Perceptual Coding and Modulation of Odor Objects in the Human Brain

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知觉。 申述。奇怪的是，尽管气味刺激是目标导向行为的核心，包括 关于喂食、交配和母体结合(对于人类和非人类物种)，人们对 从空气中的分子产生嗅觉的神经转化。因为大多数气味都是 不同分子的复杂混合物，嗅觉系统的一个重要挑战是重新组装这些 部分形成连贯的感知整体，或“对象”，它们在感知上锚定在它们的原始来源上 环境。了解人脑如何编码、辨别和分类嗅觉 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可以说话并提供 对他们的感觉体验进行评级，提供了一种非常容易处理的方式，将大脑活动模式直接与 感知力。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)，以及采用新方法的基于模式的成像分析， 实验和计算方法，以剖析气味感知处理的组件在 行为和神经层面。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发生在哪里，如何更高的级别 区域有助于知觉编码和分类，以及大脑是否可以访问 行为上突出的食物气味的个别元素。补充性研究将调查 对气味客体模式的出现和调节的熟悉度、奖励学习和先前信念水平 以及嗅觉和非嗅觉脑区的连接。这些实验加在一起将带来新的 了解人脑如何克服识别气味物体的挑战，并将强调 支持气味感知的关键区域。此外，我们的发现应该是有益的 告知人类其他感觉系统的神经生物学，并应提供有价值的基本信息 这有助于指导阿尔茨海默病患者未来诊断策略的发展 帕金森氏症，这与早期的嗅觉缺陷有关。

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 higherorder 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.