The neural circuitry of learning, memory, and decision-making in honey bees

西方蜜蜂(意大利蜜蜂)以其复杂的行为而闻名。它可以学习一天中食物可获得的时间和多个同时食物来源的可获得位置。它可以记忆和计算地标，并跟随天空中的紫外线模式(太阳指南针)导航到已知的食物来源。然后，它可以回到家，通过一种被称为“摇摆舞”的象征性语言，将食物来源的位置传达给它的蜂群。在这种语言中，食物来源的方向和距离是通过身体动作来传达的。人类利用蜜蜂获取蜂蜜和蜂蜡已有9000年的历史，而在这一半的时间里，人类积极地饲养驯化的蜜蜂。然而，即使是亚里士多德也以饲养蜜蜂而闻名，但仔细的蜜蜂实验直到18世纪才开始。即使是现在，我们也只是刚刚开始了解任何动物行为的神经基础。神经行为学是从进化和比较的角度研究大脑结构和功能的学科。它主要关注大脑如何产生行为。因为蜜蜂的大脑对于昆虫来说非常大，大约有1mm3，包含近100万个神经元，而且蜜蜂拥有如此令人印象深刻的复杂行为，蜜蜂是神经行为学的理想研究动物。发现蜜蜂大脑如何产生行为是我研究计划的长期目标。在这个资助周期中，我的实验室将继续探索一个重要的昆虫大脑区域的组织，称为蘑菇体(MB)，它涉及感觉整合、学习和记忆。我们将训练蜜蜂执行复杂的感觉学习任务，并观察这些信息在大脑中是如何编码的。我们还将观察大脑如何因这些经历而发生变化。有有限的证据表明，学习既发生在甲基溴的输入区(花萼)，也发生在甲基溴的输出区(脑叶)。我们最终将了解这些信息是如何组合在一起的，并与大脑中的其他信息流进行比较，以了解决策是如何做出的。这项工作之所以重要，有两个原因。首先，虽然昆虫的大脑不同于人类的大脑，但在很大程度上，神经元就是神经元。了解一个更容易控制的大脑的结构和功能将指导我们试图了解人类的大脑结构和功能(以及功能的丧失)。其次，传粉者的健康目前在世界范围内受到严重关注。随着栖息地的丧失，杀虫剂使用量的增加，以及新的入侵害虫，传粉者的数量几十年来一直在下降。仅蜜蜂授粉在加拿大就是一个价值25亿美元的行业，在全球范围内是一个价值2000亿美元的行业。考虑到传粉者约占我们食物的三分之一，解决昆虫的感觉整合、学习和决策问题至关重要，并可能导致生态系统服务的新工具，提高传粉者的效率，并可能增加作物产量。

The western honey bee (Apis mellifera) is renowned for its complex behaviour. It can learn the times of day of food availability and the locations of availability for multiple simultaneous food sources. It can memorize and count landmarks and follow UV light patterns in the sky (the "sun compass") to navigate to known food sources. It can then return home and communicate the locations of food sources to its hivemates via a symbolic language called the "waggle dance", wherein the direction and distance of the source are communicated by body movements. Humans have exploited bees for honey and wax for 9000 years and actively kept domesticated bees for half that time. However, while even Aristotle was known to keep bees, careful bee experimentation did not begin until the 18th century. Even now, we are only beginning to understand the neural underpinnings of behaviour in any animal. Neuroethology is the study of brain structure and function from an evolutionary and comparative perspective. It focuses largely on how brains produce behaviour. Because the honey bee has an unusually large brain for an insect, measuring about 1 mm3 and containing nearly 1 million neurons, and because the honey bee possesses such an impressive repertoire of complex behaviours, the honey bee is an ideal research animal in neuroethology. Discovering how honey bee brains produce behaviour is the long-term objective of my research program. In this grant cycle, my lab will continue to explore the organization of an important insect brain region called the mushroom bodies (MB), which are involved in sensory integration, learning, and memory. We will train bees to perform complicated sensory learning tasks and look at how this information is coded in the brain. We will also look at how the brain changes due to these experiences. There is limited evidence that learning occurs both in the MB input regions (the calyces) and the MB output regions (the lobes). We will ultimately learn how this information is combined and compared with other information streams in the brain to understand how decisions are made. This work is important for two reasons. First, while insect brains are different than human brains, to a large extent a neuron is a neuron. Understanding structure and function in a more tractable brain will guide us as we try to understand brain structure and function (and loss of function) in humans. Second, pollinator health is of serious concern worldwide right now. With loss of habitat, increased pesticide use, and new invasive pests, pollinator numbers have been declining for decades. Honey bee pollination alone is a $2.5 billion industry in Canada and a $200 billion industry worldwide. Considering pollinators are responsible for about a third of our food, solving problems in sensory integration, learning, and decision making in insects is critical and may lead to novel tools in ecosystem service, increasing pollinator efficiency, and possibly increasing crop yield.