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Angst L, Koolstra JH, Wiedemeier D, Van Sluijs RM, Pulfer AM, Gallo LM, Colombo V. Masticatory Muscles Activation and TMJ Space During Asymmetrically Loaded Jaw Closing. Ann Biomed Eng 2024; 52:877-887. [PMID: 38214777 PMCID: PMC10940448 DOI: 10.1007/s10439-023-03424-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Accepted: 12/09/2023] [Indexed: 01/13/2024]
Abstract
Masticatory muscle activation and temporomandibular joint (TMJ) load generated during asymmetrically loaded jaw closing are largely unknown. Two different strategies were developed to explain how the central nervous system (CNS) generates muscle activation patterns during motion: minimization of joint load (MJL) vs. minimization of muscle effort (MME). The aim of the present study was to investigate, experimentally, the neuromuscular strategy selected by the CNS to coordinate jaw closing in reaction to the application of an external asymmetric load. Masticatory muscle activation was measured with electromyography (EMG) and the minimum intra-articular distance (MID) was assessed by dynamic stereometry to infer joint loading. Ten healthy subjects performed jaw-closing movements against an asymmetric mandibular load set from 0.0 to 2.0 kg in 0.5-kg steps. Recordings were analyzed by exploratory and graphical statistical tools. Moreover, the observed differences in MID and EMG among the various mandibular loads were tested using non-parametric tests for repeated measures data. The ipsilateral-contralateral differences in MID and EMG of the anterior temporalis showed a significant increase (p < 0.001, p = 0.01) with increasing asymmetrical load with both joints being most heavily loaded at 1 kg. EMG signals of the masseter did not change significantly with increasing load. This study is the first to have analyzed the changes in the TMJ intra-articular space during asymmetrically loaded jaw-closing movements, not only three dimensionally and dynamically, but also combined with EMG. Asymmetrical load affected the TMJ space and masticatory muscle activation patterns, primarily resulting in an increased activation of the anterior temporalis muscle. This might suggest the involvement of a control mechanism to protect the joints from overloading. However, the results do not fully support the hypothesis of MJL nor the MME strategy.
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Affiliation(s)
- Lea Angst
- Clinic of Masticatory Disorders, Centre of Dental Medicine, University of Zurich, Plattenstrasse 11, 8032, Zurich, Switzerland.
| | - Jan Harm Koolstra
- Department of Functional Anatomy, Academic Centre for Dentistry Amsterdam (ACTA), Research Institute MOVE, University of Amsterdam and VU University, Amsterdam, The Netherlands
| | - Daniel Wiedemeier
- Statistical Services, Center of Dental Medicine, University of Zurich, Zurich, Switzerland
| | - Rachel M Van Sluijs
- Department of Functional Anatomy, Academic Centre for Dentistry Amsterdam (ACTA), Research Institute MOVE, University of Amsterdam and VU University, Amsterdam, The Netherlands
| | - Anina M Pulfer
- Clinic of Masticatory Disorders, Centre of Dental Medicine, University of Zurich, Plattenstrasse 11, 8032, Zurich, Switzerland
| | - Luigi M Gallo
- Clinic of Masticatory Disorders, Centre of Dental Medicine, University of Zurich, Plattenstrasse 11, 8032, Zurich, Switzerland
| | - Vera Colombo
- Clinic of Masticatory Disorders, Centre of Dental Medicine, University of Zurich, Plattenstrasse 11, 8032, Zurich, Switzerland
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Richard BA, Spence M, Rull-Garza M, Roba YT, Schwarz D, Ramsay JB, Laurence-Chasen JD, Ross CF, Konow N. Rhythmic chew cycles with distinct fast and slow phases are ancestral to gnathostomes. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220539. [PMID: 37839454 PMCID: PMC10577039 DOI: 10.1098/rstb.2022.0539] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 06/19/2023] [Indexed: 10/17/2023] Open
Abstract
Intra-oral food processing, including chewing, is important for safe swallowing and efficient nutrient assimilation across tetrapods. Gape cycles in tetrapod chewing consist of four phases (fast open and -close, and slow open and -close), with processing mainly occurring during slow close. Basal aquatic-feeding vertebrates also process food intraorally, but whether their chew cycles are partitioned into distinct phases, and how rhythmic their chewing is, remains unknown. Here, we show that chew cycles from sharks to salamanders are as rhythmic as those of mammals, and consist of at least three, and often four phases, with phase distinction occasionally lacking during jaw opening. In fishes and aquatic-feeding salamanders, fast open has the most variable duration, more closely resembling mammals than basal amniotes (lepidosaurs). Across ontogenetically or behaviourally mediated terrestrialization, salamanders show a distinct pattern of the second closing phase (near-contact) being faster than the first, with no clear pattern in partitioning of variability across phases. Our results suggest that distinct fast and slow chew cycle phases are ancestral for jawed vertebrates, followed by a complicated evolutionary history of cycle phase durations and jaw velocities across fishes, basal tetrapods and mammals. These results raise new questions about the mechanical and sensorimotor underpinnings of vertebrate food processing. This article is part of the theme issue 'Food processing and nutritional assimilation in animals'.
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Affiliation(s)
- Brian A. Richard
- Department of Biological Sciences, University of Massachusetts, Lowell, MA 01954, USA
| | - Meghan Spence
- Department of Biological Sciences, University of Massachusetts, Lowell, MA 01954, USA
| | - Mateo Rull-Garza
- Department of Biological Sciences, University of Massachusetts, Lowell, MA 01954, USA
| | - Yonas Tolosa Roba
- Department of Biological Sciences, University of Massachusetts, Lowell, MA 01954, USA
| | - Daniel Schwarz
- Department of Paleontology, State Museum of Natural History, 70191 Stuttgart, Germany
- Institute of Zoology and Evolutionary Research, Friedrich Schiller University, 07743 Jena, Germany
| | - Jason B. Ramsay
- Biology Department, Westfield State University, Westfield, MA 01086, USA
| | - J. D. Laurence-Chasen
- Department of Organismic Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA
| | - Callum F. Ross
- Department of Organismic Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA
| | - Nicolai Konow
- Department of Biological Sciences, University of Massachusetts, Lowell, MA 01954, USA
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Seki S, Kitaoka Y, Kawata S, Nishiura A, Uchihashi T, Hiraoka SI, Yokota Y, Isomura ET, Kogo M, Tanaka S. Characteristics of Sensory Neuron Dysfunction in Amyotrophic Lateral Sclerosis (ALS): Potential for ALS Therapy. Biomedicines 2023; 11:2967. [PMID: 38001967 PMCID: PMC10669304 DOI: 10.3390/biomedicines11112967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 10/24/2023] [Accepted: 10/29/2023] [Indexed: 11/26/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder characterised by the progressive degeneration of motor neurons, resulting in muscle weakness, paralysis, and, ultimately, death. Presently, no effective treatment for ALS has been established. Although motor neuron dysfunction is a hallmark of ALS, emerging evidence suggests that sensory neurons are also involved in the disease. In clinical research, 30% of patients with ALS had sensory symptoms and abnormal sensory nerve conduction studies in the lower extremities. Peroneal nerve biopsies show histological abnormalities in 90% of the patients. Preclinical research has reported several genetic abnormalities in the sensory neurons of animal models of ALS, as well as in motor neurons. Furthermore, the aggregation of misfolded proteins like TAR DNA-binding protein 43 has been reported in sensory neurons. This review aims to provide a comprehensive description of ALS-related sensory neuron dysfunction, focusing on its clinical changes and underlying mechanisms. Sensory neuron abnormalities in ALS are not limited to somatosensory issues; proprioceptive sensory neurons, such as MesV and DRG neurons, have been reported to form networks with motor neurons and may be involved in motor control. Despite receiving limited attention, sensory neuron abnormalities in ALS hold potential for new therapies targeting proprioceptive sensory neurons.
