Department of Oral and Maxillofacial Radiology, Kyushu University, Maidashi, Higashi-ku, Fukuoka, Japan.
Brain Res. 2011 Aug 11;1406:18-29. doi: 10.1016/j.brainres.2011.06.029. Epub 2011 Jun 24.
There are no credible data to support the notion that individual taste qualities have dedicated pathways leading from the tongue to the end of the pathway in the brain. Moreover, the insular cortex is activated not only by taste but also by non-taste information from oral stimuli. These responses are invariably excitatory, and it is difficult to determine whether they are sensory, motor, or proprioceptive in origin. Furthermore, umami is a more unfamiliar and complex taste than other basic tastes. Considering these issues, it may be effective to minimize somatosensory stimuli, oral movement, and psychological effects in a neuroimaging study to elicit cerebral activity by pure umami on the human tongue. For this purpose, we developed an original taste delivery system for functional magnetic resonance imaging (fMRI) studies for umami. Then, we compared the results produced by two authorized models, namely, the block design model and event-related design model, to decide the appropriate model for detecting activation by umami. Activation by the umami taste was well localized in the insular cortex using our new system and block design model analysis. The peaks of the activated areas in the middle insular cortex by umami were very close to another prototypical taste quality (salty). Although we have to carefully interpret the perceiving intensities and brain activations by taste from different sessions, this study design might be effective for detecting the accession area in the cortex of pure umami taste on the tongue.
没有可信的数据支持这样一种观点，即个体的味觉品质有专门的通路，从舌头延伸到大脑的末端。此外，脑岛皮层不仅被味觉激活，也被来自口腔刺激的非味觉信息激活。这些反应总是兴奋性的，很难确定它们是感觉的、运动的还是本体感觉的起源。此外，鲜味比其他基本味觉更陌生和复杂。考虑到这些问题，在神经影像学研究中，通过最小化体感刺激、口腔运动和心理效应来诱发人类舌头上纯粹鲜味的大脑活动，可能是有效的。为此，我们开发了一种用于功能性磁共振成像 (fMRI) 研究鲜味的原始味觉传递系统。然后，我们比较了两种授权模型（即块设计模型和事件相关设计模型）产生的结果，以确定检测鲜味激活的合适模型。使用我们的新系统和块设计模型分析，鲜味的味觉激活很好地定位于脑岛皮层。鲜味激活的中脑岛皮层的峰值非常接近另一种典型的味觉品质（咸）。尽管我们必须仔细解释来自不同阶段的味觉感知强度和大脑激活，但这种研究设计可能对检测舌头上纯粹鲜味的皮层进入区域有效。
