CRCNS: From Sensation to Perception: Cellular and Circuit Mechanisms Underlying Prey Detection in an Electric Fish

神经科学的一个主要目标是了解大脑的许多组成部分如何相互作用，从而产生人类和其他动物所表现出的非凡的感知、运动和思考能力。对于大多数大脑区域来说，部件列表太长，功能知之甚少。这个提议利用了一种不寻常的动物——一种能发出自己电场的鱼——它的大脑结构非常简单，功能也很好理解，因此神经回路的详细结构可以直接与功能联系起来。该项目结合了对鱼大脑各个组成部分的高分辨率实验测量和数学建模来建立这种联系。该提案的具体目标是了解神经元之间连接强度的变化如何使鱼类学会忽略自身运动动作产生的感觉，从而更好地感知昆虫猎物产生的微小电场。这项工作需要实验者和神经建模者之间广泛的合作交流，并将为本科生和研究生提供跨学科的培训。此外，科学项目将被开发并带到市中心的K-12教室。最后，这项工作对我们理解学习区分自我产生和外部感觉信号的神经机制的失败有意义，这一问题被认为发生在人类神经系统疾病中，如精神分裂症。电鱼的小脑样电感觉叶（ELL）是研究运动必然放电如何用于预测自生感觉信号的理想模型系统。过去的工作已经产生了一个经过充分验证的模型，在这个模型中，脉冲时间依赖的突触可塑性将描述良好的运动必然放电反应雕刻成对鱼自身电器官放电（EOD）的感觉反应的负面图像。本提案的目标是将该模型从对ELL中负图像记录的描述扩展到对鱼类使用该电路检测猎物产生的微小电信号的能力的理解。该项目将确定ELL如何支持检测猎物样信号，这些信号来自于在ELL内的几个关键处理阶段记录的已识别神经元类别的细胞外尖峰序列。与此同时，将构建ELL自适应处理模型，以确定在神经和行为水平上测量检测性能所需的基本特征。总之，这些密切协调的实验和理论努力将提供详细的解释，可塑性如何在一个特征良好的电路中运作，有助于行为。

A primary goal of neuroscience is to understand how the many components of the brain interact with each other to give rise to the remarkable capacities of perception, movement, and thinking exhibited by humans and other animals. For most brain regions, the parts list is too long and the function is poorly understood. This proposal takes advantage of an unusual animal--a fish that emits its own electrical field-- in which the brain structure is simple enough and the function sufficiently well understood, so that the detailed structure of neural circuits can be directly linked to function. The project combines high-resolution experimental measurements from individual components of the fish's brain with mathematical modeling to make such links. The specific goal of the proposal is to understand how changes in the strength of connections between neurons allows the fish to learn to ignore sensations produced by its own motor actions, so that the fish is better able to perceive tiny electrical fields generated by insect prey. The work entails extensive collaborative exchange between experimentalists and neural modelers, and will provide students at the undergraduate and graduate level with cross-disciplinary training. Additionally, science projects will be developed and taken to inner-city K-12 classrooms. Finally, the work has implications for our understanding of failures in the neural mechanisms that learn to distinguish self-generated from external sensory signals, a problem that is thought to occur in human neurological disorders such as schizophrenia.The cerebellum-like electrosensory lobe (ELL) of mormyrid electric fish is an ideal model system for exploring how motor corollary discharge is used to predict self-generated sensory signals. Past work has produced a well-tested model in which spike timing-dependent synaptic plasticity sculpts well-described motor corollary discharge responses into a negative image of the sensory response to the fish's own electric organ discharge (EOD). The goal of this proposal is to extend this model from a description of the recordings of negative images in ELL to an understanding of the fish's ability to use this circuitry to detect the minute electrical signals generated by prey. The project will determine how ELL supports the detection of prey-like signals assessed from extracellular spike trains of identified neuron classes recorded at several key processing stages within the ELL. In parallel, models of ELL adaptive processing will be constructed to identify the essential features needed to account for the measured detection performance at both the neural and the behavioral level. Together, these closely coordinated experimental and theoretical efforts will provide a detailed explanation of how plasticity operating in a well-characterized circuit contributes to behavior.