ANALYSIS OF GRADED VISUAL SIGNALS

我们将研究突触整合，区域膜特性， 食管上神经节神经元内钙的控制 巨大的藤壶藤壶 我们特别，但不是 只对视觉神经元的这些特性感兴趣 通过分级电位处理和传递信息的通路 而不是动作电位。 藤壶神经节有几个有利的 形态学和生理学特征用于研究这些特性。 大多数这些事件发生在树突或突触前末梢 细胞，因此不能容易地使用微电极检查。 我们将 使用压敏染料的光学方法来同时记录 从单个细胞上的许多位置，包括精细过程。 与 这项技术，我们将确定被动膜性能在许多 电池上的位置，离子电导机制的区域变化， 突触的位置和突触电位的传播 cell. 对于某些选定的神经元，我们将尝试将所有这些联合收割机 将其转化为统一的电气模型。 此外，我们将研究 中间神经突触前末梢内钙的控制 光感受器 这是一个非疲劳的分级突触的例子。 使用用于膜电位测量的相同装置， 将测量染料Arsenazo III吸收的变化， 不同部位和不同条件下体内钙的变化 光感受器中的生理条件。

We will study synaptic integration, regional membrane properties, and control of internal calcium in neurons of the supraesophageal ganglion of the giant barnacle Balanus nubilus. We are particularly, but not exclusively, interested in these properties in neurons in the visual pathway where information is processed and transmitted by graded potentials and not action potentials. The barnacle ganglion has several advantageous morphological and physiological features for studying these properties. Most of these events occur on the dendrites or presynaptic terminals of cells and hence cannot be easily examined using microelectrodes. We will employ optical methods using voltage-senstive dyes to record simultaneously from many positions on individual cells, including fine processes. With this technique we will determine passive membrane properties at many positions on the cell, regional variations in ionic conductance mechanisms, synapse locations and the propagation of synaptic potentials within a cell. For some selected neurons, we will attempt to combine all of these properties into a unified electrical model. In addition, we will examine the control of internal calcium in the presynaptic terminal of the median photoreceptor. This is an example of a non-fatiguing, graded synapse. With the same apparatus used for the membrane potential measurements we will measure changes in absorption in the dye Arsenazo III to indicate changes in internal calcium at different positions and under a variety of physiological conditions in the photoreceptor.