positively correlated with sagittal sliding, 2) pure mandibular translation is rare during mastication, 3) the CR is rarely if ever located at the condyle during mastication, 4) angular gape should be standardized in interindividual comparisons of sagittal sliding, and 5) the height of the ascending ramus (and by inference the CR-to-condyle distance) is highly positively correlated with absolute sagittal sliding. Sagittal sliding relative to the length of the articular eminence was the variable used to explore the relation between TMJ shape and sliding. This variable standardized absolute sagittal sliding relative to joint size. The relative depth and orientation of the articular eminence were not correlated with relative sagittal sliding. The anteroposterior curvature of the condyle was highly negatively correlated with relative sagittal sliding. Flat condyles are associated with large amounts of relative sagittal sliding. A flat condyle increases joint contact area, which reduces joint stress. A flat condyle also increases joint congruence, and this may facilitate the combined sliding and rolling motion of the condyle when the sliding motion is relatively large. The shape of the entoglenoid process was also positively correlated with relative sagittal sliding. A relatively large entoglenoid process may help to guide sagittal sliding and prevent excessive mediolateral sliding of the condyle. The functional model makes a number of predictions about the correlations between food consistency and food object size, mandibular size, TMJ shape, and sagittal sliding of the condyle during mastication and incision.

Animals↗

PubMed1987

Loading patterns and jaw movements during mastication in Macaca fascicularis: a bone-strain, electromyographic, and cineradiographic analysis.

Rosette strain gage, electromyography (EMG), and cineradiographic techniques were used to analyze loading patterns and jaw movements during mastication in Macaca fascicularis. The cineradiographic data indicate that macaques generally swallow frequently throughout a chewing sequence, and these swallows are intercalated into a chewing cycle towards the end of a power stroke. The bone strain and jaw movement data indicate that during vigorous mastication the transition between fast close and the power stroke is correlated with a sharp increase in masticatory force, and they also show that in most instances the jaws of macaques are maximally loaded prior to maximum intercuspation, i.e. during phase I (buccal phase) occlusal movements. Moreover, these data indicate that loads during phase II (lingual phase) occlusal movements are ordinarily relatively small. The bone strain data also suggest that the duration of unloading of the jaw during the power stroke of mastication is largely a function of the relaxation time of the jaw adductors. This interpretation is based on the finding that the duration from 100% peak strain to 50% peak strain during unloading closely approximates the half-relaxation time of whole adductor jaw muscles of macaques. The EMG data of the masseter and medial pterygoid muscles have important implications for understanding both the biomechanics of the power stroke and the external forces responsible for the "wishboning" effect that takes place along the mandibular symphysis and corpus during the power stroke of mastication. Although both medial pterygoid muscles reach maximum EMG activity during the power stroke, the activity of the working-side medial pterygoid peaks after the balancing-side medial pterygoid. Associated with the simultaneous increase of force of the working-side medial pterygoid and the decrease of force of the balancing-side medial pterygoid is the persistently high level of EMG activity of the balancing-side deep masseter (posterior portion). This pattern is of considerable significance because the direction of force of both the working-side medial pterygoid and the balancing-side deep masseter are well aligned to aid in driving the working-side lower molars across the upper molars in the medial direction during unilateral mastication.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed2006

Brainstem circuits that control mastication: do they have anything to say during speech?

UNLABELLED: Mastication results from the interaction of an intrinsic rhythmical neural pattern and sensory feedback from the mouth, muscles and joints. The pattern is matched to the physical characteristics of food, but also varies with age. There are large differences in masticatory movements among subjects. The intrinsic rhythmical pattern is generated by an assembly of neurons called a central pattern generator (CPG) located in the pons and medulla. The CPG receives inputs from higher centers of the brain, especially from the inferio-lateral region of the sensorimotor cortex and from sensory receptors. Mechanoreceptors in the lips and oral mucosa, in muscles, and in the periodontal ligaments around the roots of the teeth have particularly powerful effects on movement parameters. The central pattern generator includes a core group of neurons with intrinsic bursting properties, as well as a variety of other neurons that receive inputs from oral and muscle spindle afferents. Reorganization of subpopulations of neurons within the CPG underlies changes in movement pattern. In addition to controlling motoneurons supplying the jaw, tongue, and facial muscles, the CPG also modulates reflex circuits. It is proposed that these brainstem circuits also participate in the control of human speech. LEARNING OUTCOMES: Readers will be able to: (1) describe the general location and function of the central pattern generator for mastication, (2) identify the primary nuclei involved in the central pattern generator for mastication, (3) describe the general interactions among the central pattern generators of speech, mastication, respiration, and locomotion, and (4) compare/relate the brainstem systems controlling mastication and speech.