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Affiliation(s)
- Soju Seki
- Department of Oral and Maxillofacial Surgery, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita 565-0871, Osaka, Japan
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Kitaoka Y, Seki S, Kawata S, Nishiura A, Kawamura K, Hiraoka SI, Kogo M, Tanaka S. Analysis of Feeding Behavior Characteristics in the Cu/Zn Superoxide Dismutase 1 (SOD1) SOD1G93A Mice Model for Amyotrophic Lateral Sclerosis (ALS). Nutrients 2023; 15:nu15071651. [PMID: 37049492 PMCID: PMC10097127 DOI: 10.3390/nu15071651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 03/24/2023] [Accepted: 03/24/2023] [Indexed: 03/31/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive disease affecting upper and lower motor neurons. Feeding disorders are observed in patients with ALS. The mastication movements and their systemic effects in patients with ALS with feeding disorders remain unclear. Currently, there is no effective treatment for ALS. However, it has been suggested that treating feeding disorders and improving nutritional status may prolong the lives of patients with ALS. Therefore, this study elucidates feeding disorders observed in patients with ALS and future therapeutic agents. We conducted a temporal observation of feeding behavior and mastication movements using an open-closed mouth evaluation artificial intelligence (AI) model in an ALS mouse model. Furthermore, to determine the cause of masticatory rhythm modulation, we conducted electrophysiological analyses of mesencephalic trigeminal neurons (MesV). Here, we observed the modulation of masticatory rhythm with a prolonged open phase in the ALS mouse model from the age of 12 weeks. A decreased body weight was observed simultaneously, indicating a correlation between the prolongation of the open phase and the decrease observed. We found that the percentage of firing MesV was markedly decreased. This study partially clarifies the role of feeding disorders in ALS.
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Faltings L, Young MW, Ross CF, Granatosky MC. Got rhythm? Rhythmicity differences reflect different optimality criteria in feeding and locomotor systems. Evolution 2022; 76:2181-2190. [PMID: 35862552 DOI: 10.1111/evo.14569] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 04/19/2022] [Accepted: 05/24/2022] [Indexed: 01/22/2023]
Abstract
Evolutionary analyses of joint kinematics and muscle mechanics suggest that, during cyclic behaviors, tetrapod feeding systems are optimized for precise application of forces over small displacements during chewing, whereas locomotor systems are more optimized for large and rapid joint excursions during walking and running. If this hypothesis is correct, then it stands to reason that other biomechanical variables in the feeding and locomotor systems should also reflect these divergent functions. We compared rhythmicity of cyclic jaw and limb movements in feeding and locomotor systems in 261 tetrapod species in a phylogenetic context. Accounting for potential confounding variables, our analyses reveal higher rhythmicity of cyclic movements of the limbs than of the jaw. Higher rhythmicity in the locomotor system corroborates a hypothesis of stronger optimization for energetic efficiency: deviation from the limbs' natural frequency results in greater variability of center of mass movements and limb inertial changes, and therefore more work by limb muscles. Relatively lower rhythmicity in the feeding system may be a consequence of the necessity to prevent tooth breakage and wear, the greater complexity of coordination with tongue movements, and/or a greater emphasis on energy storage in elastic elements rather than the kinetics of limb movement.
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Affiliation(s)
- Lukas Faltings
- College of Osteopathic Medicine, New York Institute of Technology, Old Westbury, New York, 11568, USA
| | - Melody W Young
- College of Osteopathic Medicine, New York Institute of Technology, Old Westbury, New York, 11568, USA
- Department of Anatomy, Center for Biomedical Innovation, College of Osteopathic Medicine, New York Institute of Technology, Old Westbury, New York, 11568, USA
| | - Callum F Ross
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, Illinois, 60637, USA
| | - Michael C Granatosky
- College of Osteopathic Medicine, New York Institute of Technology, Old Westbury, New York, 11568, USA
- Department of Anatomy, Center for Biomedical Innovation, College of Osteopathic Medicine, New York Institute of Technology, Old Westbury, New York, 11568, USA
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Laurence-Chasen JD, Arce-McShane FI, Hatsopoulos NG, Ross CF. Loss of oral sensation impairs feeding performance and consistency of tongue-jaw coordination. J Oral Rehabil 2022; 49:806-816. [PMID: 35514258 PMCID: PMC9540871 DOI: 10.1111/joor.13336] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 03/07/2022] [Accepted: 04/13/2022] [Indexed: 11/24/2022]
Abstract
Background Individuals with impaired oral sensation report difficulty chewing, but little is known about the underlying changes to tongue and jaw kinematics. Methodological challenges impede the measurement of 3D tongue movement and its relationship to the gape cycle. Objective The aim of this study was to quantify the impact of loss of oral somatosensation on feeding performance, 3D tongue kinematics and tongue‐jaw coordination. Methodology XROMM (X‐ray Reconstruction of Moving Morphology) was used to quantify 3D tongue and jaw kinematics during feeding in three rhesus macaques (Macaca mulatta) before and after an oral tactile nerve block. Feeding performance was measured using feeding sequence duration, number of manipulation cycles and swallow frequency. Coordination was measured using event‐ and correlation‐based metrics of jaw pitch, anterior tongue length, width and roll. Results In the absence of tactile sensation to the tongue and other oral structures, feeding performance decreased, and the fast open phase of the gape cycle became significantly longer, relative to the other phases (p < .05). The tongue made similar shapes in both the control and nerve block conditions, but the pattern of tongue‐jaw coordination became significantly more variable after the block (p < .05). Conclusion Disruption of oral somatosensation impacts feeding performance by introducing variability into the typically tight pattern of tongue‐jaw coordination.
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Affiliation(s)
- J D Laurence-Chasen
- Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, IL, USA
| | | | - Nicholas G Hatsopoulos
- Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, IL, USA
| | - Callum F Ross
- Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, IL, USA
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Kochi I, Takei E, Maeda R, Ito K, Magara J, Tsujimura T, Kulvanich S, Inoue M. Changes of bolus properties and the triggering of swallowing in healthy humans. J Oral Rehabil 2021; 48:592-600. [PMID: 33481324 DOI: 10.1111/joor.13151] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 01/14/2021] [Indexed: 11/26/2022]
Abstract
There is wide variation in chewing behaviours, even among healthy humans. Further, the way in which humans determine swallowing initiation when chewing solid foods remains unclear. The current study sought to investigate how the bolus properties change over time during chewing, and to clarify which factors affect chewing and swallowing behaviours, including swallowing initiation, in healthy humans. Twenty-four healthy volunteers were instructed to chew 8 g of steamed rice and spit it out at 50%, 100% and 150% of their own chewing duration, defined as the time of chewing from onset of the first chewing cycle to onset of the first swallow. Chewing and swallowing behaviours were monitored and determined by visual inspection of video recordings. The physical properties such as hardness, cohesiveness and adhesiveness as well as water content of the bolus were measured. In each subject, maximum bite force, tongue pressure and stimulated salivary flow rate were also measured. Hardness gradually decreased, and the cohesiveness and water content of the bolus did not change up to 50% of chewing duration, followed by a slight but significant increase. The adhesiveness of the bolus rapidly decreased at the beginning of chewing. Chewing duration was significantly related to stimulated salivary flow rate; greater salivary flow rate was associated with shorter chewing duration. Variation of chewing duration and swallowing initiation was not dependent on bolus properties during the chewing of steamed rice, but mainly depended on the surface lubrication of the bolus.
