The basis of fructose sensation: Instructions provided by the peripheral nervous system to select appropriate behavioral actions

味觉刺激有助于动物在其环境中寻找能量丰富的食物来源，以维持生存，并避免不愉快或有毒的底物。糖通常预示着营养价值，被认为是有吸引力和有益的。因此，富含糖的食物来源会引发一系列行为，包括吸引、食物选择和消费——这些行为对所有动物来说都是基本的。例如，像果蝇这样的昆虫会被大多数人类也喜欢的糖所吸引。果蝇检测、评估和消耗糖的复杂机制对其幼虫（动物的进食阶段）特别重要。这一时期的生命周期只有5天左右，在此期间，动物的体重增加了几百倍。它们从大约10微克的微小的一龄幼虫生长到重约2毫克的徘徊的三龄幼虫。已知在这段快速生长时期起关键作用的主要营养物质除了氨基酸外还有糖。为了有效地检测这些物质，幼虫利用一个简单但有效的数字周围神经系统。因此，在这个项目中，我们将分析周围神经系统如何感知和处理来自环境的果糖刺激，从而在正确的时间选择适当的行动。利用最近建立的连接组，可用的第二代分裂- gal4工具，新建立的幼虫标准脑图谱（www.larvalbrain.org），以及以高速和分辨率监测和评估幼虫行为的成熟分析（FIM跟踪），我们将分析三种不同的果糖相关行为：果糖偏好（在哪里喂食），果糖摄入（喂食什么）和果糖增强嗅觉学习（何时喂食）。我们的目标是提供一个简单的数字和功能可接近的幼虫外周感觉系统如何指导食物相关的行动选择的答案。这是每个动物为了生存都必须解决的任务。

Gustatory stimuli are instrumental for an animal to sample its environment for energy-rich food sources to maintain survival, and to avoid unpleasant or poisonous substrates. Sugars often predict a nutritional benefit and are perceived as attractive and rewarding. Therefore, sugar-rich food sources trigger a series of behaviors including attraction, food selection, and consumption - actions that are fundamental for all animals. Insects for example - like Drosophila - are attracted to most sugars that are also preferred by humans.Sophisticated mechanisms that allow Drosophila to detect, evaluate, and consume sugars are of special importance for its larva – the feeding stage of the animal. This period of the life cycle is restricted to only about 5 days, during which the animal increases its weight up to several hundred-fold. They grow from a tiny first-instar larva of about 10 μg to a wandering third-instar larva weighing about 2 mg. The main nutrients known to be critical for this period of rapid growth are sugars besides amino acids. To efficiently detect these substances, the larva utilizes a numerical simple but efficient peripheral nervous system.Accordingly, in this project we will analyze how the peripheral nervous system perceives and processes fructose stimuli from its environment to select the appropriate action at the right time. Using the recently established connectome, available second-generation split-Gal4 tools, a newly established larval standard brain atlas (www.larvalbrain.org), and well established assays that monitor and evaluate larval behavior at high speed and resolution (FIM tracking), we will analyze three different fructose-related behaviors: fructose preference (where to feed), fructose ingestion (what to feed) and fructose reinforced olfactory learning (when to feed). We aim to provide an answer on how the numerically simple and functional accessible larval peripheral sensory system instructs food-related action selection. A task that every animal has to solve in order to survive.