Task-dependence of Jaw Elevator and Depressor                Co-activation

Proeschel, Peter; J, Raum

doi:10.1177/154405910308200809

Cited by 18 publications

(14 citation statements)

References 19 publications

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“…Indeed, such limitations have been described for the human stretch reflex in various muscles (Wolf and Segal 1996;Wolpaw 1983;Wolpaw et al 1983). Finally, incomplete suppression may be due to the fact that the digastric motor neurons are not actively hyperpolarized during jaw closing, and a peripherally evoked reflex activation of these would serve to increase the overall stiffness of the jaw system and support better contact and control of the morsel as it cracks (Goldberg et al 1982;Proeschel and Raum 2003;Türker 2002;Yoshida 1998).…”

Section: Discussionmentioning

confidence: 99%

Biting intentions modulate digastric reflex responses to sudden unloading of the jaw

Johansson

Pruszynski

Edin

et al. 2014

Journal of Neurophysiology

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Reflex responses in jaw-opening muscles can be evoked when a brittle object cracks between the teeth and suddenly unloads the jaw. We hypothesized that this reflex response is flexible and, as such, is modulated according to the instructed goal of biting through an object. Study participants performed two different biting tasks when holding a peanut half stacked on a chocolate piece between their incisors. In one task, they were asked to split the peanut half only (single-split task), and in the other task, they were asked to split both the peanut and the chocolate in one action (double-split task). In both tasks, the peanut split evoked a jaw-opening muscle response, quantified from electromyogram (EMG) recordings of the digastric muscle in a window 20-60 ms following peanut split. Consistent with our hypothesis, we found that the jaw-opening muscle response in the single-split trials was about twice the size of the jaw-opening muscle response in the double-split trials. A linear model that predicted the jaw-opening muscle response on a single-trial basis indicated that task settings played a significant role in this modulation but also that the presplit digastric muscle activity contributed to the modulation. These findings demonstrate that, like reflex responses to mechanical perturbations in limb muscles, reflex responses in jaw muscles not only show gain-scaling but also are modulated by subject intent.

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Section: Discussionmentioning

confidence: 99%

Biting intentions modulate digastric reflex responses to sudden unloading of the jaw

Johansson

Pruszynski

Edin

et al. 2014

Journal of Neurophysiology

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“…However, compared with the maximum possible level of digastrics activity, it was still proportionally small. Depressor counteraction could have only a minor influence on the generation of surplus muscle activity in chewing [13]. Using EMG to analyze chewing force alone, an overestimation of the chewing force may occur [14].…”

Section: Mastication and Food Characteristicsmentioning

confidence: 97%

“…It was postulated, that a coactivation of jaw opening muscles during the masticatory power stroke provokes an increased elevator activity [13]. Digastric muscle coactivation during elevator peak effort was significantly higher in chewing than in isometric biting.…”

Section: Mastication and Food Characteristicsmentioning

confidence: 99%

A novel standard food model to analyze the individual parameters of human mastication

Slavicek

Soykher²,

Gruber

et al. 2009

J. Stomat. Occ. Med.

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Introduction: The aim of this project was to develop a standard food model, which can be used not only in experimental settings, but also in clinical diagnosis. On the basis of the findings of a systematic literature search, an elastic food model was created with the aim of standardizing the size and the elastic properties. Three different eatable jellied products were chosen, created by changing the amount of gelatin (260 blooms) related to the total mass of the standard jellied food. The different hardness were classified into soft, medium, and hard, flavored identically, but stained with different colors: soft -green, medium -yellow, hard -red. A cylindrical form was chosen, with a height of 1 cm and a diameter of 2 cm. A standard protocol for analyzing chewing patterns in men was developed.Material and method: A case series of 6 participants (three males, mean age 39, range from 17-51 years; three females, mean age 30, range 17-52) was performed, using the developed standard protocol as described in this article. CADIAX diagnostic was used for the recording of the chewing cycles using a standard paraocclusal clutch, individualized with self-curing temporary material. Working side and nonworking side chewing dynamics were recorded and analyzed. Adverse Event reporting was performed.Results: All participants correctly identified the different hardness of the new jellied elastic standard food model. All participants were able to perform a single-sided mastication on the right and on the left side as well as repeated shifts from one side to the other. The chewed and crushed jellies could be collected after the recording. The chewing cycles were performed in an adequate range because of the size of the standard food model.Conclusion: The newly developed standard food model showed the capability to serve to analyze human mastication in experimental settings. In addition, strength and size of the newly developed standard food model load the masticatory system to an extent that it should be possible to disclose subclinical symptoms of the patient within a short time of examination. The diagnostic procedure of temporo-mandibular disorder (TMD) should be endorsed by the new method. The condylographic data, created by a standardized protocol, should have the ability to enhance the clinical functional analysis of patients previous to restorative dental procedures.

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“…A hypothetical model was used: simultaneous activation of the jaw openers during mastication leads to additional activation of the muscles involved in closing the jaw [73,74]. During mastication, additional and simultaneous activation of the digastric muscle was much more pronounced during closure than it is in isometric tension.…”

Section: Central Control Of Masticationmentioning

confidence: 99%

“…Additional EMG measurements are needed to analyze the actual masticatory strength. It would not be permissible to draw conclusions about loads on the craniomandibular joints on the basis of muscle activity on EMG [73,74]. The hardness or consistency of food modulates EMG activity, especially during the initial masticatory movements [67].…”

Section: Central Control Of Masticationmentioning

confidence: 99%

Human mastication

Slavicek

2010

J. Stomat. Occ. Med.

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Task-dependence of Jaw Elevator and Depressor Co-activation

Cited by 18 publications

References 19 publications

Biting intentions modulate digastric reflex responses to sudden unloading of the jaw

Biting intentions modulate digastric reflex responses to sudden unloading of the jaw

A novel standard food model to analyze the individual parameters of human mastication

Human mastication

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