OPTICAL STUDIES OF NEURON ACTIVITY AND ORGANIZATION

该项目的所有目标都涉及到光学方法的使用 用于监测神经元的活动。这些方法是基于这一发现 当某些染料结合到膜上时，会改变它们的光学性质 以响应膜电位的变化。 在无脊椎动物神经节中，光学监测检测到个体 单个细胞体的动作电位。使用124元素 位于显微镜图像平面上的光电二极管阵列我们已经能够 监测海兔或侧耳多个神经元的活动 颊神经节。我们认为我们正在接近监控能力 这类制剂中的大部分尖峰活动。这将提供一个 一种强大的工具，可以确定在特定情况下所有活跃的神经元 行为和检验关于简单的神经元控制的假说 行为。我们对SIMPLE的护理基础特别感兴趣 学习的形式。其他行为实验和光学 建议在半完整制剂中进行即刻测量 未来。紧随其后的是试图确定 神经元之间的相互作用发生了变化，以实现这一行为。 在脊椎动物的神经系统中，光学监测还没有单一的 单元格分辨率。这些信号代表细胞膜的平均变化 成像到个体上的神经元和突起的电位 探测器。目前，有可能测量大鼠活动的变化 感觉皮层对胡须运动或闪光的反应。我们计划 在这些实验中提高信噪比的实验，以 开发光学测量在猫视皮层中的应用，并 确定是否存在气味依赖的活动定位在 火蜥蜴嗅球。 神经外科医生可以更准确地定位主要致痫区域 如果他们能在中间找出癫痫灶的话 时间间隔。由于癫痫灶中的神经元据说有一些 在间隔时间内去极化，电压敏感染料可能 用于定位这些单元格。我们计划在模型系统上进行实验以 测试两种可能的本地化方法的可行性。

All of the objectives of this project involve the use of optical methods for monitoring neuron activity. These methods are based on the finding that certain dyes, when bound to membranes, change their optical properties in response to changes in membrane potential. In invertebrate ganglia optical monitoring detects the individual action-potentials in individual cell bodies. Using a 124 element photodiode array positioned in a microscope image plane we have been able to monitor the activity of many neurons of Aplysia or Pleurobranchaea buccal ganglia. We think we are approaching the capability of monitoring most of the spike activity in such preparations. This would provide a powerful tool for determining all of the neurons active during particular behaviors and for testing hypothese about neuronal control of simple behaviours. We are particularly interested in the nuronal basis of simple forms of learning. Additional behavioral experiments and optical measurements in semi-intact preparations are proposed for the immediate future. These would be followed by attempts to determine how the interactions between neurons changed to accomplish the behavior. In vertebrate nervous systems optical monitoring does not yet have single cell resolution. The signals represent average changes in membrane potential of the neurons and processes imaged onto the individual detectors. At present it is possible to measure changes in activity in rat sensory cortex in response to whisker movement or light flashes. We plan experiments to improve the signal-to-noise ratio in these experiments, to develop the use of optical measurements in cat visual cortex, and to determine if there is odor dependent localization of activity in the salamander olfactory bulb. Neurosurgeons could more accurately locate primary epileptogenic areas of cortex if they could identify epileptic foci in the inter-siezure interval. Since neurons in the epileptic foci are said to be somewhat depolarized during the intersiezure interval, voltage sensitive dyes might be used to locate these cells. We plan experiments on model systems to test the feasibility of two possible approaches toward localization.