The assembly of population coding networks

项目摘要 群体编码是神经系统表征感觉刺激的基本策略 and generate生成perception感知.在执行群体编码（称为“群体编码”）的神经网络中， 神经网络（PCNs）”），输入引起的反应在神经元之间是定量异质的， 单个神经元的响应不足以定义刺激;相反， 整个神经元群体是刺激感知的基础。尽管多氯化萘很重要， 人们对它们在发育过程中是如何组装的知之甚少。拟议研究的目标 是确定在开发过程中建立PCN的机制。在许多多氯化萘中， 神经元彼此之间除了通过它们不同的生理特性之外是无法区分的。 虽然这些PCNs的明显同质性确保了组成神经元对相同的神经元的贡献。 脑功能，它也提出了一个挑战，研究分子和细胞机制， 多氯化萘的组装。最近的一项研究报告了一种神经网络，它编码有害物质的强度， 通过果蝇幼虫群体编码输入，这为研究PCN提供了一个很好的系统 组装件.初步结果表明，Hox基因参与建立这种PCN。中央 一个假设是，有丝分裂后的Hox代码指定了沿A-P沿着不同神经元的突触输入 轴，建立一个人口编码网络，编码刺激强度。这一假设将是 通过确定建立异质性的细胞（目标1）和分子（目标2）机制进行测试 这个PCN中的神经元。这项研究是创新的，因为它提出了新的细胞和 在神经网络中产生定量异质性的分子机制。此外，它将使用一个 新开发的技术，非常适合研究在PCN神经元群体活动。小说 还开发了遗传工具用于访问PCN中的神经元亚群。本研究 是重要的，因为它将提供细胞，分子和概念的见解，建立 果蝇和其他物种中的其他多氯化萘。除了多氯化萘，它还将告知生理学 异质性出现在看似相同的神经元组中。此外，成功完成 这项研究还将展示一种基于Hox的匹配系统， 连接局限于特定的吻尾节。

PROJECT SUMMARY Population coding is a fundamental strategy that the nervous system employs to represent sensory stimulus and generate perception. In neural networks that perform population coding (termed “population coding networks (PCNs)”), input-elicited responses are quantitatively heterogeneous across neurons and the response of a single neuron does not sufficiently define the stimulus; instead, the computed response of the entire population of neurons underlies the perception of the stimulus. Despite the importance of PCNs, very little is known about how they are assembled during development. The objective of the proposed research is to identify the mechanisms that establish a PCN during development. In many PCNs, the constituent neurons are not distinguishable from each other, except by their heterogeneous physiological properties. While the apparent homogeneity of these PCNs ensures that constituent neurons contribute to the same brain function, it also poses a challenge for studying the molecular and cellular mechanisms that underlie the assembly of PCNs. A recent study reported a neural network that encodes the intensity of noxious inputs through population coding in Drosophila larvae, which offers an excellent system for studying PCN assembly. Preliminary results suggest that Hox genes are involved in establishing this PCN. The central hypothesis is that a post-mitotic Hox code specifies the synaptic inputs to different neurons along the A-P axis, establishing a population-coding network that encodes stimulus intensity. This hypothesis will be tested by identifying the cellular (Aim 1) and molecular (Aim 2) mechanisms that establish the heterogeneity of the neurons in this PCN. The proposed research is innovative because it proposes novel cellular and molecular mechanisms that generate quantitative heterogeneity in a neural network. Moreover, it will use a newly developed technique that is ideally suited for studying neuronal population activity in the PCN. Novel genetic tools have also been developed for accessing subpopulation of neurons in the PCN. This research is significant because it will provide cellular, molecular, and conceptual insights into the establishment of other PCNs in Drosophila and other species. Beyond the PCNs, it will inform how physiological heterogeneity arises in a seemingly identical group of neurons. Furthermore, the successful completion of the proposed study will also demonstrate a Hox-based matching system that establish neuronal connections confined to specific rostrocaudal segments.