Effect of Receptive Field on Bitter Taste Coding

描述（由申请人提供）：最近的行为和神经证据表明，一些苦味刺激可能能够激活啮齿动物口腔前部的离子通道，而其他非离子苦味刺激可能仅限于激活口腔后部区域。这一系列的实验旨在研究苦味的感觉是如何被中央味觉系统编码的，特别是关于这种信息是如何根据受刺激的感受野和所使用的苦味刺激的化学结构而变化的。这将通过记录孤立束核和臂旁核味觉区域单个神经元的动作电位来完成，同时用各种味觉刺激刺激更后方的感受野（即叶状和环状乳头）。尽管支配这些乳头的舌咽神经对苦味刺激高度敏感，但它们在CMS水平上对味觉感知的贡献尚未确定。这可能部分是由于需要额外的措施，包括缝线和移液管，来有效刺激这些感受野。还将进行一项心理物理实验，以便在中枢神经系统水平的反应和清醒动物的苦味感知之间得出相似之处。这将通过在用苦味刺激进行行为测试之前切断周围的味觉神经来完成，这样就可以确定由这些神经支配的味觉受体细胞的影响。虽然我们通常认为苦味的食物是有毒的，但一些富含维生素的食物，如西兰花和羽衣甘蓝，也被人类受试者描述为尝起来很苦。如果我们能更好地理解苦味是如何被味觉系统编码的，也许这些信息可以用来改善某些药物和/或健康食品的味道。

DESCRIPTION (provided by applicant): Recent behavioral and neural evidence suggests that some bitter stimuli may be capable of activating ion channels in the anterior portion of the oral cavity in rodents, while other nonionic bitter stimuli may be limited to activation of the posterior region of the mouth. This series of experiments is designed to examine how the sensation of bitterness is encoded by the central gustatory system, specifically with regard to how this information might change depending on the receptive fields stimulated and the chemical structure of bitter stimuli used. This will be accomplished by recording action potentials from single neurons in the gustatory regions of nucleus of the solitary tract and parabrachial nucleus, while stimulating the more posterior receptive fields (i.e. the foliate and circumvallate papillae) with a variety of taste stimuli. Although the glossopharyngeal nerve, which innervates these papillae, is highly sensitive to bitter stimuli, their contribution to taste perception at the level of the CMS has not been established. This may be due in part to the fact that additional measures, including sutures and pipettes, are necessary to effectively stimulate these receptive fields. A psychophysical experiment will also be performed so that parallels can be drawn between responses at the level of the CNS and bitter taste perception in awake animals. This will be accomplished by severing sets of peripheral gustatory nerves prior to behavioral testing with bitter stimuli so that the influence of taste receptor cells in the fields innervated by these nerves can be determined. Although we typically think of bitter-tasting foods as being toxic, a number of vitamin-rich foods, such as broccoli and kale, have also been described as tasting bitter by human subjects. If we can better understand how bitter taste is encoded by the gustatory system, perhaps this information could be used to improve the taste of certain medications and/or healthy foods.