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Affiliation(s)
- Izumi Kochi
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Eri Takei
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Rumiko Maeda
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.,Department of Rehabilitation, Faculty of Health Science, Kansai University of Welfare Sciences, Osaka, Japan
| | - Kayoko Ito
- Oral Rehabilitation, Niigata University Medical and Dental Hospital, Niigata, Japan
| | - Jin Magara
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Takanori Tsujimura
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Sirima Kulvanich
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Makoto Inoue
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
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Hotta H, Suzuki H, Inoue T, Stewart M. Involvement of the basal nucleus of Meynert on regional cerebral cortical vasodilation associated with masticatory muscle activity in rats. J Cereb Blood Flow Metab 2020; 40:2416-2428. [PMID: 31847668 PMCID: PMC7820681 DOI: 10.1177/0271678x19895244] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We examined the neural mechanisms for increases in regional cerebral blood flow (rCBF) in the neocortex associated with mastication, focusing on the cortical vasodilative system derived from the nucleus basalis of Meynert (NBM). In pentobarbital-anesthetized rats, parietal cortical rCBF was recorded simultaneously with electromyogram (EMG) of jaw muscles, local field potentials of frontal cortex, multi-unit activity of NBM neurons, and systemic mean arterial pressure (MAP). When spontaneous rhythmic EMG activity was observed with cortical desynchronization, an increase in NBM activity and a marked rCBF increase independent of MAP changes were observed. A similar rCBF increase was elicited by repetitive electrical stimulation of unilateral cortical masticatory areas. The magnitude of rCBF increase was partially attenuated by administration of the GABAergic agonist muscimol into the NBM. The rCBF increase persisted after immobilization with systemic muscle relaxant (vecuronium). rCBF did not change when jaw muscle activity was induced by electrical stimulation of the pyramidal tract. The results suggest that activation of NBM vasodilator neurons contributes at least in part to the rCBF increase associated with masticatory muscle activity, and that the NBM activation is induced by central commands from the motor cortex, independently of feedback from brainstem central pattern generator or contracting muscles.
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Affiliation(s)
- Harumi Hotta
- Department of Autonomic Neuroscience, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Harue Suzuki
- Department of Autonomic Neuroscience, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Tomio Inoue
- Department of Oral Physiology, School of Dentistry, Showa University, Tokyo, Japan
| | - Mark Stewart
- Department of Physiology & Pharmacology, State University of New York Downstate Medical Center, New York, NY, USA.,Department of Neurology, State University of New York Downstate Medical Center, New York, NY, USA
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Grigoriadis A, Kumar A, Åberg MK, Trulsson M. Effect of Sudden Deprivation of Sensory Inputs From Periodontium on Mastication. Front Neurosci 2019; 13:1316. [PMID: 31920486 PMCID: PMC6914695 DOI: 10.3389/fnins.2019.01316] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 11/25/2019] [Indexed: 01/05/2023] Open
Abstract
Objective To investigate the effect of sudden deprivation of sensory inputs from the periodontium on jaw kinematics and time-varying activation profile of the masseter muscle. Methods Fourteen (age range: 22–26 years; four men) healthy and natural dentate volunteers participated in a single experimental session. During the experiment, the participants were asked to eat six hard visco-elastic test food models, three each before and after an anesthetic intervention. The movements of the jaw in three dimensions and electromyographic (EMG) activity of the masseter muscle on the chewing side were recorded. Results The results of the study showed no significant differences in the number of chewing cycles (P = 0.233) and the duration of chewing sequence (P = 0.198) due to sudden deprivation of sensory inputs from the periodontium. However, there was a significant increase in the jaw opening velocity (P = 0.030) and a significant increase in the duration of occlusal phase (P = 0.004) during the anesthetized condition. The EMG activity of the jaw closing phase was significantly higher during the control condition [116.5 arbitrary units (AU)] than anesthetized condition (93.9 AU). The temporal profile of the masseter muscle showed a biphasic increase in the excitatory muscle drive in the control condition but this increase was virtually absent during the anesthetized condition. Conclusion Sudden deprivation of sensory inputs from the periodontium affects the jaw kinematics and jaw muscle activity, with a clear difference in the time-varying activation profile of the masseter muscle. The activation profile of the masseter muscle shows that periodontal mechanoreceptors contribute to approximately 20% of the EMG activity during the jaw closing phase.
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Affiliation(s)
- Anastasios Grigoriadis
- Section of Oral Rehabilitation, Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden.,Scandinavian Center for Orofacial Neurosciences, Huddinge, Sweden
| | - Abhishek Kumar
- Section of Oral Rehabilitation, Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden.,Scandinavian Center for Orofacial Neurosciences, Huddinge, Sweden
| | - Magnus K Åberg
- Department of Environmental Science and Analytical Chemistry, Stockholm University, Stockholm, Sweden
| | - Mats Trulsson
- Section of Oral Rehabilitation, Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden.,Scandinavian Center for Orofacial Neurosciences, Huddinge, Sweden
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Yamada K, Higashiyama M, Toyoda H, Masuda Y, Kogo M, Yoshida A, Kato T. Experimentally induced rhythmic jaw muscle activities during non‐rapid eye movement sleep in freely moving guinea pigs. J Sleep Res 2019; 28:e12823. [DOI: 10.1111/jsr.12823] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 12/15/2018] [Indexed: 11/28/2022]
Affiliation(s)
- Ken‐ichi Yamada
- Department of Oral and Maxillofacial Surgery I Osaka University Graduate School of Dentistry Osaka Japan
| | - Makoto Higashiyama
- Department of Oral Physiology Osaka University Graduate School of Dentistry Osaka Japan
| | - Hiroki Toyoda
- Department of Oral Physiology Osaka University Graduate School of Dentistry Osaka Japan
| | - Yuji Masuda
- Department of Oral and Maxillofacial NeurobiologyGraduate School of Oral MedicineMatsumoto Dental University Shiojiri Japan
| | - Mikihiko Kogo
- Department of Oral and Maxillofacial Surgery I Osaka University Graduate School of Dentistry Osaka Japan
| | - Atsushi Yoshida
- Department of Oral Anatomy and Neurobiology Osaka University Graduate School of Dentistry Osaka Japan
| | - Takafumi Kato
- Department of Oral Physiology Osaka University Graduate School of Dentistry Osaka Japan
- Sleep Medicine Center Osaka University Hospital Osaka Japan
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Grigoriadis A, Trulsson M. Excitatory drive of masseter muscle during mastication with dental implants. Sci Rep 2018; 8:8597. [PMID: 29872098 PMCID: PMC5988651 DOI: 10.1038/s41598-018-26926-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 05/17/2018] [Indexed: 11/23/2022] Open
Abstract
Previously we have reported a biphasic increase in excitatory drive of the masseter muscle during natural chewing in young adults. We now hypothesize that sensory inputs from the periodontal mechanoreceptors (PMRs) are responsible for the late increase in excitatory drive during this biphasic movement. 13 participants with implant-supported bridges in both jaws, and thus lacking PMRs, and 13 participants with natural dentition chewed and swallowed model food of different hardness. Electromyographic (EMG) activity of the masseter muscle was recorded, along with the position of the mandible, and the muscle activity and jaw kinematics during the different phases of the chewing cycle were analyzed. Throughout the entire masticatory sequence, the excitatory drive of the masseter muscle during the jaw closing increased in a biphasic manner for the dentate participants; whereas biphasic elevation was observed only during the middle and last segments in the implant participants. Dentate participants exhibited significantly greater boosting of the EMG activity during late jaw closing than the implant participants, irrespective of food hardness and segment of the masticatory sequence. Sensory information from PMRs are required for boosting the enhancement of masseter muscle activity during the late jaw closing, during tooth-food contact.
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Affiliation(s)
- Anastasios Grigoriadis
- Section of Oral Rehabilitation, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden.
| | - Mats Trulsson
- Section of Oral Rehabilitation, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden
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12
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Ross CF, Porro LB, Herrel A, Evans SE, Fagan MJ. Bite force and cranial bone strain in four species of lizards. J Exp Biol 2018; 221:jeb.180240. [DOI: 10.1242/jeb.180240] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 10/16/2018] [Indexed: 11/20/2022]
Abstract
In vivo bone strain data provide direct evidence of strain patterns in the cranium during biting. Compared to mammals, in vivo bone strains in lizard skulls are poorly documented. This paper presents strain data from the skulls of Anolis equestris, Gekko gecko, Iguana iguana and Salvator merianae during transducer biting. Analysis of variance was used to investigate effects of bite force, bite point, diet, cranial morphology and cranial kinesis on strain magnitudes. Within individuals the most consistent determinants of variance in bone strain magnitudes are gage location and bite point, with the importance of bite force varying between individuals. Inter-site variance in strain magnitudes—strain gradient—is present in all individuals, and varies with bite point. Between individuals within species, variance in strain magnitude is driven primarily by variation in bite force, not gage location or bite point, suggesting that inter-individual variation in patterns of strain magnitude is minimal. Between species, variation in strain magnitudes is significantly impacted by bite force and species membership, as well as by interactions between gage location, species, and bite point. Independent of bite force, species differences in cranial strain magnitudes may reflect selection for different cranial morphology in relation to feeding function, but what these performance criteria are is not clear. The relatively low strain magnitudes in Iguana and Uromastyx compared to other lizards may be related to their herbivorous diet. Cranial kinesis and the presence or absence of postorbital and supratemporal bars are not important determinants of inter-specific variation in strain magnitudes.
