Taste and Oral Sensory Processing in the Brain

风味是指指导影响营养状况的摄入决定，并可能导致健康问题 比如肥胖症和糖尿病。风味涉及多个感官通路的作用，包括 引起味觉的神经回路，如甜和苦，以及那些引起口腔感觉的神经回路。 躯体感觉由食物引起的躯体感觉线索可以包括温度和疼痛（例如，辣椒 烧伤）。第五颅骨的电活动部分传递了口腔躯体感觉的神经信息 三叉神经系统的神经和大脑核团。大脑三叉神经通路在味觉中的作用 目前还不太清楚，许多问题仍然存在，包括中央三叉神经元如何传递信息 有害和无害的口腔温度拟议的研究将解决这个问题和其他问题 其长期目标是阐明口感觉三叉神经元如何参与和执行单峰 和与风味相关的多感官加工。具体目标#1将使用神经生理学记录， 单个三叉神经元在小鼠延髓测试的假设，异质亚群的 细胞区分有害和无害的口腔温度，重点是口腔的神经代表性， 降温细胞功能将通过使用逆向电激活来测量，以验证 记录神经元到臂旁核，参与整合和情感处理。到 定义到达不同类型的冷却响应orosensory细胞的传入输入，单位将进行测试， 介导温度感觉的瞬时受体电位（TRP）离子通道的化学激动剂， 伤害感受，并且还记录了遗传缺陷的小鼠与冷却有关的选择TRP通道 感觉。具体目标#2将测试这一假设，即臂旁核是一个大脑部位的逻辑 三叉神经和味觉的整合味觉和三叉神经通路之间的相互作用已被讨论， 虽然大脑神经元支持味觉和三叉神经感觉的合并， 信号仍然不确定。很少有解剖学和生理学数据表明味觉的趋同 而三叉神经通路则起源于臂旁核，这两个核在味觉中的作用是不同的 或疼痛处理。在这里，我们将使用神经生理学记录，刺激和光遗传学技术 它提供了快速和可逆的神经活动抑制，以剖析神经元投射是否以及如何 到达臂旁核中的味觉反应神经元。基因 TRP缺陷小鼠也将在记录研究中进行测试，以索引介导躯体感觉活动的受体 在臂旁味觉细胞中。最后，我们将应用光遗传学来评估初级三叉神经传入神经是如何 臂旁核与该结构中的味觉敏感神经元相互作用。总的来说，这些 研究的目的是利用小鼠神经回路的生理和分子分析来了解三叉神经是如何 神经元编码与味道相关的口腔感觉信息，并与味觉神经回路相互作用。

Flavor is implicated to guide ingestive decisions that impact nutritional status and can lead to health problems in humans, such as obesity and diabetes. Flavor involves the actions of multiple sensory pathways, including neural circuits that invoke taste sensations, such as sweet and bitter, and those that give rise to oral somatosensation. Somatosensory cues elicited by foods can include temperature and pain (e.g., chili pepper burn). Neural messages about oral somatosensation are partly signaled by electrical activity in the fifth cranial nerve and brain nuclei known as the trigeminal system. The involvement of brain trigeminal pathways in flavor is poorly understood and many questions remain, including how central trigeminal neurons signal information about noxious and innocuous oral temperature. The proposed research will address this and other questions with the long-term goal of elucidating how orosensory trigeminal neurons contribute to and perform unimodal and multisensory processing relevant to flavor. Specific Aim #1 will use neurophysiological recordings from single trigeminal neurons in the mouse medulla to test the hypothesis that heterogeneous subpopulations of cells distinguish noxious from innocuous oral temperatures, focusing on the neural representation of oral cooling. Cellular function will be gauged by using antidromic electrical activation to verify projections of recorded neurons to the parabrachial nucleus, which is involved with integrative and affective processing. To define afferent inputs that reach different types of cooling-responsive orosensory cells, units will be tested with chemical agonists of transient receptor potential (TRP) ion channels that mediate thermosensation and nociception, and also recorded from mice genetically deficient for a select TRP channel implicated for cooling sensation. Specific Aim #2 will test the hypothesis that the parabrachial nucleus is a brain site of logical trigeminal and taste integration. Interaction between taste and trigeminal pathways has been discussed to contribute to flavor perception, albeit brain neurons that support merger of gustatory and trigeminal sensory signals remain undefined. There are scant anatomical and physiological data to suggest convergence of taste and trigeminal pathways arises in the parabrachial nucleus, which has been studied for separate roles in taste or pain processing. Here, we will use neurophysiological recording, stimulation, and optogenetic techniques that afford rapid and reversible inhibition of neural activity to dissect whether and how neuronal projections from medullary trigeminal nuclei reach gustatory-responsive neurons in the parabrachial nucleus. Genetically TRP-deficient mice will also be tested in recording studies to index receptors mediating somatosensory activity in parabrachial gustatory cells. Finally, we will apply optogenetics to assess how primary trigeminal afferents that reach the parabrachial nucleus interact with gustatory-sensitive neurons in this structure. Overall, these studies aim to use physiological and molecular analyses of neural circuits in mice to understand how trigeminal neurons encode oral sensory information relevant to flavor and interact with neural circuits for taste.