ANALYSIS OF INTERNEURONS AND MOTOR NEURONS

该项目的长期目标是了解如何紧张 系统控制运动。 躯体运动神经元通常用于更多的 可以在各种空间和时间中被激活 模式. 一般来说，运动神经元是由一群前运动神经元驱动的。 中间神经元 前运动中间神经元如何组织和激活， 产生不同的运动模式 是构成图案的神经元 一种发电机的一种行为涉及到另一种电动机的发电 回应？ 如果是这样，一组神经元通过什么机制 一起服务于一种运动功能，重组以参与另一种运动功能， 运动模式 为了解决这些问题，我们将集中讨论 中枢神经系统内的中间神经元和运动神经元的组织 软体动物Tritonia diomedea作为模式系统。 我们的实验方法 分为三个方面。 利用细胞内记录， 识别的前运动中间神经元和运动神经元的模式将被 在三种不同的行为中定量表征：游泳， 反射性退缩和进食 这些行为中的每一个都涉及一个 运动神经元的共同池以三种不同的模式激活。 一 第二个系列的实验集中在细胞和突触机制 并且包括i）突触的网络分析， 中间神经元之间的连接和整合特性， 运动神经元，ii）分析该运动系统的感觉输入通路， 和（iii）确定运动网络内的调节位点。 最后重建中间神经元和运动神经元网络 通过数字计算机模拟来提供对相互作用的见解， 细胞和突触特性在产生多个， 复杂的运动模式 这些实验应该揭示 运动系统的组织将适用于更复杂的系统 其中这种水平的细胞分析是不可能的。

The long term goal of the proposed project is to understand how nervous systems control movement. Somatic motor neurons are commonly used in more than one movement and can be activated in a variety of spatial and temporal patterns. In general, motor neurons are driven by a population of premotor interneurons. How are the premotor interneurons organized and activated to yield different motor patterns? Are the neurons which comprise the pattern generator for one behavior involved in the generation of other motor responses? If so, by what mechanisms can a set of neurons connected together to subserve one motor function be reorganized to participate other motor patterns? To address these questions we will concentrate on the organization of interneurons and motor neurons within the CNS of the mollusc, Tritonia diomedea, as a model system. Our experimental approach is divided into three areas. Using intracellular recordings, the firing patterns of identified premotor interneurons and motor neurons will be characterized quantitatively during three different behaviors: swimming, reflexive withdrawals, and feeding. Each of these behaviors involves a common pool of motor neurons activated in three different patterns. A second series of experiments focuses on cellular and synaptic mechanisms for pattern generation and includes i) a network analysis of the synaptic connectivity between and integrative properties of the interneurons and motor neurons, ii) analysis of sensory input pathways to this motor system, and (iii) identification of modulatory sites within the motor network. Finally the network of interneurons and motor neurons will be reconstructed by digital computer simulation to provide insights into the interaction and role of cellular and synaptic properties in the generation of multiple, complex motor patterns. These experiments should uncover principles of motor system organization which will be applicable to more complex systems in which this level of cellular analysis is not possible.