STRUCTURE AND PHYSIOLOGY OF PREMOTOR LOCAL INTERNEURONS

其目标是了解模式产生电路中的神经元是如何 发挥作用，并有助于有序的行动。局部中间神经元是 大脑中最丰富的神经元，但因为它们很小，很难 要记录下来，人们对它们的生理特征知之甚少。一个 已发现少量无轴突、无棘波的局部中间神经元。 小龙虾是产生节奏的神经回路的一部分 游泳动作。这些中间神经元是可识别的，并且足够大 为了允许实验探索它们的生理特性和 突触相互作用。我们提出了三个项目，描述如何 这些非尖峰的局部中间神经元参与了游泳者的节奏。 为了测试这些中间神经元在产生游泳网中的作用 运动时，单个中间神经元会受到干扰或消融，而 神经系统正在产生游泳者的节奏。的膜 中间神经元将被夹在不同的电位上 单电极电压钳位控制变送器的释放。 单个中间神经元将通过光灭活来消融。比较 在电压钳位之前和期间产生的电机模式或 消融前和消融后将揭示这些因素的贡献 在它们自己的回路和整个运动模式中的中间神经元 动物。 为了检验非刺激性局部中间神经元是运动前驱的假设，以及 生理上远离感官输入，成对识别的 运动神经元、感觉神经元和中间神经元将被注射 路西法黄色和HRP，然后研究描述和计算他们的分数 联系的方式。表观接触区域将被薄切，以便EM到 找到任何突触。 为了分析这些中间神经元如何整合突触电流，我们将 详细地描述它们的无源电气结构 脉冲响应和阶跃响应测量相结合的模型 仔细测量它们的解剖结构。这些预测 该模型将用单电极电压钳进行测试，以 测量已知来源的突触电流和突触电位。这 分析将检验以下假设：突触整合的“亚单位” 存在于这些树枝状结构中。

The goal is to understand how neurons in pattern-generating circuits function and contribute to orderly movements. Local interneurons are the most abundant neurons in brains, but because they are small and difficult to record, little is known about their physiological characteristics. A small set of axonless, nonspiking local interneurons has been discovered in the crayfish that is part of the neural circuits that generate rhythmic swimming movements. These interneurons are identifiable, and large enough to permit experiments that explore their physiological properties and synaptic interactions. We propose three projects that will describe how these nonspiking local interneurons contribute to the swimmeret rhythm. To test the role of these interneurons in generating the swimmeret movements, individual interneurons will be perturbed or ablated while the nervous system is generating the swimmeret rhythm. The membranes of interneurons will be clamped to different potentials with a single-electrode voltage clamp to control their release of transmitter. Individual interneurons will be ablated by photoinactivation. Comparisons of the motor patterns generated before and during the voltage clamp or before and after ablation will reveal the contribution of these interneurons to the motor pattern in their own circuit and in the whole animal. To test the hypothesis that nonspiking local interneurons are premotor, and physiologically remote from sensory input, pairs of identified motorneurons, sensory neurons and interneurons will be injected with Lucifer yellow and HRP and then studied to describe and count their points of contact. Regions of apparent contact will be thin-sectioned for EM to locate any synapses. To analyze how these interneurons integrate synaptic currents, we will describe their passive electrical structure in a detailed compartmental model by combining measurements of their pulse-responses and step-responses with careful measurements of their anatomical structure. The predictions of this model will be tested with a single-electrode voltage clamp to measure synaptic currents and synaptic potentials from known sources. This analysis will test the hypothesis that "subunits" of synaptic integration exist in these dendritic structures.