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Affiliation(s)
- Callum F. Ross
- Organismal Biology & Anatomy, University of Chicago, 1027 East 57th Street, Chicago, IL 60637, USA
| | - Laura B. Porro
- School of Earth Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
| | - Anthony Herrel
- Sorbonne Universités, Département Adaptations du Vivant, UMR 7179, C.N.R.S/M.N.H.N., Paris, France
| | - Susan E. Evans
- Department of Cell and Developmental Biology, UCL, University College London, London, WC1E 6BT, UK
| | - Michael J. Fagan
- School of Engineering and Computer Science, University of Hull, Hull, HU6 7RX, UK
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Fischer MJ, Stephan M, Kielstein H, Rahne H, Nugraha B, Gutenbrunner C, Ro JY, Svensson P. Functions of the temporomandibular system in extracranial chronic pain conditions: modulatory effects on nocifensive behavior in an animal model. J Manipulative Physiol Ther 2014; 37:485-93. [PMID: 25150425 DOI: 10.1016/j.jmpt.2014.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Revised: 01/22/2014] [Accepted: 01/23/2014] [Indexed: 10/24/2022]
Abstract
OBJECTIVE Mastication may be able to activate endogenous pain inhibitory mechanisms and therefore lead to modulation of nociceptive processing. The purpose of this study was to examine the possible effect of food consistency on noxious input from the spinal system. METHODS Three groups of adult male Sprague-Dawley rats were given an injection of complete Freund adjuvant in a hind paw 10 days after eating soft or hard food (one group received a saline injection-the control group [C]; the other group (D) received no injection). Nocifensive behavior was assessed with the use of the hot plate and tail flick assays at 1, 3, 6, and 12 hours and at 6.5 days after injection for groups A/B, and c-Fos activity was assessed in the brain after testing. Groups C/D had hot plate testing at 1 hour and 6.5 days. The data were analyzed by general linear modeling and 1-way analysis of variance. RESULTS There was a small increase in the hot plate percent maximum possible effect (MPE) from -45.7 to -61.1 in group A over the length of the experiment, but a very small decrease for group B over the same period (-33.5 to -28.8). For the saline control group, there was a small increase toward 0 %MPE over the same time frame (-15.0 to 1.7). The %MPE differences were significant between groups A and C (P < .0005), but not significant between the other groups (F = 13.34, df = 2, P = .001, observed power = 99%). Using the pooled results (all time points), the differences between all groups were significant (P < .0005). There were no significant differences in the tail flick test. c-Fos was mainly observed in the raphe pallidus area with significant differences between groups A and B at 3 and 6 hours after injection of CFA (P = .027 and .022, respectively). CONCLUSIONS The results of this study indicate that food consistency (hardness) influences nocifensive behavior in this animal model via a descending pathway operating at the supraspinal level.
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Affiliation(s)
- Michael J Fischer
- Lecturer/Privatdozent, Department of Rehabilitation Medicine, Hanover Medical School, 30625 Hanover, Germany; Lecturer/Privatdozent, Department of Orthopaedics, Hanover Medical School, Medical University Innsbruck, A-6020 Innsbruck, Austria
| | - Michael Stephan
- Department of Psychosomatics and Psychotherapy, Hanover Medical School, 30625 Hanover, Germany
| | - Heike Kielstein
- Professor, Department of Anatomy and Cell Biology, Faculty of Medicine, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Henning Rahne
- Department of Rehabilitation Medicine, Hanover Medical School, 30625 Hanover, Germany
| | - Boya Nugraha
- Department of Rehabilitation Medicine, Hanover Medical School, 30625 Hanover, Germany
| | - Christoph Gutenbrunner
- Professor, Department of Rehabilitation Medicine, Hanover Medical School, 30625 Hanover, Germany
| | - Jin Y Ro
- Professor, Department of Biomedical Sciences, Program in Neuroscience, School of Dentistry, University of Maryland, Baltimore, MD
| | - Peter Svensson
- Professor, Department of Clinical Oral Physiology, School of Dentistry, University of Aarhus, Aarhus, Denmark; Department of Oral and Maxillofacial Surgery, Aarhus University Hospital, Aarhus, Denmark
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Grigoriadis A, Johansson RS, Trulsson M. Temporal profile and amplitude of human masseter muscle activity is adapted to food properties during individual chewing cycles. J Oral Rehabil 2014; 41:367-73. [DOI: 10.1111/joor.12155] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/06/2014] [Indexed: 11/29/2022]
Affiliation(s)
- A. Grigoriadis
- Department of Dental Medicine; Karolinska Institutet; Huddinge Sweden
| | - R. S. Johansson
- Department of Integrative Medical Biology; Umeå University; Umeå Sweden
| | - M. Trulsson
- Department of Dental Medicine; Karolinska Institutet; Huddinge Sweden
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15
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Yamada A, Kajii Y, Sakai S, Tsujimura T, Nakamura Y, Ariyasinghe S, Magara J, Inoue M. Effects of chewing and swallowing behavior on jaw opening reflex responses in freely feeding rabbits. Neurosci Lett 2013; 535:73-7. [PMID: 23313598 DOI: 10.1016/j.neulet.2012.12.047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2012] [Revised: 12/26/2012] [Accepted: 12/27/2012] [Indexed: 10/27/2022]
Abstract
It has been reported that the jaw opening reflex (JOR) evoked by intra-oral innocuous stimulation was suppressed during a reflex swallow in anesthetized animals only. However, the mechanism of JOR inhibition during swallowing has not yet been elucidated. The aim of the present study was to investigate the effects of peripheral nerve stimulation on masticatory behaviors, as well as the modulation of low threshold afferent evoked JOR responses during chewing and swallowing in freely feeding animals. The JOR in the digastric muscle was evoked by low threshold electrical stimulation of the inferior alveolar nerve (IAN). Changes in the peak-to-peak amplitude of digastric electromyographic responses were compared among the phases of chewing and swallowing. IAN stimulation did not produce any differences in cycle duration, gape of the jaw in one cycle, or swallowing interval, suggesting a minimal effect on feeding behaviors. The JOR amplitude during the fast-closing, slow-closing, and slow-opening phases of chewing was significantly smaller than that of the control (recorded when the animal was at rest) and fast-opening phase. During swallowing, the JOR amplitude was significantly less than the control. Inhibition of the JOR during swallowing is assumed to prevent unnecessary opposing jaw opening motion.
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Affiliation(s)
- Aki Yamada
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
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New directions for understanding neural control in swallowing: the potential and promise of motor learning. Dysphagia 2012. [PMID: 23192633 DOI: 10.1007/s00455-012-9432-y] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Oropharyngeal swallowing is a complex sensorimotor phenomenon that has had decades of research dedicated to understanding it more thoroughly. However, the underlying neural mechanisms responsible for normal and disordered swallowing remain very vague. We consider this gap in knowledge the result of swallowing research that has been broad (identifying phenomena) but not deep (identifying what controls the phenomena). The goals of this review are to address the complexity of motor control of oropharyngeal swallowing and to review the principles of motor learning based on limb movements as a model system. We compare this literature on limb motor learning to what is known about oropharyngeal function as a first step toward suggesting the use of motor learning principles in swallowing research.
