Regulation of masticatory force during cortically induced rhythmic jaw movements in the anesthetized rabbit

O. Hidaka, T. Morimoto, Y. Masuda, T. Kato, R. Matsuo, T. Inoue, M. Kobayashi, K. Takada

Research output: Contribution to journalArticle

76 Citations (Scopus)

Abstract

To examine the relationships between masticatory force, electromyogram (EMG) of masticatory muscles, and jaw movement pattern, we quantitatively evaluated the effects of changing hardness of a chewing substance on these three variables. Cortically induced rhythmic jaw movements of a crescent- shaped pattern were induced by electrical stimulation of the cerebral cortical masticatory area in the anesthetized rabbit. The axially directed masticatory force was recorded with a small force-displacement transducer mounted on the ground surface of the lower molars. EMGs were recorded from the masseter and digastric muscles simultaneously with jaw movements. Five test strips of polyurethane foam of different hardness were prepared and inserted between the upper molar and the transducer during the movements. The peak, impulse, and buildup speed of the masticatory force increased with strip hardness, whereas duration of the exerted force did not vary with strip hardness. The integrated activity and duration of the masseteric EMG bursts also increased with strip hardness. The integrated EMG activity of the digastric bursts was weakly related to strip hardness, whereas the duration was not. The minimum gape increased with strip hardness, but the maximum gape did not. The horizontal excursion of the jaw did not vary in a hardness- dependent manner, although it was greater in the cycles with strip application than in the cycles without strip application. Deprivation of periodontal sensation by cutting the nerves to the teeth reduced the buildup speed of the force, maximum gape, net gape, and horizontal jaw movements. The denervation also elongated the force duration and that of masseteric EMG bursts. However, the rate of the hardness-dependent changes in the above parameters did not alter after denervation. The latency of the masseteric EMG response to strip application was evaluated before and after denervation. In both conditions, it was ≤6 ms in ~70% of the cycles and

Original languageEnglish
Pages (from-to)3168-3179
Number of pages12
JournalJournal of Neurophysiology
Volume77
Issue number6
Publication statusPublished - 1997
Externally publishedYes

Fingerprint

Bite Force
Hardness
Jaw
Rabbits
Electromyography
Denervation
Transducers
Masticatory Muscles
Masseter Muscle
Mastication
Electric Stimulation
Tooth

ASJC Scopus subject areas

  • Physiology
  • Neuroscience(all)

Cite this

Hidaka, O., Morimoto, T., Masuda, Y., Kato, T., Matsuo, R., Inoue, T., ... Takada, K. (1997). Regulation of masticatory force during cortically induced rhythmic jaw movements in the anesthetized rabbit. Journal of Neurophysiology, 77(6), 3168-3179.

Regulation of masticatory force during cortically induced rhythmic jaw movements in the anesthetized rabbit. / Hidaka, O.; Morimoto, T.; Masuda, Y.; Kato, T.; Matsuo, R.; Inoue, T.; Kobayashi, M.; Takada, K.

In: Journal of Neurophysiology, Vol. 77, No. 6, 1997, p. 3168-3179.

Research output: Contribution to journalArticle

Hidaka, O, Morimoto, T, Masuda, Y, Kato, T, Matsuo, R, Inoue, T, Kobayashi, M & Takada, K 1997, 'Regulation of masticatory force during cortically induced rhythmic jaw movements in the anesthetized rabbit', Journal of Neurophysiology, vol. 77, no. 6, pp. 3168-3179.
Hidaka O, Morimoto T, Masuda Y, Kato T, Matsuo R, Inoue T et al. Regulation of masticatory force during cortically induced rhythmic jaw movements in the anesthetized rabbit. Journal of Neurophysiology. 1997;77(6):3168-3179.
Hidaka, O. ; Morimoto, T. ; Masuda, Y. ; Kato, T. ; Matsuo, R. ; Inoue, T. ; Kobayashi, M. ; Takada, K. / Regulation of masticatory force during cortically induced rhythmic jaw movements in the anesthetized rabbit. In: Journal of Neurophysiology. 1997 ; Vol. 77, No. 6. pp. 3168-3179.
@article{39905090745647cbbb8469e8ca48994b,
title = "Regulation of masticatory force during cortically induced rhythmic jaw movements in the anesthetized rabbit",
abstract = "To examine the relationships between masticatory force, electromyogram (EMG) of masticatory muscles, and jaw movement pattern, we quantitatively evaluated the effects of changing hardness of a chewing substance on these three variables. Cortically induced rhythmic jaw movements of a crescent- shaped pattern were induced by electrical stimulation of the cerebral cortical masticatory area in the anesthetized rabbit. The axially directed masticatory force was recorded with a small force-displacement transducer mounted on the ground surface of the lower molars. EMGs were recorded from the masseter and digastric muscles simultaneously with jaw movements. Five test strips of polyurethane foam of different hardness were prepared and inserted between the upper molar and the transducer during the movements. The peak, impulse, and buildup speed of the masticatory force increased with strip hardness, whereas duration of the exerted force did not vary with strip hardness. The integrated activity and duration of the masseteric EMG bursts also increased with strip hardness. The integrated EMG activity of the digastric bursts was weakly related to strip hardness, whereas the duration was not. The minimum gape increased with strip hardness, but the maximum gape did not. The horizontal excursion of the jaw did not vary in a hardness- dependent manner, although it was greater in the cycles with strip application than in the cycles without strip application. Deprivation of periodontal sensation by cutting the nerves to the teeth reduced the buildup speed of the force, maximum gape, net gape, and horizontal jaw movements. The denervation also elongated the force duration and that of masseteric EMG bursts. However, the rate of the hardness-dependent changes in the above parameters did not alter after denervation. The latency of the masseteric EMG response to strip application was evaluated before and after denervation. In both conditions, it was ≤6 ms in ~70{\%} of the cycles and",
author = "O. Hidaka and T. Morimoto and Y. Masuda and T. Kato and R. Matsuo and T. Inoue and M. Kobayashi and K. Takada",
year = "1997",
language = "English",
volume = "77",
pages = "3168--3179",
journal = "Journal of Neurophysiology",
issn = "0022-3077",
publisher = "American Physiological Society",
number = "6",

