Neural substrates of taste, smell and flavor in humans

描述（由申请人提供）：我们的首要目标是定义人类味觉和风味的神经底物。该应用程序用于一个项目，该项目将使用功能性磁共振成像（fMRI）来测量健康人类志愿者受试者对单独呈现的味道和气味呈现的味道的大脑反应。味觉的神经基质必须编码味觉的三个主要感知维度，即强度、情感和质量。以前的研究比较愉快和不愉快的味道没有等同的刺激强度，也没有研究测量大脑对不同浓度的相同味道的反应。我们的第一个具体目标是确定编码味觉强度与味觉愉悦/不愉悦的大脑区域。我们将向受试者提供两种浓度的令人愉快和不愉快的味道，同时用功能性磁共振成像测量他们的大脑反应。然后将进行分析，以隔离大脑对强度的反应，而不考虑情感效价和影响，而不考虑强度。我们的第二个目标是使用功能磁共振成像来研究大脑相关的同时呈现的味道和气味与独立呈现的味道或气味。一致（香草气味与甜味）和不一致（香草气味与咸味）的味道/气味对将被提出调查的经验整合的效果。此外，还将研究气味呈现模式（鼻前与鼻后递送）。当味觉和嗅觉自然共存时，气味通过鼻后途径被感知。因此，我们预测差异整合的气味与味道有利于鼻后途径。了解味觉和风味的神经相关性提供了一种机制，通过这种机制可以在健康和疾病中探索边缘系统功能。例如，fMRI信号对味觉浓度的响应函数可以被用作边缘系统响应的客观探针，类似于闪烁棋盘被用于定义视觉皮层中的fMRI信号的特征。此外，味觉强度反应的成像研究也可用于证明怀疑边缘系统受累的患者群体中边缘系统功能的完整性（例如，阿尔茨海默病）或可能对食物刺激有异常反应的患者（例如，贪食症）。这项研究也将提供重要的信息到多模态感觉整合的性质。

DESCRIPTION (provided by applicant): Our overarching goal is to define the neural substrates of taste and flavor in humans. This application is for a project that will use functional magnetic resonance imaging (fMRI) to measure brain response in healthy human volunteer subjects to tastes presented in isolation and tastes presented with odors. The neural substrates of taste must code for three major perceptual dimensions of taste; namely, intensity, affect, and quality. Previous studies comparing pleasant to unpleasant taste have not equated stimuli for intensity and no study has measured brain response to the different concentrations of the same taste. Our first specific aim is to determine brain regions coding for taste intensity versus taste pleasantness/unpleasantness. We will present subjects with two concentrations each of a pleasant and unpleasant taste while their brain response is measured with fMRI. Analyses will then be performed to isolate the brain response to intensity regardless of affective valence and affect regardless of intensity. Our second aim is to use fMRI to investigate brain correlates of simultaneous presentation of taste and smell versus independent presentation with either a taste or a smell. Congruent (vanilla odor with sweet taste) and incongruent (vanilla odor with salty taste) taste/smell pairs will be presented to investigate the effect of experience on integration. Additionally, mode of odor presentation (orthonasal versus retronasal delivery) will also be investigated. When taste and smell co-occur naturally the odor is perceived via the retronasal route. We thus predict differential integration of odor with taste favoring the retronasal route. Understanding the neural correlates of taste and flavor offers a mechanism by which limbic system function can be probed in health and disease. For example, the response function of the fMRI signal to taste concentration may be used as an objective probe for limbic system response in an analogous way that the flickering checkerboard has been used to define the characteristics of the fMRI signal in the visual cortex. Furthermore, imaging studies of taste intensity response may also be used to demonstrate the integrity of limbic system function in patient populations with suspected limbic system involvement (e.g., Alzheimer's disease) or patients who may respond abnormally to food stimuli (e.g., bulimia). This research will also provide important information into the nature of polymodal sensory integration.