Emergent Behavior in a Dish: Discovery of Bi-directional Spiraling as a Population Phenomenon in C. elegans Enables In-Depth Dissection of Mechanisms Underlying Group Behaviors

项目摘要/摘要 当个体遵循关于如何与他人互动以及他们的 产生具有新属性或能力的集团实体的环境1、2.常见的例子包括学校 一群鱼、一群鸟和一群蚂蚁。在紧急行为中，个体往往同时 在处理来自环境的感官信号的同时与多个其他个体进行交流2.3.所有这些 信息被整合起来，以产生在整个群体中非常有凝聚力的行为反应。 尽管复杂的信息集成是人类处理世界的一个标志，但其机制 小组中潜在的交流一直很难通过实验来探索。我发现了第一个 线虫中紧急群体行为的例子，其中个体在不在的情况下协调运动 身体接触：在一个简单的环境提示下，数百人的种群将 同步执行向内双向螺旋，最终集中最初分散的 人口集中在一个中心点。这种行为发生在打开的盘子上放上盖子，里面装着足够的 在没有食物的情况下蠕虫的密度，依赖于完整的感觉系统。此外，我还有 演示了来自高密度人群的线索可以在共享的空域中感知到，以诱导 个体蠕虫的螺旋状行为，否则就不会表现出螺旋运动。因此，我建议C. 线虫使用不稳定的线索来测量种群密度，螺旋行为是由集中的 当盘子合上时，这是一个提示。然而，我也证明了线索的积累不足以 如果蠕虫之间的距离太大，则会导致螺旋上升，这表明相邻蠕虫之间的本地线索 也参与协调螺旋运动。在目标1中，我将阐明个体产生和感知的线索 为了促进线虫的紧急螺旋运动，包括来自于 附近的个体。在目标2中，我将利用线虫的易驯养性来询问大脑活动 会产生紧急的螺旋行为。线虫是透明的，个体的大脑活动可以 通过跟踪自由移动的蠕虫中的钙瞬变直接可视化。我将探讨这样一个假设： 神经网络减少了输入的噪声，以产生最大限度地协调 集体行动。这些发现加在一起将阐明前所未有的突发行为背后的原理 解决方案，使我们能够识别在其他系统中发生的类似过程或设计人工 表现出螺旋行为的系统。

Project Summary/Abstract Emergent behaviors arise when individuals follow rules about how to interact with one another and their environment to produce a group entity with new properties or abilities1,2. Common examples include a school of fish, a flock of birds, and a colony of ants. In an emergent behavior, individuals often simultaneously communicate with multiple other individuals while processing sensory cues from the environment2,3. All this information is integrated to produce a behavioral response that is remarkably cohesive across the group. Though complex information integration is a hallmark of how humans process the world, the mechanisms underlying communication in groups have been difficult to probe experimentally. I have discovered the first example of emergent group behavior in C. elegans in which individuals coordinate motion without being in physical contact: in response to a simple environmental cue, a population of several hundred individuals will synchronously perform an inward bidirectional spiral that eventually concentrates the initially dispersed population at a central point. The behavior occurs when a lid is placed on an open dish containing a sufficient density of worms in the absence of food and is dependent on intact sensory systems. Furthermore, I have demonstrated that a cue from a high density population can be sensed across a shared airspace to induce spiral-like behavior in individual worms that would not otherwise show spiral motion. I therefore propose that C. elegans uses a volatile cue to gauge population density, and spiraling behavior is triggered by concentration of this cue when the dish is closed. However, I also demonstrate that accumulation of a cue is not sufficient to induce spiraling if inter-worm distance is too great indicating that local cues between neighboring worms are also involved in coordinating spiraling. In Aim 1, I will elucidate the cues that individuals produce and perceive to facilitate emergent spiraling in C. elegans including both long-range density cues and short-range cues from nearby individuals. In Aim 2, I will take advantage of the tractability of C. elegans to ask how brain activity produces emergent spiraling behavior. C. elegans are transparent, and the brain activity of individuals can be directly visualized by following calcium transients in freely moving worms4. I will explore the hypothesis that neural networks reduce the noise of inputs to produce maximally coherent behavior across individuals in the collective. Together these findings will illuminate principles underlying emergent behavior at unprecedented resolution which may allow us to identify similar processes occurring in other systems or design artificial systems which exhibit spiral behavior.