Shibusawa Mami, Takeda Tomotaka, Nakajima Kazunori, Ishigami Keiichi, Sakatani Kaoru
Department of Sports Dentistry, Tokyo Dental College, Mihama-ku, Chiba-shi, Chiba 261-8502, Japan.
Neurosci Lett. 2009 Jan 9;449(2):98-102. doi: 10.1016/j.neulet.2008.10.073. Epub 2008 Oct 25.
The purpose of this study was to elucidate the influence of clenching and clenching intensity on oxygenated hemoglobin (OxyHb) levels in regional cerebral blood flow as an indicator of brain activity in the primary motor and sensory cortices. Functional near-infrared spectroscopy (fNIRS) was used to minimize the effect of clenching-associated muscle activity in eight healthy subjects. Subjects were required to clench at 20%, 50% and 80% of maximum clenching force. To minimize the effect of temporal muscle activity on the working side of the jaw, the fNIRS probes were positioned contralaterally, in the left temporal region. Activation of the primary motor and sensory cortices with clenching was noted in all subjects, irrespective of intensity of clenching. A significant increase was observed in OxyHb in the primary motor cortex between at 80% and both 20% and 50% clenching intensity. In the primary sensory cortex, OxyHb showed a significant increase between all levels of clenching intensity. The results suggest that clenching elicits activation of both the primary motor and sensory cortices, and that intensity of clenching influences activation levels in the brain.
本研究的目的是阐明咬紧牙关及咬紧强度对局部脑血流中氧合血红蛋白（OxyHb）水平的影响，以此作为初级运动皮层和感觉皮层脑活动的指标。在八名健康受试者中，使用功能近红外光谱技术（fNIRS）将咬紧牙关相关的肌肉活动影响降至最低。受试者需以最大咬紧力的20%、50%和80%进行咬紧。为将颞肌活动对下颌工作侧的影响降至最低，fNIRS探头置于对侧，即左侧颞区。所有受试者在咬紧牙关时均观察到初级运动皮层和感觉皮层的激活，无论咬紧强度如何。在初级运动皮层，与80%咬紧强度相比，20%和50%咬紧强度时氧合血红蛋白均显著增加。在初级感觉皮层，氧合血红蛋白在所有咬紧强度水平之间均显著增加。结果表明，咬紧牙关会引发初级运动皮层和感觉皮层的激活，且咬紧强度会影响大脑的激活水平。
