Multimodal flavor integration and retronasal olfaction in the rat

描述(申请人提供)：多通道刺激如何整合是神经科学中的一个基本问题。这个问题与味觉特别相关，在味觉中，触摸、温度、味道和嗅觉总是在进食过程中同时发生刺激。人类的功能成像研究为多模式风味整合的神经基础提供了重要的见解，但无法解决需要更高分辨率或对神经活动或风味体验进行实验操作的问题。为了解决这些局限性，本项目的目标是建立一种大鼠模型，用于研究味道整合的神经机制。为了确定大鼠鼻后嗅觉是否像人类一样发生，第一项研究将使用光学钙成像技术测量清醒大鼠口服气味相关的各种行为在嗅球中诱发的时空模式。复古和正鼻气味之间的知觉相似性将同时进行调查。为了确定味道整合是否在老鼠身上感知地发生，第二项研究将调查条件性气味厌恶是否适用于味觉，以及条件性味道厌恶是否适用于气味。它还将检查是否需要先前的气味-味觉对经验来进行泛化，以及泛化的特异性是否遵循这种习得的味道-气味质量一致性。另一项单独的研究将调查味道体验--味道对气味厌恶的增强和气味对味道厌恶的增强的依赖。为了确定嗅球中是否发生了多感觉整合，第三项研究将评估口腔刺激是否以及如何调节清醒和急性大鼠的光学成像嗅球的气味反应。通过调制风味体验建立的刺激质量一致性和风味整合的时间一致性的重要性也将被评估。总而言之，这些研究旨在利用大鼠模型从根本上提供关于味道感知神经机制的新知识。与公共健康相关：这个项目调查了味觉的神经基础。由于味道在刺激食物摄入方面起着核心作用，因此研究味道感知的神经机制对于了解导致肥胖、糖尿病和心血管疾病等与饮食相关的疾病的感觉因素是至关重要的。

Description (provided by applicant): How multimodal stimuli become integrated is a fundamental question in neuroscience. This question is particularly relevant to flavor perception, in which simultaneous stimulation of touch, temperature, taste and olfaction invariably occurs during ingestion. Functional imaging studies in humans have provided important insights into the neural bases of multimodal flavor integration, yet cannot address issues requiring higher resolution or experimental manipulation of neural activity or of flavor experience. To address these limitations, the goal of the present project is to establish a rat model for investigating the neural mechanisms of flavor integration. To determine whether retronasal olfaction occurs in rats as it does in humans, a first study will employ optical calcium imaging to measure spatio-temporal patterns evoked in the olfactory bulb by various behaviors associated with the oral ingestion of odorants by awake rats. The perceptual similarities between retro- and orthonasal odorants will simultaneously be investigated. To determine whether flavor integration occurs perceptually in rats, a second study will investigate whether conditioned odor aversions generalize to tastants, and whether conditioned taste aversions generalize to odorants. It will also be examined whether prior odor-taste pair experience is necessary for generalization to occur and whether the specificity of the generalization follows this learned taste-odor quality congruence. A separate study will investigate the flavor experience-dependence of the potentiation of an odor aversion by taste and of a taste aversion by odor. To determine whether multi-sensory integration occurs in the olfactory bulb, the third study will evaluate whether and how oral stimuli can modulate odor responses in the optically-imaged olfactory bulb of awake and acute rats. The importance of both stimulus quality congruence, as established by modulating flavor experience, and temporal congruence for flavor integration will also be assessed. Together these studies are intended to provide fundamentally new knowledge about the neural mechanisms of flavor perception using a rat model. PUBLIC HEALTH RELEVANCE: This project investigates the neural basis of flavor perception. Because flavor plays a central role in motivating food intake, research on the neural mechanisms of flavor perception is essential for understanding the sensory factors that contribute to eating-related disorders such as obesity, diabetes and cardiovascular disease.