Mammalian behavioral discrimination and neural processing of naturalistic odor plumes based on intermittency

项目摘要 哺乳动物利用气味导航来避免有害的环境危险，寻找食物来源，定位配偶， 逃避捕食者--生存的关键行为。自然界中的气味通常由湍流气流携带， 具有复杂时空结构的气味羽流。间歇性是一种流体动力学参数， 这种波动的性质作为时间的一部分气味存在于烟缕内的一点处。间歇性减少 与气味源的距离增加，并且可以提供关于源接近度的重要信息。 这些气味信息必须由动物采样，由嗅觉系统整合，并最终驱动 导航哺乳动物通过嗅闻来调节气味采样，快速采样可能会支持 在羽流的低不透明度部分检测稀疏气味。此外，嗅觉神经元 （OSN）能够具有快速响应特性，其有益于检测短暂的气味呈现， 以及对持续气味呈现的反应适应 景观虽然动态气味羽流在自然界中普遍存在，但大多数研究都集中在嗅觉上， 处理静态气味。这个提议的目的是检查小鼠是否可以使用 气味羽流导航，并确定他们的神经行为反应，这些动态气味序列。 这项提议将检验一个假设，即老鼠可以利用嗅觉来导航气味羽流， 嗅闻和OSN响应特性的调制使得能够检测烟羽外围的气味存在 以及靠近源的气味环境的变化。在初步工作中，小鼠被训练完成一项任务， 他们区分气味序列，有些直接从气味羽流中取样，使用 不稳定性。他们用来执行这项任务的采样策略被假设为嗅闻的增加 频率在气味呈现期间在低湿度下检测稀疏气味。这将是决定 通过测量任务期间的嗅探频率。此外，OSN响应将被量化以检验假设 在低浓度下，需要对每种气味气味的强烈反应来进行气味辨别（Aim 1）。为了定义OSN响应对波动气味的适应，OSN响应幅度减小到 在表现出一定范围的嗅闻的小鼠中， 频率（目标2）。如果导航依赖于可靠的检测气味存在的周边和变化 在接近源的气味环境中，OSN对低重复性刺激的反应可能是敏感的， 许多抖动和适应可能仅在高重复性刺激下发生。该提案将深入了解 哺乳动物如何解释嗅觉信息以定位基本气味源。这项工作与 NIDCD的使命是了解嗅觉的正常过程，因为它对无数的日常功能至关重要。

PROJECT SUMMARY Mammals use odor navigation to avoid noxious environmental dangers, find food sources, locate mates, and escape predators- critical behaviors for survival. Odors in nature are often carried by turbulent air flow, producing odor plumes with complex spatiotemporal structure. Intermittency is a fluid dynamics parameter that quantifies this fluctuating nature as the fraction of time odor is present at a point within the plume. Intermittency decreases with increased distance from an odor source and may provide important information about source proximity. Such odor information must be sampled by animals, integrated by the olfactory system, and ultimately, drive navigation. Mammals modulate odor sampling through sniffing, and rapid sampling can possibly support the detection of sparse odor whiffs at low intermittency sections of a plume. In addition, olfactory sensory neurons (OSNs) are capable of rapid response properties that are beneficial for detection of fleeting odor presentation as well as response adaptation to persistent odor presentation that allows for detection of changes in the odor landscape. Although dynamic odor plumes are prevalent in nature, most studies have focused on olfactory processing of static odors. The objective of this proposal is to examine if mice can use temporal properties of odor plumes for navigation and to determine their neurobehavioral responses to these dynamic odor sequences. This proposal will test the hypothesis that mice can use intermittency to navigate odor plumes and that modulation of sniffing and OSN response properties enable detection of odor presence at the plume periphery and changes in the odor environment close to the source. In preliminary work, mice were trained on a task in which they discriminate between odor sequences, some directly sampled from an odor plume, using intermittency. The sampling strategies they use to perform this task are hypothesized as an increase in sniff frequency during odor presentation at low intermittencies to detect sparse odor whiffs. This will be determined by measuring sniff frequency during the task. Moreover, OSN responses will be quantified to test the hypothesis that at low intermittencies, robust responses to each odor whiff are needed for intermittency discrimination (Aim 1). To define OSN response adaptation to fluctuating odors, decreases in OSN response amplitude to consecutive odor whiffs across increasing intermittency will be quantified in mice displaying a range of sniff frequencies (Aim 2). If navigation depends on reliable detection of odor presence at the periphery and changes in odor environment close to the source, OSN response to low intermittency stimuli may be sensitive across many whiffs and adaptation may only occur with high intermittency stimuli. This proposal will provide insight into how mammals interpret olfactory information to localize essential odor sources. This work is well-aligned with the NIDCD mission to understand the normal processes of smell as it is critical to countless everyday functions.