OPTICAL STUDIES OF NEURON ACTIVITY AND ORGANIZATION

这个项目的所有目标都涉及到光学方法的使用 用于监测神经元活动。 这些方法基于以下发现 当某些染料与膜结合时， 对膜电位变化的反应。 在无脊椎动物神经节光学监测检测个人 单个细胞体中的动作电位。 使用124元素 光电二极管阵列定位在显微镜图像平面，我们已经能够 监测许多神经元的活动， 颊神经节 我们认为我们正在接近监测能力， 这类制剂中的大部分尖峰活性。 这将提供 这是一个强大的工具，用于确定所有神经元在特定时间内的活动情况。 行为和测试假设的神经元控制的简单 行为。 我们特别感兴趣的是简单的nuronal基础 学习的形式。 额外的行为实验和光学 半完整制剂中的测量建议立即 未来 随后将尝试确定 神经元之间的相互作用改变来完成行为。 在脊椎动物神经系统中，光学监测还没有单一的 细胞分辨率 这些信号代表细胞膜的平均变化 神经元和过程的潜力成像到个人 探测器 目前，可以测量大鼠活动的变化， 感觉皮层对触须运动或闪光的反应。 我们计划 在这些实验中，为了提高信噪比， 开发猫视觉皮层光学测量的应用，并 确定是否存在气味依赖性的活性定位， 蝾螈嗅球 神经外科医生可以更准确地定位原发性癫痫区域， 如果他们能在大脑皮层中识别出癫痫灶， interval. 由于癫痫灶中的神经元被认为是 电压敏感性染料在间期期间去极化， 用于定位这些细胞。 我们计划在模型系统上进行实验， 测试两种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.