Animals↗

PubMed2006

Chios mastic gum modulates serum biochemical parameters in a human population.

INTRODUCTION: Current research suggests that Chios mastic (Pistacia lentiscus var. chia) possesses beneficial (antimicrobial, antioxidant, hepatoprotective) properties. This study aims to assess its effects on cardiologic and hepatic biochemical indices of human subjects. MATERIALS AND METHODS: Subjects (n=133, aged over 50) were randomly assigned to two groups, the first (high-dose group) ingesting daily 5g of mastic powder and the second receiving daily a Chios mastic solution (low-dose group). Serum biochemical parameters were determined on a monthly basis for an 18-month (high-dose group) and a 12-month (low-dose group) follow-up period. Generalized least squares random-effects linear regression was performed. RESULTS: The group ingesting Chios mastic powder (high-dose group) exhibited a decrease in serum total cholesterol, LDL, total cholesterol/HDL ratio, lipoprotein (a), apolipoprotein A-1, apolipoprotein B (apoB/apoA-1 ratio did not change), SGOT, SGPT and gamma-GT levels; in the second (low-dose) group, glucose levels decreased in males. DISCUSSION: Chios mastic powder could have a hepatoprotective/cardioprotective role in vivo in humans.

Alanine Transaminase↗

PubMed2005

Coordination of cranial motoneurons during mastication.

Mastication is the first stage of digestion and involves several motor processes such as food intake, intra-oral food transport, bolus formation and chewing in its broad sense. These complicated motor functions can be accomplished by the well-coordinated activities in various cranial motoneurons innervating the jaw, hyoid, tongue and facial muscles. The brainstem masticatory central pattern generator (CPG) plays a crucial role in generating basic activity patterns of these cranial motoneuron groups. However, descending inputs from higher brain (e.g., cerebral cortex) and mastication-generated peripheral sensory inputs also play important roles in modulating the activity pattern of each motoneuron so that the final motor outputs fit the environmental demand. In this review, we focus on the coordination of the trigeminal, facial and hypoglossal motoneurons during mastication. We first summarize findings showing the activity patterns of muscles innervated by these motoneurons during natural mastication, and then discuss the possible neural mechanisms underlying their coordinated activities during mastication.

Animals↗

PubMed1999

Variations in human masseter and temporalis muscle activity related to food texture during free and side-imposed mastication.

Adjustments of mastication to food texture have been examined in various studies, but the notion of food texture is often ill defined and usually assessed in terms of hardness. The goal of this study was to examine the pattern of activity in masseter and temporalis muscles during mastication of different food samples with known textural properties and to determine the interindividual variability. Electromyograms were recorded from the right and left masseter and temporalis muscles in 36 young adults during 'free-style' and side-imposed mastication. Five different types of food with known rheological properties were used. Both temporalis and masseter activity increased with increased stress at maximum strain of the chewed samples. A power function optimally described the relation between muscle work per chew and the mechanical measurements of food; this confirmed that the masticatory process is adjusted to accommodate to food texture. Temporalis muscle activity was more influenced by food texture than was masseter muscle activity. Less muscle work was needed to prepare the food bolus for swallowing during free-style mastication. However, 25% of the participants showed no differences between unilateral side-imposed mastication and 'free-style', suggesting that they might have greater chewing efficiency on one side.

Adult↗

PubMed2002

Effects of reversible bilateral inactivation of face primary motor cortex on mastication and swallowing.

The effects of reversible cold block-induced bilateral inactivation of the face primary motor cortex (face MI) on mastication and swallowing were studied in awake monkeys. A warm or cold alcohol-water solution was pumped through thermodes placed bilaterally on the dura overlying the intracortical microstimulation-defined face MI while the monkey chewed and swallowed food during pre-cool (thermode temperature 37 degrees C), cold block (4 degrees C), and post-cool (37 degrees C) sessions. Vertical and horizontal jaw movements and electromyographic (EMG) activity of several muscles were monitored. Each masticatory sequence was divided into three masticatory phases (i.e. food preparatory, rhythmic chewing, preswallow). The cold block markedly affected the ability of the monkey to carry out mastication although it did not prevent mastication from occurring. The masticatory deficit was characterized by a significant elongation of the total masticatory time, including in particular elongation of the food preparatory phase. The coordination of the jaw- and tongue-muscle activities was severely disrupted during the food preparatory phase. Face MI cold block also significantly affected the duration of some masticatory-related EMG activities and had some limited effects on the temporal relationships of the EMG activities during mastication. Although cold block significantly affected the duration and some EMG parameters of the preswallow phase, it had no significant effect on swallow duration or the EMG parameters during swallowing. These findings provide further evidence that the primate face MI plays a critical role in the regulation of mastication and that it plays a role in the preparation for swallowing.

Animals↗