}

TY - JOUR

T1 - Regulation of masticatory force during cortically induced rhythmic jaw movements in the anesthetized rabbit

AU - Hidaka, O.

AU - Morimoto, T.

AU - Masuda, Y.

AU - Kato, T.

AU - Matsuo, R.

AU - Inoue, T.

AU - Kobayashi, M.

AU - Takada, K.

PY - 1997

Y1 - 1997

N2 - To examine the relationships between masticatory force, electromyogram (EMG) of masticatory muscles, and jaw movement pattern, we quantitatively evaluated the effects of changing hardness of a chewing substance on these three variables. Cortically induced rhythmic jaw movements of a crescent- shaped pattern were induced by electrical stimulation of the cerebral cortical masticatory area in the anesthetized rabbit. The axially directed masticatory force was recorded with a small force-displacement transducer mounted on the ground surface of the lower molars. EMGs were recorded from the masseter and digastric muscles simultaneously with jaw movements. Five test strips of polyurethane foam of different hardness were prepared and inserted between the upper molar and the transducer during the movements. The peak, impulse, and buildup speed of the masticatory force increased with strip hardness, whereas duration of the exerted force did not vary with strip hardness. The integrated activity and duration of the masseteric EMG bursts also increased with strip hardness. The integrated EMG activity of the digastric bursts was weakly related to strip hardness, whereas the duration was not. The minimum gape increased with strip hardness, but the maximum gape did not. The horizontal excursion of the jaw did not vary in a hardness- dependent manner, although it was greater in the cycles with strip application than in the cycles without strip application. Deprivation of periodontal sensation by cutting the nerves to the teeth reduced the buildup speed of the force, maximum gape, net gape, and horizontal jaw movements. The denervation also elongated the force duration and that of masseteric EMG bursts. However, the rate of the hardness-dependent changes in the above parameters did not alter after denervation. The latency of the masseteric EMG response to strip application was evaluated before and after denervation. In both conditions, it was ≤6 ms in ~70% of the cycles and

AB - To examine the relationships between masticatory force, electromyogram (EMG) of masticatory muscles, and jaw movement pattern, we quantitatively evaluated the effects of changing hardness of a chewing substance on these three variables. Cortically induced rhythmic jaw movements of a crescent- shaped pattern were induced by electrical stimulation of the cerebral cortical masticatory area in the anesthetized rabbit. The axially directed masticatory force was recorded with a small force-displacement transducer mounted on the ground surface of the lower molars. EMGs were recorded from the masseter and digastric muscles simultaneously with jaw movements. Five test strips of polyurethane foam of different hardness were prepared and inserted between the upper molar and the transducer during the movements. The peak, impulse, and buildup speed of the masticatory force increased with strip hardness, whereas duration of the exerted force did not vary with strip hardness. The integrated activity and duration of the masseteric EMG bursts also increased with strip hardness. The integrated EMG activity of the digastric bursts was weakly related to strip hardness, whereas the duration was not. The minimum gape increased with strip hardness, but the maximum gape did not. The horizontal excursion of the jaw did not vary in a hardness- dependent manner, although it was greater in the cycles with strip application than in the cycles without strip application. Deprivation of periodontal sensation by cutting the nerves to the teeth reduced the buildup speed of the force, maximum gape, net gape, and horizontal jaw movements. The denervation also elongated the force duration and that of masseteric EMG bursts. However, the rate of the hardness-dependent changes in the above parameters did not alter after denervation. The latency of the masseteric EMG response to strip application was evaluated before and after denervation. In both conditions, it was ≤6 ms in ~70% of the cycles and

UR - http://www.scopus.com/inward/record.url?scp=0030791212&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0030791212&partnerID=8YFLogxK

M3 - Article

VL - 77

SP - 3168

EP - 3179

JO - Journal of Neurophysiology

JF - Journal of Neurophysiology

SN - 0022-3077

IS - 6

ER -