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觉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，包括喂养、交配和母性关系（对人类和非人类物种都是如此），但人们对空气中分子产生嗅觉感知的神经转换知之甚少。因为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合成连贯的感知整体，或“物体”，这些物体在感知上固定在环境中的原始来源上。了解人类大脑如何编码、区分和分类嗅觉物体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，他们会说话，并对自己的感官体验进行评级，这提供了一种非常容易处理的方法，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，我们将利用我们在嗅觉心理物理学、功能磁共振成像（fMRI）和基于模式的成像分析方面的现有优势，采用新的方法、实验和计算方法，在行为和神经水平上剖析气味感知加工的组成部分。通过有效地解构气味刺激或嗅觉系统，我们将能够对气味对象编码和识别的功能组织获得独特的见解。具体的研究将探索人类大脑中对气味的有意识感知，高阶区域如何促进感知编码和分类，以及大脑是否可以访问行为显著的食物气味的单个元素。补充研究将探讨熟悉度、奖励学习和先验信念水平在嗅觉和非嗅觉脑区的气味对象模式和连接的出现和调节中的作用。总之，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，并将突出在支持气味感知方面起重要作用的关键区域。此外，我们的研究结果将有助于了解其他感觉系统的人类神经生物学，并提供有价值的基础信息，有助于指导阿尔茨海默病和帕金森病患者未来诊断策略的发展，这两种疾病在早期阶段都与嗅觉知觉缺陷有关。

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.