Perceptual Coding and Modulation of Odor Objects in the Human Brain

描述（由申请人提供）：神经科学的一个中心目标是阐明大脑如何将感官输入转化为感知表征。奇怪的是，尽管气味刺激是目标导向行为的核心，包括进食、交配和母性结合（对人类和非人类物种都是如此），但人们对从空气中产生嗅觉感知的神经转化知之甚少。由于大多数气味是不同分子的复杂混合物，嗅觉系统的一个重要挑战是将这些部分重新组装成连贯的感知整体或“对象”，这些感知整体或“对象”在感知上锚定到环境中的原始来源。了解人类大脑如何编码，区分和分类嗅觉对象是我们实验室的一个关键研究重点。研究人类的一个优势是，他们可以说话，并提供他们的感官体验的评级，提供了一个非常容易处理的方式将大脑活动模式直接与感知联系起来。在这里提出的工作中，我们将利用我们目前在嗅觉心理物理学，功能性磁共振成像（fMRI）和基于模式的成像分析与新的方法，实验和计算方法，剖析气味感知处理的组成部分在行为和神经水平。通过有效地解构气味刺激或嗅觉系统，我们将能够获得独特的见解气味对象编码和识别的功能组织。具体的研究将探索人类大脑中对气味的有意识感知产生的地方，高阶区域如何有助于感知编码和分类，以及大脑是否能够获得行为上突出的食物气味的个体元素。补充研究将调查熟悉的作用，奖励学习，以及先前的信念水平对嗅觉和非嗅觉脑区的气味对象模式和连接的出现和调制。这些实验将为人类大脑如何克服识别气味物体的挑战带来新的理解，并将突出有助于支持气味感知的关键区域。此外，我们的研究结果应该有用地告知其他感觉系统的人类神经生物学，并应该贡献有价值的基本信息，可以帮助指导阿尔茨海默病和帕金森病患者未来诊断策略的发展，这与嗅觉感知缺陷在其早期阶段。

DESCRIPTION (provided by applicant): A central goal of neuroscience is to clarify how the brain transforms sensory inputs into perceptual representations. Curiously, even though odor stimuli are at the heart of goal-directed behavior, including feeding, mating, and maternal bonding (for both human and non-human species), very little is known about the neural transformations that create olfactory percepts out of airborne molecules. Because most odors are complex mixtures of different molecules, an important challenge of olfactory systems is to re-assemble these parts into coherent perceptual wholes, or "objects," that are perceptually anchored to their original sources in the environment. Understanding how the human brain encodes, discriminates, and categorizes olfactory objects is a key research focus in our lab. An advantage to studying humans is that they can talk and provide ratings of their sensory experiences, offering a highly tractable way to relate brain activity patterns directly to perception. In work proposed here, we will leverage our current strengths in olfactory psychophysics, functional magnetic resonance imaging (fMRI), and pattern-based imaging analysis with new methodological, experimental, and computational approaches to dissect the components of odor perceptual processing at the behavioral and neural levels. By effectively deconstructing either the odor stimulus or the olfactory system, we will be able to gain unique insights into the functional organization of odor object coding and recognition. Specific studies will explore where conscious perception of an odor arises in the human brain, how higher- order regions contribute to perceptual coding and categorization, and whether the brain has access to individual elements of a behaviorally salient food odor. Complementary studies will investigate the role of familiarity, reward learning, and levels of prior belief on the emergence and modulation of odor object patterns and connectivity in olfactory and non-olfactory brain areas. Together these experiments will bring novel understanding of how the human brain overcomes the challenges of recognizing odor objects, and will highlight the key regions that are instrumental in supporting odor perception. In addition, our findings should usefully inform the human neurobiology of the other sensory systems, and should contribute valuable basic information that could help guide development of future diagnostic strategies in patients with Alzheimer's disease and Parkinson's disease, which are associated with olfactory perceptual deficits in their earliest stages.