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Isogai F, Kato T, Fujimoto M, Toi S, Oka A, Adachi T, Maeda Y, Morimoto T, Yoshida A, Masuda Y. Cortical area inducing chewing-like rhythmical jaw movements and its connections with thalamic nuclei in guinea pigs. Neurosci Res 2012; 74:239-47. [PMID: 23142519 DOI: 10.1016/j.neures.2012.10.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2012] [Revised: 10/17/2012] [Accepted: 10/30/2012] [Indexed: 11/30/2022]
Abstract
Repetitive electrical stimulation to the cortical masticatory areas (CMA) evokes rhythmical jaw movements (RJM), whose patterns vary depending on the stimulation site, in various species. In guinea pigs, although alternating bilateral jaw movements are usually seen during natural chewing, it is still unclear which cortical areas are responsible for chewing-like RJM. To address this issue, we first defined the cortical areas inducing chewing-like RJM by intracortical microstimulation. Stimulation of the most lateral area of the CMA, the granular cortex, induced chewing-like RJM, but from the region medial to this area, simple vertical RJM were induced. Subsequently, to reveal the properties of these two areas in the CMA, the connections between the CMA and the dorsal thalamus were examined by neuronal tract-tracing techniques. The area inducing chewing-like RJM possessed strong reciprocal connections, mainly with the medial part of the ventral posteromedial nucleus, which is the sensory-relay thalamus. On the other hand, the simple vertical RJM-inducing area had reciprocal connections with the motor thalamus. The present study suggests that the CMA inducing chewing-like RJM is different from the CMA inducing simple vertical RJM, and plays a role in cortically induced chewing-like RJM under the influence of the sensory thalamus in guinea pigs.
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Affiliation(s)
- Fumihiko Isogai
- Division of Oral Maxillofacial Biology, Institute for Oral Science, Matsumoto Dental University, 1780 Gobara, Hirooka, Shiojiri, Nagano 399-0781, Japan
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Tsukiboshi T, Sato H, Tanaka Y, Saito M, Toyoda H, Morimoto T, Türker KS, Maeda Y, Kang Y. Illusion caused by vibration of muscle spindles reveals an involvement of muscle spindle inputs in regulating isometric contraction of masseter muscles. J Neurophysiol 2012; 108:2524-33. [PMID: 22914653 DOI: 10.1152/jn.00997.2011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Spindle Ia afferents may be differentially involved in voluntary isometric contraction, depending on the pattern of synaptic connections in spindle reflex pathways. We investigated how isometric contraction of masseter muscles is regulated through the activity of their muscle spindles that contain the largest number of intrafusal fibers among skeletal muscle spindles by examining the effects of vibration of muscle spindles on the voluntary isometric contraction. Subjects were instructed to hold the jaw at resting position by counteracting ramp loads applied on lower molar teeth. In response to the increasing-ramp load, the root mean square (RMS) of masseter EMG activity almost linearly increased under no vibration, while displaying a steep linear increase followed by a slower increase under vibration. The regression line of the relationship between the load and RMS was significantly steeper under vibration than under no vibration, suggesting that the subjects overestimated the ramp load and excessively counteracted it as reflected in the emergence of bite pressure. In response to the decreasing-ramp load applied following the increasing one, the RMS hardly decreased under vibration unlike under no vibration, leading to a generation of bite pressure even after the offset of the negative-ramp load until the vibration was ceased. Thus the subjects overestimated the increasing rate of the load while underestimating the decreasing rate of the load, due to the vibration-induced illusion of jaw opening. These observations suggest that spindle Ia/II inputs play crucial roles both in estimating the load and in controlling the isometric contraction of masseter muscles in the jaw-closed position.
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Affiliation(s)
- Taisuke Tsukiboshi
- Department of Neuroscience and Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan
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Tassinari CA, Gardella E, Cantalupo G, Rubboli G. Relationship of Central Pattern Generators with Parasomnias and Sleep-Related Epileptic Seizures. Sleep Med Clin 2012. [DOI: 10.1016/j.jsmc.2012.01.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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20
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Panagiotopoulou O, Kupczik K, Cobb SN. The mechanical function of the periodontal ligament in the macaque mandible: a validation and sensitivity study using finite element analysis. J Anat 2011; 218:75-86. [PMID: 20584094 DOI: 10.1111/j.1469-7580.2010.01257.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Whilst the periodontal ligament (PDL) acts as an attachment tissue between bone and tooth, hypotheses regarding the role of the PDL as a hydrodynamic damping mechanism during intraoral food processing have highlighted its potential importance in finite element (FE) analysis. Although experimental and constitutive models have correlated the mechanical function of the PDL tissue with its anisotropic, heterogeneous, viscoelastic and non-linear elastic nature, in many FE simulations the PDL is either present or absent, and when present is variably modelled. In addition, the small space the PDL occupies and the inability to visualize the PDL tissue using μCT scans poses issues during FE model construction and so protocols for the PDL thickness also vary. In this paper we initially test and validate the sensitivity of an FE model of a macaque mandible to variations in the Young's modulus and the thickness of the PDL tissue. We then tested the validity of the FE models by carrying out experimental strain measurements on the same mandible in the laboratory using laser speckle interferometry. These strain measurements matched the FE predictions very closely, providing confidence that material properties and PDL thickness were suitably defined. The FE strain results across the mandible are generally insensitive to the absence and variably modelled PDL tissue. Differences are only found in the alveolar region adjacent to the socket of the loaded tooth. The results indicate that the effect of the PDL on strain distribution and/or absorption is restricted locally to the alveolar bone surrounding the teeth and does not affect other regions of the mandible.
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Affiliation(s)
- Olga Panagiotopoulou
- Functional Morphology and Evolution Unit, Hull York Medical School, University of York, UK.
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21
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Grigoriadis A, Johansson RS, Trulsson M. Adaptability of mastication in people with implant-supported bridges. J Clin Periodontol 2011; 38:395-404. [DOI: 10.1111/j.1600-051x.2010.01697.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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22
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Westberg KG, Kolta A. The trigeminal circuits responsible for chewing. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2011; 97:77-98. [PMID: 21708308 DOI: 10.1016/b978-0-12-385198-7.00004-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Mastication is a vital function that ensures that ingested food is broken down into pieces and prepared for digestion. This review outlines the masticatory behavior in terms of the muscle activation patterns and jaw movements and gives an overview of the organization and function of the trigeminal neuronal circuits that are known to take part in the generation and control of oro-facial motor functions. The basic pattern of rhythmic jaw movements produced during mastication is generated by a Central Pattern Generator (CPG) located in the pons and medulla. Neurons within the CPG have intrinsic properties that produce a rhythmic activity, but the output of these neurons is modified by inputs that descend from the higher centers of the brain, and by feedback from sensory receptors, in order to constantly adapt the movement to the food properties.
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Affiliation(s)
- Karl-Gunnar Westberg
- Department of Integrative Medical Biology, Section for Physiology, Umeå University, SE-90187 Umeå, Sweden
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Abstract
The main text of this chapter, written by James P. Lund, summarizes most of the work related to the neural control of mastication that he conducted with his collaborators throughout the years. From his early PhD work showing that mastication is centrally patterned to his latest work related to the interaction between pain and movement, Lund will have addressed many essential questions regarding the organization and functioning of the masticatory central pattern generator (CPG). His earliest studies examined how the CPG modulates reflexes and the excitability of primary afferents, interneurons, and motoneurons forming their circuitry. He then tackled the question of how the CPG itself was modulated by different types of sensory and cortical inputs. Another series of studies focused on the organization of the subpopulations of neurons forming the CPG, their intrinsic and network properties. Shortly before his untimely passing, he had turned his attention to the potential contribution of muscle spindle afferents to the patterning of mastication as well as to the development of chronic muscle pain.
