Multisensory mechanisms underlying flavor preference formation

摘要 任何患过普通感冒的人都知道，味觉和嗅觉都有助于我们体验到 食物。了解气味和味道如何相互作用最终驱动食物选择将对我们的 了解以异常食物选择为典型特征的疾病，最明显的是肥胖和 糖尿病。然而，味觉-嗅觉相互作用的神经机制在很大程度上仍不清楚，而且 是本提案的重点。这项拟议的工作直接源于现有的行为和神经- 生理数据。行为研究表明，味觉对气味的影响在味道偏好中- 信息传递。我们实验室最近的工作已经确定了一种潜在的神经底物，用于调节 通过证明初级嗅觉皮质(OC)通过初级味觉接受味觉输入的嗅觉 皮质(GC)。以大鼠为模型系统，本方案将结合自然主义的多感官刺激 味觉偏好学习任务中的呈现、光遗传学和电生理记录 探讨初级味觉系统和嗅觉系统之间的相互作用在调节多发性嗅觉反应中的作用。 感官味道偏好学习。特定目标1将使用解剖示踪、光遗传操作GC OC中的神经元轴突终末，以及解剖系统和电路的电生理标测实验- 味觉输入到OC的层次组织。初步数据表明单突触投射的存在 从GC到OC。然后，特定目标2将记录单个OC神经元的活动，以响应单一和多个 感官味道刺激，以表征与味道相关的味觉和嗅觉输入的汇聚和整合。 初步数据表明，OC的味觉和嗅觉输入是通过功能、空间和时间整合的 汇聚在单个OC神经元上。具体目标3将把味觉输入转发到OC的网络放在 味觉介导的味道偏好学习任务的背景以确定GCOC预测的因果作用 调整气味表现形式，形成口味偏好。初步数据表明，多感官前- 周围环境会导致OC气味反应的持久变化。这些实验所获得的结果将有助于进一步研究。 通过对OC如何在自然的、与行为相关的多感官环境中发挥作用的新见解，特别是 揭示味觉-嗅觉相互作用在味道感知和偏好形成中的潜在机制。

SUMMARY Anyone who has ever suffered a common cold knows that both taste and smell contribute to our experience of food. Understanding how smell and taste interact to ultimately drive food choice will make a major impact on our understanding of disorders that are typically characterized by abnormal food choice, most notably obesity and diabetes. The neural mechanisms underlying taste-smell interactions, however, remain largely unknown, and are the focus of the present proposal. The proposed work follows directly from existing behavioral and neuro- physiological data. Behavioral work has demonstrated an influence of taste on smell in flavor preference for- mation. Recent work from our own lab has identified a potential neural substrate for mediating the influence of taste on smell by demonstrating that primary olfactory cortex (OC) receives gustatory input via primary gustatory cortex (GC). Using rats as a model system, the present proposal will combine naturalistic multisensory stimulus presentation, optogenetics and electrophysiological recordings in the context of a flavor preference learning task to investigate the role of interactions between the primary gustatory and olfactory systems in mediating multi- sensory flavor preference learning. Specific Aim 1 will use anatomical tracing, optogenetic manipulation of GC neuron axon terminals in OC, and electrophysiological mapping experiments to dissect the systems- and circuit- level organization of gustatory input to OC. Preliminary data suggest the existence of monosynaptic projections from GC to OC. Specific Aim 2 will then record activity from single OC neurons in response to uni- and multi- sensory flavor stimuli to characterize convergence and integration of flavor-related gustatory and olfactory input. Preliminary data suggest that taste and smell inputs to OC are integrated through functional, spatial and temporal convergence on single OC neurons. Specific Aim 3 will place the network relaying gustatory input to OC in the context of a taste-mediated flavor preference learning task to determine the causal role GCOC projections in modulating odor representations and forming flavor preferences. Preliminary data suggest that multisensory ex- perience induces lasting changes in OC odor responses. The results obtained from these experiments will pro- vide novel insight into how OC functions in a natural, behaviorally-relevant multisensory context, specifically uncovering the mechanisms underlying taste-smell interactions in flavor perception and preference formation.