Mechanisms of chemosensory behavioral plasticity in C. elegans

所有动物都能感知环境中的多种化学物质并做出反应。化学线索表明食物、配偶、捕食者和有毒物质的存在，动物对不同的气味有吸引、排斥或无动于衷的反应。然而，动物对化学物质的反应不是固定的，而是可以被它们过去的经历和现在的状态所改变。例如，长时间暴露在气味中会降低随后对该化学物质的反应，而且幼鱼和成年鱼对化学物质的反应不同。这种灵活性确保动物表现出最适合其当前条件的行为。该项目的总体目标是探索动物的经历及其发育阶段如何改变神经系统的功能，从而驱动不同的化学感知行为。鉴于嗅觉和味觉在动物生命周期中的重要性，这项工作使我们能够开始探索环境变化如何影响动物福利，并有助于畜牧业和保护工作。拟议的工作将支持对高中生、本科生和研究生以及博士后的培训，并将尽一切努力让代表性不足的少数群体成员参与进来。该项目还建立了大学实验室与高中学生和教师之间的研究关系。这项工作的真知灼见，透过在本地科学博物馆和科学展览的亲身示范，与公众分享。拟议的工作还包括生物学家、化学家和生物工程师之间的合作，因此有望促进跨学科的学习和创新。先天行为和习得行为都是灵活的，并且受到动物的经验以及外部和内部状态的广泛调节。本提案的具体目标是鉴定和表征在线虫化学感觉行为反应中介导环境和发育阶段特异性可塑性的分子、神经元和电路。初步实验表明，情境线索调节了对抗性神经回路的输出，使人们对简单的酒精的反应在吸引和厌恶之间切换。行为策略和这种反应灵活性背后的神经元机制是通过在特定条件下对行为状态和神经元活动的高分辨率分析来表征的。秀丽隐杆线虫的化学感觉行为也受到发育阶段和环境经验的显著调节。提出的研究表征了这种依赖于经验和阶段的化学感觉行为可塑性，并确定了所需的神经元和分子机制。这项工作的结果为动物有效改变其行为以应对不断变化的外部和内部条件的机制提供了新的信息。

All animals sense and respond to multiple chemicals in their environment. Chemical cues signal the presence of food, mates, predators, and toxic substances, and animals are attracted, repelled, or indifferent to individual odors. However, the responses of animals to chemicals are not fixed, but can be altered by their past experience and current state. For example, prolonged prior exposure to an odor decreases subsequent responses to that chemical, and juveniles and adults can exhibit different responses to chemicals. This flexibility ensures that the animal exhibits the behavior that is most appropriate for its current condition. The overall goal of this project is to explore how an animal's experience and its developmental stage alter the functions of the nervous system to drive different chemical-sensing behaviors. Given the importance of smell and taste in animal lifecycles, this work allows us to begin to explore how changes in the environment may impact animal welfare, and aid in animal husbandry and conservation efforts. The proposed work supports the training of high school, undergraduate and graduate students, and postdoctoral fellows, and all efforts will be made to involve members of underrepresented minority groups. The project also builds research relationships between university labs and high school students and teachers. The insights from this work are shared with the public via hands-on demonstrations at local science museums and science fairs. The proposed work also incorporates collaborations among biologists, chemists and bioengineers, and is thus expected to promote interdisciplinary learning and innovation.Both innate and learned behaviors are flexible, and are extensively modulated by an animal's experience as well as its external and internal state. The specific goal of this proposal is to identify and characterize the molecules, neurons, and circuits that mediate context- and developmental stage-specific plasticity in chemosensory behavioral responses of the nematode C. elegans. Preliminary experiments suggest that contextual cues modulate the output of antagonistic neural circuits to toggle the response to a simple alcohol between attraction and aversion. The behavioral strategies and neuronal mechanisms underlying this response flexibility is characterized using high-resolution analyses of behavioral states and neuronal activity under defined conditions. C. elegans chemosensory behaviors are also dramatically modulated as a function of developmental stage and environmental experience. The proposed research characterizes this experience- and stage-dependent chemosensory behavioral plasticity, and identifies the required neuronal and molecular mechanisms. Results from this work provide new information about the mechanisms by which animals efficiently alter their behaviors in response to changing external and internal conditions.