Oral Somesthesis and Taste

这个项目的长期目标是了解躯体感觉和味觉系统是如何共同作用产生口感和味道的，这一目标将通过利用最近的三项心理物理学发现来实现，这三项发现为躯体感觉刺激如何影响味觉提供了新的见解。首先，将对热味现象进行研究，在热味现象中，仅由温度就可以诱导出味道。特别令人感兴趣的是热味的个体和空间差异的来源，热味和化学味之间的相互作用，以及热味的空间和时间特征，因为它们与热和冷的敏感性有关。其次，我们将研究短暂的冷刺激对舌头前部“幽灵”味觉的诱导和感知。这些冷诱导幻象(CIP)是在冷刺激后而不是在冷刺激期间被感知的，并且定位在远离降温的地方而不是在降温的地方。实验被用来检验这一假说，即当口腔感觉系统内部和之间的紧张抑制被冷块打断时，可逆地模拟临床上的发音障碍的CIPS就会出现。第三，初步观察表明，辣椒素，典型的三叉神经刺激物，可以在舌尖引起明显的苦味，而且那里的感觉刺激和对温暖的感觉都比舌尖弱得多。实验将调查一些有助于感知苦味的舌咽神经元是否对刺激物敏感，更广泛地说，舌背上的某些合成和味道之间的关系是不同的，这两种刺激都只由舌咽神经介导。总体而言，这些研究将促进我们对人类口腔感觉加工过程的理解，并提供有关感觉相互作用的数据，这些数据可能有助于理解某些类型的口腔感觉病理(例如，口腔感觉障碍)的来源。

The long-term goal of this project is to understand how the somesthetic and gustatory systems function together to produce oral sensations and flavors This goal will be pursued by taking advantage of three recent psychophysical findings that provide novel insights into how somatosensory stimulation can influence taste. First, studies will be conducted to investigate the phenomenon of thermal taste, in which tastes can be induced by temperature alone. Of particular interest are sources of individual and spatial variation in thermal taste, interactions between thermal taste and chemical taste, and the spatial and temporal characteristics of thermal tastes as they relate to the sensitivity to warmth and cold. Second, the induction and perception of 'phantom' tastes caused by brief bouts of cold stimulation on the front of the tongue will be investigated. These cold-induced phantoms (CIPs) are perceived after rather than during cold stimulation, and are localized away from rather than at the site of cooling. Experiments are proposed to test the hypothesis that CIPs, which reversibly mimic clinical dysgeusias, arise when putative tonic inhibition within and between oral sensory systems is interrupted by cold-block. Third, preliminary observations indicate that capsaicin, the prototypical "trigeminal" irritant, can evoke significant bitterness in the circumvallate region of the tongue, and that both sensory irritation and perception of warmth are much weaker there than on the tongue tip. Experiments will investigate the possibility that some glossopharyngeal neurons that contribute to perception of bitterness are sensitive to irritants, and more generally, that the relationship between somesthesis and taste is different on the back of the tongue, where both kinds of stimulation are mediated solely by the glossopharyngeal nerve. Overall, these studies will advance our understanding of oral sensory processing in humans as well as provide data on sensory interactions that may be helpful in understanding the source of certain types of oral sensory pathologies (e.g., dysgeusias).