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Affiliation(s)
- James P Lund
- Faculty of Dentistry, McGill University, Montreal, Quebec, Canada
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24
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Ignatova JP, Kromin AA. Effects of Electrical Stimulation of the Hunger Center in the Lateral Hypothalamus and Food Reinforcement on Impulse Activity of the Proper Masticatory Muscle in Rabbits under Conditions of Hunger and Satiation. Bull Exp Biol Med 2010; 149:671-6. [DOI: 10.1007/s10517-010-1021-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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YASHIRO K, FUKUDA T, TAKADA K. Masticatory jaw movement optimization after introduction of occlusal interference. J Oral Rehabil 2010; 37:163-70. [DOI: 10.1111/j.1365-2842.2009.02034.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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26
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Ross CF, Baden AL, Georgi J, Herrel A, Metzger KA, Reed DA, Schaerlaeken V, Wolff MS. Chewing variation in lepidosaurs and primates. J Exp Biol 2010; 213:572-84. [DOI: 10.1242/jeb.036822] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Mammals chew more rhythmically than lepidosaurs. The research presented here evaluated possible reasons for this difference in relation to differences between lepidosaurs and mammals in sensorimotor systems. Variance in the absolute and relative durations of the phases of the gape cycle was calculated from kinematic data from four species of primates and eight species of lepidosaurs. The primates exhibit less variance in the duration of the gape cycle than in the durations of the four phases making up the gape cycle. This suggests that increases in the durations of some gape cycle phases are accompanied by decreases in others. Similar effects are much less pronounced in the lepidosaurs. In addition, the primates show isometric changes in gape cycle phase durations, i.e. the relative durations of the phases of the gape cycle change little with increasing cycle time. In contrast, in the lepidosaurs variance in total gape cycle duration is associated with increases in the proportion of the cycle made up by the slow open phase. We hypothesize that in mammals the central nervous system includes a representation of the optimal chew cycle duration maintained using afferent feedback about the ongoing state of the chew cycle. The differences between lepidosaurs and primates do not lie in the nature of the sensory information collected and its feedback to the feeding system, but rather the processing of that information by the CNS and its use feed-forward for modulating jaw movements and gape cycle phase durations during chewing.
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Affiliation(s)
- C. F. Ross
- Organismal Biology and Anatomy, University of Chicago, 1027 E. 57th Street, Chicago, IL 60637, USA
| | - A. L. Baden
- Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University, Stony Brook, NY 11794, USA
| | - J. Georgi
- Department of Anatomy, Arizona College of Osteopathic Medicine, Midwestern University, 19555 North 59th Avenue, Glendale, AZ 85308, USA
| | - A. Herrel
- Département d'Ecologie et de Gestion de la Biodiversité, Muséum National d'Histoire Naturelle, 57 rue Cuvier, Case postale 55, 75231, Paris, France
| | - K. A. Metzger
- Hofstra University School of Medicine in Partnership with North Shore-LIJ, 145 Hofstra University, East Library Wing, Hempstead, NY 11549-1010, USA
| | - D. A. Reed
- Organismal Biology and Anatomy, University of Chicago, 1027 E. 57th Street, Chicago, IL 60637, USA
| | - V. Schaerlaeken
- Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610 Antwerpen, Belgium
| | - M. S. Wolff
- Cariology and Comprehensive Care, College of Dentistry, New York University, 345 E 24th Street, New York, NY 10010, USA
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Kanayama H, Masuda Y, Adachi T, Arai Y, Kato T, Morimoto T. Temporal alteration of chewing jaw movements after a reversible bite-raising in guinea pigs. Arch Oral Biol 2010; 55:89-94. [DOI: 10.1016/j.archoralbio.2009.11.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Revised: 11/04/2009] [Accepted: 11/07/2009] [Indexed: 10/20/2022]
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Kolta A, Morquette P, Lavoie R, Arsenault I, Verdier D. Modulation of rhythmogenic properties of trigeminal neurons contributing to the masticatory CPG. BREATHE, WALK AND CHEW: THE NEURAL CHALLENGE: PART I 2010; 187:137-48. [DOI: 10.1016/b978-0-444-53613-6.00009-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Tome W, Yashiro K, Takada K. Orthodontic Treatment of Malocclusion Improves Impaired Skillfulness of Masticatory Jaw Movements. Angle Orthod 2009; 79:1078-83. [DOI: 10.2319/052708-282r.1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Abstract
Objective: To investigate whether individuals with malocclusion show less skillfulness, as represented by kinematic parameters that characterize masticatory jaw movement, compared with those having normal occlusion and, if so, to examine whether more skilled movements are achieved after completion of orthodontic treatment.
Materials and Methods: Lower incisor point movement in space during gum chewing was recorded, and the kinematic traits of such movement were compared among four subject groups: a Control Group (36 females with good occlusion), a Malocclusion Group (24 females with dental malocclusions), an Extraction Group (31 females who had received orthodontic treatment with premolar extraction) and a Nonextraction Group (27 females who had been treated orthodontically without tooth extraction). Before treatment, all subjects in the three experimental groups exhibited dental malocclusions and skeletal class I jaw-base relationship.
Results: Compared with the Malocclusion Group, the lower normalized jerk-cost, the shorter phase durations, the more symmetric property of the velocity profile, and the smaller variance of lateral jaw-closing trajectories near the tooth intercuspation position were determined in the Extraction Group and the Nonextraction Group as well as in the Control Group.
Conclusions: As measured by kinematic parameters such as normalized jerk-costs, velocity profile, and variance of movement trajectories near the endpoint of movement, dental malocclusions were associated with significantly lower skillfulness of masticatory jaw motion, whereas good occlusion and orthodontically improved occlusion (either with or without premolar extraction) were both associated with more skillful motion.
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Affiliation(s)
- Wakako Tome
- a Assistant Professor, Department of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Osaka University, Osaka, Japan
| | - Kohtaro Yashiro
- b Associate Professor, Department of Orthodontics and Dentofacial Orthopedics and Center for Advanced Medical Engineering and Informatics, Osaka University, Osaka, Japan
| | - Kenji Takada
- c Professor and Department Chair, Department of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry and Center for Advanced Medical Engineering and Informatics, Osaka University, Osaka, Japan
- Corresponding author: Kenji Takada, DDS, PhD, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Japan
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Scaling of chew cycle duration in primates. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2009; 138:30-44. [DOI: 10.1002/ajpa.20895] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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PRÖSCHEL PA, JAMAL T, MORNEBURG TR. Motor control of jaw muscles in chewing and in isometric biting with graded narrowing of jaw gape. J Oral Rehabil 2008; 35:722-8. [DOI: 10.1111/j.1365-2842.2008.01871.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Wintergerst AM, Throckmorton GS, Buschang PH. Effects of bolus size and hardness on within-subject variability of chewing cycle kinematics. Arch Oral Biol 2008; 53:369-75. [DOI: 10.1016/j.archoralbio.2007.10.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2007] [Revised: 10/19/2007] [Accepted: 10/25/2007] [Indexed: 11/28/2022]
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SHIMADA A, TANAKA M, YAMASHITA R, NOGUCHI K, TORISU T, YAMABE Y, FUJII H, MURATA H. Automatic regulation of occlusal force because of hardness-change of the bite object. J Oral Rehabil 2007; 35:12-9. [DOI: 10.1111/j.1365-2842.2007.01746.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Passatore M, Roatta S. Modulation operated by the sympathetic nervous system on jaw reflexes and masticatory movement. Arch Oral Biol 2007; 52:343-6. [PMID: 17223067 DOI: 10.1016/j.archoralbio.2006.11.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2006] [Revised: 11/22/2006] [Accepted: 11/22/2006] [Indexed: 11/17/2022]
Abstract
The sympathetic nervous system (SNS), that is activated under condition of physical, psychological and psychosocial stress, affects force production and fatigability of muscles by controlling both muscle blood flow and the intracellular contractile mechanism. In addition SNS may affect motor function by modulating afferent activity from muscle spindles that are highly concentrated in jaw-closing muscles. Possible implications of these actions on masticatory function and myofascial pain are discussed.
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Affiliation(s)
- Magda Passatore
- Department of Neuroscience-Physiology Div, University of Torino Medical School, Torino, Italy.
