@article{oai:niigata-u.repo.nii.ac.jp:00003654,
 author = {五十嵐, 直子 and 山村, 健介 and 山田, 好秋 and 河野, 正司},
 issue = {2},
 journal = {日本顎口腔機能学会雑誌, 日本顎口腔機能学会雑誌},
 month = {Mar},
 note = {It has been shown in humans that during mastication the head moves rhythmically and coordinately with jaw movements. A neurophysiological explanation for the mechanism of this finding has not been given so far, matter which became the objective of this study. Head movement and EMG of neck(sternomastoid and splenius capitis)muscles were recorded simultaneously in awake unrestrained rabbits during bread and raw rice chewing. Also, EMG activity was recorded in anesthetized rabbits from the sternomastoid and semispinalis capitis muscles during cortically evoked fictive mastication. In voluntary mastication, the rabbits moved their heads rhythmically in a cycle similar to their chewing cycle and in an opposite direction to the jaw movement, Rhythmical EMG activity was observed in the sternomastoid, which showed biphasic activity in the jaw closing and opening movements during bread chewing ; however, during raw rice chewing it was active only in the jaw closing movements. The splenius muscle showed tonic activity and no rhythmic activity was observed regardless of the test food used. In cortically evoked fictive mastication the sternomastoid was activated only in the jaw closing movements. This activity increased when biting on wooden sticks between opposing molars took place. In the semispinalis capitis tonic activity was observed in both events. Rhythmical head movement coordinated with jaw movement was observed during mastication not only in humans but also in rabbits ; this observation indicates that rabbits are appropriate animal models to study head movement during mastication. From the results of this experiment we suggest that the sternomastoid may be reflexly coactivated with masticatory muscles by peripheral inputs such as periodontal afferents and afferents from propioceptors regulating sense of position during jaw opening and closing movements., ヒトにおいて，咀嚼時には頭部は下顎運動と協調してリズミカルに動いていることが報告されている．この咀嚼時の頭部運動のメカニズムを調べる目的で，覚醒無拘束のウサギを用いて，性状の異なる2種の試料（パン，生米）を咀嚼している際の頭部運動と頸筋（胸骨乳突筋，頭板状筋）のEMGを記録した．また，ウレタン麻酔を施したウサギを用いて，皮質誘発性咀嚼様運動時に頸筋（胸骨乳突筋，頭半棘筋）のEMGを記録した．覚醒咀嚼時には，頭部が下顎運動と同じ周期でリズミカルに動いており，その垂直的な運動方向は下顎運動と反対であった．同時に，胸骨乳突筋には試料に応じて異なるリズミカルな活動が観察された．パン咀嚼時には開口時と閉口時の二相性に活動し，生米咀嚼時には閉口時のみに活動した．頭板状筋は持続的に活動しており，活動に明瞭なリズム性は認められなかった．麻酔下の皮質誘発性咀嚼様運動時には，胸骨乳突筋は閉口時にのみ活動を示し，臼歯で木片を咬合させると活動が増強した．頭半棘筋は持続的に活動しており，活動にリズム性は見られなかった．覚醒咀嚼時に観察されたリズミカルな頭部運動が，ヒトと同様な様相を呈したことから，ウサギは咀嚼時頭部運動の実験モデルとして有用であることが示された．また，咀嚼リズムに同期してリズミカルに活動した胸骨乳突筋は，咀嚼筋や頸部の固有感覚受容器あるいは歯根膜などからの末梢性入力によって活動が増強され，反射性に活動することが示唆された．一方，頭板状筋，頭半棘筋活動の咀嚼運動時におけるリズム性は明瞭でなく，頭部運動との関連は明らかでなかった．},
 pages = {191--196},
 title = {咀嚼運動時に観察されるウサギ頚筋の活動},
 volume = {4},
 year = {1998}
}