Cognitive and affective influences on taste processing

描述（由申请人提供）：这是一个项目的申请，将使用功能磁共振成像来研究人类大脑中味觉的中心表征。有两个具体的目标。具体目的一是评估一项任务的表现是否会影响大脑对感官刺激的反应。我们知道在皮层味觉区有预期神经元和味觉反应神经元穿插在一起我们知道这些皮层味觉区参与了情感决策。因此，一项任务的执行，如判断愉悦或检测味道的存在，很可能会影响味觉神经元的反应，或在味觉区域内唤起可能阻碍或与检测味道反应相互作用的反应。因此，显然需要系统地研究如何判断味觉的感知属性与味觉反应之间的相互作用。具体目的II是评估一般预测，即当强度和情感值被控制时，质量特异性反应可以被隔离，并且这些反应可以根据质量的生理意义在功能上分组。尽管味觉-质量编码的问题一直主导着大鼠和灵长类动物的味觉电生理工作，但迄今为止，还没有研究在人类中解决这个问题。由于味觉强度、情感和质量编码可能存在重叠的表征，我们建议在系统地操纵或控制刺激的强度和情感价值的同时，检查大脑对味觉质量的反应。因为情感价值可以是刺激内在的，或者是内部状态变化的结果，我们将检验这样一个假设，即虽然甜味的内在愉悦可能会影响质量编码，但质量编码应该独立于与饱足感相关的愉悦的短暂变化。我们将使用标准的功能磁共振成像以及两种新技术，功能磁共振成像适应和有效的连通性分析，来检查质量是否表现为空间分离的反应（例如化学），空间重叠但不同的神经元群体反应或皮层味觉区域网络内的独特互连模式。这项研究将提供有关人类味觉的基本信息，并将为未来研究肥胖和饮食、药物或酒精障碍患者的味觉加工提供重要的基线数据。

DESCRIPTION (provided by applicant): This is an application for a project that will use fMRI to investigate central representation of taste in the human brain. There are 2 specific aims. Specific aim I is to evaluate whether the performance of a task influences brain responses to sapid stimuli. We know that there are anticipatory neurons interspersed with taste-responsive neurons in the cortical gustatory areas and we know that these cortical taste regions participate in affective decision-making. Therefore, it is very likely that performance of a task, such as judging pleasantness or detecting the presence of a taste, affects the response of gustatory neurons or evokes a response within the gustatory areas that could hinder or interact with detection of the response to taste. Systematic investigation of how judging perceptual attributes of a taste interact with the gustatory response is therefore clearly needed. Specific aim II is to evaluate the general prediction that quality-specific responses can be isolated when intensity and affective value are controlled, and that such responses can be functionally grouped according the physiological meaning of the quality. Although the issue of taste-quality coding has dominated the rat and primate electrophysiological work in gustation, to date, no study has addressed this issue in humans. Since there is likely to be overlapping representation of taste intensity, affect, and quality coding, we propose to examine brain responses to taste quality while systematically manipulating or controlling for the intensity and affective value of the stimulus. Because affective value can be intrinsic to the stimulus, or the result of changes in internal state we will test the hypothesis that while the intrinsic pleasantness of a sweet taste may influence quality coding, quality coding should be independent from transient changes in pleasantness associated with satiety. We will use standard fMRI as well as 2 novel techniques, fMRI-adaptation, and effective connectivity analyses, to examine if quality is represented as spatially segregated responses (e.g. chemotopy), spatially overlapping but distinct neuronal population responses or as unique patterns of interconnectivity within a network of cortical gustatory areas. This research will provide fundamental information about human gustation and it will provide important baseline data for future studies of gustatory processing in the obese and individuals with an eating, drug or alcohol disorder.