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Johansson AS, Svensson KG, Trulsson M. Impaired Masticatory Behavior in Subjects With Reduced Periodontal Tissue Support. J Periodontol 2006; 77:1491-7. [PMID: 16945024 DOI: 10.1902/jop.2006.050355] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Mechanoreceptors situated in the periodontal ligament provide detailed information about intensive and spatial aspects of tooth loads, which support the neural control of masticatory forces. We asked whether a reduced periodontal ligament due to periodontitis, and, thus, an altered mechanoreceptive innervation of the teeth, would affect masticatory behavior when subjects used incisors to hold and split food. METHODS We tested 11 subjects with reduced periodontal tissue support that rendered 30% to 70% alveolar bone loss for at least one pair of opposing anterior incisors. Forces were recorded when subjects used their affected incisors to hold half of a peanut for approximately 4 seconds and then split it. Age- and gender-matched healthy subjects served as the control group. None of the participants showed acute oral symptoms or massive periodontal inflammation. RESULTS The test group used greater force when holding food between the teeth (1.1+/-0.4 N [ mean+/-1 SD]) compared to the control group (0.4+/-0.2 N). Hold forces used by subjects in the test group were also more variable, both within and between trials. The increase in bite force applied to split the peanut was slower and more hesitant for subjects in the test group compared to the control group. CONCLUSIONS Reduced periodontal tissue support accompanies impaired regulation of masticatory forces. Faulty mechanoreceptive innervation of the periodontal ligament explains the elevated hold force, whereas a change in biting strategy due to the weakened support of the teeth may account for the more defensive food-splitting behavior.
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Abstract
Natural teeth are equipped with periodontal mechanoreceptors that signal information about tooth loads. In the present review, the basic force-encoding properties of human periodontal receptors will be presented along with a discussion about their likely functional role in the control of human mastication. Microneurographic recordings from single nerve fibres reveal that human periodontal receptors adapt slowly to maintained tooth loads. Most receptors are broadly tuned to the direction of force application, and about half respond to forces applied to more than one tooth. Populations of periodontal receptors, nevertheless, reliably encode information about both the teeth stimulated, and the direction of forces applied to the individual teeth. Information about the magnitude of tooth loads is made available in the mean firing rate response of periodontal receptors. Most receptors exhibit a markedly curved relationship between discharge rate and force amplitude, featuring the highest sensitivity to changes in tooth load at very low force levels (below 1 N for anterior teeth and 4 N for posterior teeth). Thus, periodontal receptors efficiently encode tooth load when subjects contact and gently manipulate food using the teeth. It is demonstrated that signals from periodontal receptors are used in the fine motor control of the jaw and it is clear from studies of various patient groups (e.g. patients with dental implants) that important sensory-motor functions are lost or impaired when these receptors are removed during the extraction of teeth.
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Affiliation(s)
- M Trulsson
- Institute of Odontology, Karolinska Institutet, Huddinge, Sweden.
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38
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Johnsen SE, Trulsson M. Encoding of Amplitude and Rate of Tooth Loads by Human Periodontal Afferents From Premolar and Molar Teeth. J Neurophysiol 2005; 93:1889-97. [PMID: 15563554 DOI: 10.1152/jn.00664.2004] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Microneurographic recordings were obtained from 20 periodontal mechanoreceptive afferents in the inferior alveolar nerve while force profiles of different amplitudes and rates were applied to a premolar or the first molar in the most sensitive direction. The majority of afferents (17/20) showed a hyperbolic relationship between the steady-state discharge rate and the amplitude of the stimulating force, featuring a pronounced saturation tendency. These afferents were also characterized by a similar decline in dynamic sensitivity with increasing amplitude of background force. However, a few afferents (3/20) showed nearly linear stimulus-response relationships and a small decline in dynamic sensitivity with increasing tooth load. Quantitative models developed for all afferents successfully predicted the afferent discharge rates for novel force stimulations. Application of the transfer function to chewing forces predicted that the discharge rates of periodontal afferents rapidly increased at initial tooth contact and continued to discharge as long as the tooth was loaded. However, due to the marked saturation tendencies at higher forces, most periodontal afferents poorly encoded the magnitude of the strong chewing forces. In addition, the discharge rates of a minority of afferents continued to reflect the force profile during high chewing forces. The results revealed that periodontal afferents of posterior teeth were less sensitive at low tooth loads compared with afferents of anterior teeth. During each chewing cycle, periodontal afferents may provide information about the mechanical properties of food shortly after tooth contact that can be used to scale the muscle commands of the upcoming power phase.
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Affiliation(s)
- Skjalg E Johnsen
- Institute of Odontology, Karolinska Institutet, Box 4064, S-141 04 Huddinge, Sweden
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39
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Roatta S, Windhorst U, Djupsjöbacka M, Lytvynenko S, Passatore M. Effects of sympathetic stimulation on the rhythmical jaw movements produced by electrical stimulation of the cortical masticatory areas of rabbits. Exp Brain Res 2004; 162:14-22. [PMID: 15551082 DOI: 10.1007/s00221-004-2102-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2004] [Accepted: 08/18/2004] [Indexed: 10/26/2022]
Abstract
The somatomotor and sympathetic nervous systems are intimately linked. One example is the influence of peripheral sympathetic fibers on the discharge characteristics of muscle spindles. Since muscle spindles play important roles in various motor behaviors, including rhythmic movements, the working hypothesis of this research was that changes in sympathetic outflow to muscle spindles can change rhythmic movement patterns. We tested this hypothesis in the masticatory system of rabbits. Rhythmic jaw movements and EMG activity induced by long-lasting electrical cortical stimulation were powerfully modulated by electrical stimulation of the peripheral stump of the cervical sympathetic nerve (CSN). This modulation manifested itself as a consistent and marked reduction in the excursion of the mandibular movements (often preceded by a transient modest enhancement), which could be attributed mainly to corresponding changes in masseter muscle activity. These changes outlasted the duration of CSN stimulation. In some of the cortically evoked rhythmic jaw movements (CRJMs) changes in masticatory frequency were also observed. When the jaw-closing muscles were subjected to repetitive ramp-and-hold force pulses, the CRMJs changed characteristics. Masseter EMG activity was strongly enhanced and digastric EMG slightly decreased. This change was considerably depressed during CSN stimulation. These effects of CSN stimulation are similar in sign and time course to the depression exerted by sympathetic activity on the jaw-closing muscle spindle discharge. It is suggested that the change in proprioceptive information induced by an increase in sympathetic outflow (a) has important implications even under normal conditions for the control of motor function in states of high sympathetic activity, and (b) is one of the mechanisms responsible for motor impairment under certain pathological conditions such as chronic musculoskeletal head-neck disorders, associated with stress conditions.
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Affiliation(s)
- S Roatta
- Physiology Division, Department of Neuroscience, Medical School, University of Turin, c.so Raffaello 30, 10125 Turin, Italy.
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40
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Masuda Y, Kim SK, Kato T, Iida S, Yoshida A, Tachibana Y, Morimoto T. Different corticostriatal projections from two parts of the cortical masticatory area in the rabbit. Exp Brain Res 2004; 161:397-404. [PMID: 15502983 DOI: 10.1007/s00221-004-2073-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2004] [Accepted: 07/16/2004] [Indexed: 11/26/2022]
Abstract
The cortical masticatory area (CMA) elicits rhythmic jaw movements in response to repetitive stimulation and is involved in the control of mastication. Based on jaw movement patterns, the CMA is divided into two parts. One is the part of the CMA in which a T-pattern similar to jaw movements during food transport in natural mastication is evoked by electrical stimulation. The other is more dorsomedially located, and during chewing a C-pattern similar to jaw movements can be induced. However, it is still not known which region of the putamen receives projections from the CMA and whether projections originate from both parts of the CMA. In this study, electrophysiological and histological experiments were undertaken in rabbits to investigate projections from the CMA to the putamen. Both experiments showed that the ventral region of the putamen received projections from the CMA. The density of the projections from the CMA area inducing the T-pattern seemed to be higher than that from the area inducing the C-pattern. Furthermore, the peak latency of the evoked potentials from stimulation of the CMA area inducing the T-pattern was shorter than that from stimulation of the area inducing the C-pattern. The data obtained from the present study indicate the functional role of the ventral region of the putamen in the regulation of mastication, and further suggest that the corticostriatal pathway is involved in the transition between behavioral jaw movement patterns.
