Chewing effects on intelligent activities

近年来，许多人致力于评估咀嚼与人脑血液循环之间的相互作用，结果表明，咀嚼诱导的脑神经元活动的年龄相关变化。在这项研究中，我们使用功能性磁共振成像（fMRI）来评估年龄对年轻成年人与咀嚼相关的大脑区域活动的影响（19-26岁），中年（42-55岁），在有节奏地咀嚼口香糖和不咀嚼口香糖的周期中使用fMRI，我们发现，在所有受试者中，咀嚼导致感觉运动皮层、小脑、丘脑、辅助运动区和小脑皮层的BOLD信号双侧增加，右侧前额叶区单侧增加。在前三个区域中，信号增加以年龄依赖的方式衰减，而在右前额叶区，则匡威。其余两个区域在年龄上无显著差异。这些结果表明，咀嚼可能对大脑皮层中与记忆相关的功能区域产生刺激，并且在图像编码过程中，咀嚼引起海马中BOLD信号的显著增加，而海马被认为是记忆形成不可或缺的脑区，与不咀嚼者相比，咀嚼参与了海马网络系统。此外，未戴全口义齿的老年人在戴全口义齿后2周，海马BOLD信号在图像编码时出现高值，提示咀嚼功能在老年人学习记忆的维持和/或恢复中起着重要作用。

In recent years, much effort has been devoted to evaluating the interaction between chewing and blood circulation in the human brain ; as a result, age-related changes of chewing-induced brain neuronal activity have been suggested. In this study, we used functional magnetic resonance imaging (fMRI) to assess the effect of aging on brain regional activity associated with chewing in young adult ( 19-26 yrs), middle-aged (42-55 yrs), and aged (65-73 yrs) healthy humans.Using fMRI during cycles of rhythmic gum-chewing and no chewing, we found that, in all subjects, chewing resulted in a bilateral increase in the BOLD signals in the sensorimotor cortex, cerebellum, thalamus, supplementary motor area, and insula, and a unilateral increase in the right prefrontal area. In the first three regions, the signal increases were attenuated in an age-dependent manner, whereas, in the right prefrontal area, the converse was seen. The remaining two regions showed no significant differences with ages. These findings suggest that chewing may stimulate functionally memory-related regions in the cerebra cortex.In addition, during picture encoding, chewing caused a significantly higher increase of the BOLD signals in the hippocampus, being believed to play an indispensable brain region for memory formation, in comparison with those without chewing, implying involvement of chewing in the hippocampal network system. Furthermore, two weeks after wearing the full dentures of the aged subjects who had never worn them, higher value of the hippocampal BOLD signals were caused during picture encoding.These results indicate that masticatory function plays a crucial role in maintaining and/or recovering learning and memory in the elderly.