Study on the effect of mastication on memories and leaning-A possibility of trigger factor of dementia-

最近，一些研究人员报道，咀嚼能力受损可能是痴呆的触发因素之一。然而，关于咀嚼和认知功能之间的关系的研究很少。本研究的目的是探讨咀嚼与血流动力学的关系，这是我们保健和预防某些神经系统疾病的第一步。首先，为了选择性地监测脑血流灌注，我们研究了近红外光谱(NIRS)测量的人体头部光信号的一些特征，在坐姿下的测量方面具有其他方法无法比拟的优势。我们阐明了NIRS(时间分辨光谱法)在脑血流动力学监测中的作用和局限性。接下来，我们通过咀嚼NIRS检测了咀嚼和认知任务引起的Hb浓度的变化，通过做语言流利性任务，OXY-Hb在颞区(Brodmann‘s区9和46)增加，在顶叶区域降低，在额叶和顶叶区域观察到OXY-Hb的减少。我们可以假设这两个任务之间的激活区域是相似的。

Recently, some researchers have reported the possibility that impairment of ability for mastication was one of the trigger factors of dementia. There are, however, only a few studies on the relationship between mastication and cognitive function. The aim of this study is to investigate the relationship between mastication and hemodynamics, which is the first step toward our health care and the prevention of some neurological diseases.First, for selective monitoring of the cerebral perfusion, we studied some characteristics of optical signals measured from the human head by near-infrared spectroscopy(NIRS), which has some advantages over other methods in terms of, for example, the measurement under sitting on the seat. We clarified the usefulness and limitations of the NIRS(time-resolved spectroscopic method) for monitoring of cerebral hemodynamics.Next, we examined Hb concentration changes evoked by chewing and cognitive tasks using NIRS By chewing, oxy-Hb increased in the temporal area(Brodmann's Area 9 and 46) and decreased in the region of parietal By doing verbal fluency task, decreases of oxy-Hb in the regions of the frontal and parietal were observed. We can suppose that there is a similarity of activation area between the two tasks.