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Affiliation(s)
- Yuji Masuda
- Department of Oral Physiology, Graduate School of Dentistry, Osaka University, Osaka, Japan.
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41
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Inoue M, Ariyasinghe S, Yamamura K, Harasawa Y, Yamada Y. Extrinsic tongue and suprahyoid muscle activities during mastication in freely feeding rabbits. Brain Res 2004; 1021:173-82. [PMID: 15342265 DOI: 10.1016/j.brainres.2004.06.047] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/25/2004] [Indexed: 10/26/2022]
Abstract
To evaluate the coordination of tongue and suprahyoid muscle activities during natural mastication, electromyograms (EMGs) of jaw-closer, jaw-opener, suprahyoid (mylohyoid, MH), tongue-retractor (styloglossus, SG) and tongue-protractor (genioglossus, GG) muscles were recorded as well as the jaw-movement trajectories in vertical and horizontal axes in awake rabbits. Each masticatory cycle had three components including the fast-closing (FC), slow-closing (SC) and opening (Op) phases. The duration of the SC phase was much longer during pellet chewing while the durations of the FC and Op phases were much shorter during pellet chewing than bread or banana chewing. The jaw movements during banana chewing had a small amplitude of lateral excursion and a large amplitude of gape as compared with those during pellet and bread chewing. The MH muscle exhibited double-peaked EMG bursts during the Op phase. The MH bursts in the late part of the Op phase were dominant on the non-chewing side during pellet and bread chewing. The SG muscle also exhibited double-peaked EMG bursts. During pellet and bread chewing, the SG bursts during the SC phase were significantly larger on the chewing side than the non-chewing side. These bursts were also dominant during pellet chewing as compared with banana chewing. There was little difference in the GG bursts between the chewing and non-chewing sides or among the foods. Our results suggest that patterns of the MH and SG muscle activity are affected by the peripheral inputs and/or chewing patterns while those of the GG muscle activity was less modulated regardless of the consistency of foods.
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Affiliation(s)
- Makoto Inoue
- Division of Oral Physiology, Department of Oral Biological Science, Niigata University, Graduate School of Medical and Dental Sciences, 2-5274 Gakkocho-dori, Niigata 951-8514, Japan.
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42
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Okayasu I, Yamada Y, Maeda T, Yoshida N, Koga Y, Oi K. The involvement of brain-derived neurotrophic factor in the pattern generator of mastication. Brain Res 2004; 1016:40-7. [PMID: 15234250 DOI: 10.1016/j.brainres.2004.04.061] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/20/2004] [Indexed: 10/26/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) is a family of neurotrophins that plays crucial roles in neural development, survival, maintenance and regeneration both in central and peripheral nervous systems. To examine the effects of BDNF on mastication, jaw movement trajectories and masticatory muscle activities were electrophysiologically investigated in BDNF-deficient mice, compared with those of littermate wild-type mice. BDNF-deficient mice showed less number of chewing strokes and more irregular chewing pattern during mastication than wild-type mice. Masseter muscle activities of BDNF-deficient mice exhibited smaller values than those of wild-type mice. No significant difference in the cycle duration existed between these two types of the mice. These results indicate that the burst pattern is more susceptible to peripheral sensory inputs than the timing and suggest the involvement of BDNF in the control of jaw movement.
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Affiliation(s)
- Ichiro Okayasu
- Division of Clinical Physiology, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki 852-8588, Japan.
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43
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BOSMAN FREDERIK, BILT ANDRIES, ABBINK JANH, GLAS HILBERTW. NEUROMUSCULAR CONTROL MECHANISMS IN HUMAN MASTICATION. J Texture Stud 2004. [DOI: 10.1111/j.1745-4603.2004.tb00833.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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44
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Ogawa A, Morimoto T, Hu JW, Tsuboi Y, Tashiro A, Noguchi K, Nakagawa H, Iwata K. Hard-food mastication suppresses complete Freund's adjuvant-induced nociception. Neuroscience 2003; 120:1081-92. [PMID: 12927213 DOI: 10.1016/s0306-4522(03)00214-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The effect of food hardness during mastication on nociceptive transmission in the spinal cord was studied by analyzing complete Freund's adjuvant (CFA) induced nocifensive behavior and Fos expression. The behavioral study showed that the shortening of the withdrawal latency following CFA injection into the hind paw was depressed after a change in the given food hardness from soft to hard. The depression of nocifensive behavior in the rats with hard food was reversed after i.v. injection of naloxone. Fos protein-like immunoreactive cells (Fos protein-LI cells) were expressed in the superficial and deep laminae of the L4-6 spinal dorsal horn after s.c. injection of CFA into the hind paw during soft food mastication. The number of Fos protein-LI cells was decreased in the rats with hard food mastication followed by soft food. This reduction of Fos protein-LI cells following change in food hardness was reversed after i.v. application of naloxone. Furthermore, the depression of Fos protein-LI cells following hard food intake was significantly inhibited after bilateral inferior alveolar nerve transection or bilateral ablation of the somatosensory cortex. These findings suggest that the change in food hardness during mastication might drive an opioid descending system through the trigeminal sensory pathway and somatosensory cortex resulting in an antinociceptive effect on chronic pain. However, IAN transection and cortical ablation did not induce 100% reversal of Fos expression, suggesting other than trigeminal sensory system may be involved in this phenomena, such as the pathway through the brainstem reticular formation.
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Affiliation(s)
- A Ogawa
- Department of Dental Anesthesiology, Osaka University, Graduate School, Faculty of Dentistry, Suita, 565-0871, Osaka, Japan
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45
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Zhang W, Kobayashi M, Moritani M, Masuda Y, Dong J, Yagi T, Maeda T, Morimoto T. An involvement of trigeminal mesencephalic neurons in regulation of occlusal vertical dimension in the guinea pig. J Dent Res 2003; 82:565-9. [PMID: 12821720 DOI: 10.1177/154405910308200715] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Although the occlusal vertical dimension (OVD) is strictly controlled, the neuronal mechanism of its regulation is still unclear. We hypothesize that neurons in the trigeminal mesencephalic nucleus (MesV) play an important role in the regulation of the OVD, because the MesV receives the projection from jaw-closing muscle spindles and periodontal mechanoreceptors. We measured the temporal OVD change in the guinea pig to study the effects of MesV lesions on the OVD. OVD-raised animals without MesV lesions showed a rapid OVD decrease to the same level as that in naïve controls, followed by an OVD increase after the OVD-raising appliance was removed. In contrast, OVD-raised animals with MesV lesions showed only a slight decrease in the OVD for 15 days after removal of the appliance, and then the OVD increased. The time-course of OVD development in normal-bite animals with MesV lesions was similar to that of naïve controls. These results suggest that MesV neurons are involved in OVD regulation.
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Affiliation(s)
- W Zhang
- Department of Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Japan
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46
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Nasution FH, Toda K, Soma K. Functional maturation of periodontal mechanoreceptors during development in rats. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2002; 139:307-12. [PMID: 12480146 DOI: 10.1016/s0165-3806(02)00543-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The influence of development on periodontal mechanoreceptors (PMRs) was investigated in four groups of male Wistar albino rats aged 1, 3, 5 weeks and 6 months using an in vitro jaw-nerve preparation. The mean values of conduction velocities of the nerve innervating PMRs in 5-week and 6-month groups were significantly higher than those in the other two groups. All fiber types obtained in the 5-week and 6-month groups were Abeta. The mechanical thresholds of 5-week and 6-month groups were significantly higher than those of 1- and 3-week groups. These data suggest that the response properties of rat's PMRs are matured by 5-week after birth, when functional molar occlusion and transition of dietary contents from liquid to hard-diet can be achieved.
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Affiliation(s)
- Fajar Hamonangan Nasution
- Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Science, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
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