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味道的神经底物。这一应用是为了一个项目，该项目将使用功能磁共振成像(FMRI)来测量健康的人类志愿者对孤立呈现的味道和伴随气味呈现的味道的大脑反应。味觉的神经底物必须编码味觉的三个主要感知维度，即强度、情感和质量。以前比较愉快和不愉快味道的研究没有将刺激强度等同于刺激，也没有研究测量大脑对相同味道的不同浓度的反应。我们的第一个具体目标是确定大脑中编码味觉强度与味觉愉悦/不愉悦的区域。我们将向受试者呈现两种浓度，每种浓度分别是愉快和不愉快的味道，而他们的大脑反应是通过功能磁共振成像来测量的。然后将进行分析，以分离大脑对强度的反应，而不考虑情感价态和影响，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同时呈现味觉和嗅觉与单独呈现味觉或气味的大脑相关性。相同的(香草气味和甜味)和不一致的(香草气味和咸味)味道/气味对将被提出，以考察经验对整合的影响。此外，还将调查气味呈现的方式(正鼻和逆鼻传递)。当味觉和嗅觉自然地同时出现时，气味是通过鼻后通路感知的。因此，我们预测气味和味道的不同整合有利于后鼻道。了解味觉和味觉之间的神经联系提供了一种机制，可以用来探讨边缘系统在健康和疾病中的功能。例如，fMRI信号对味觉浓度的响应函数可以用作边缘系统响应的客观探针，类似于已经使用闪烁棋盘来定义视觉皮质中的fMRI信号的特征的方式。此外，味觉强度反应的成像研究也可以用来证明疑似边缘系统受累的患者群体(例如阿尔茨海默病)或可能对食物刺激做出异常反应的患者(例如暴食症)边缘系统功能的完整性。这项研究还将为了解多通道感觉整合的性质提供重要信息。

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.