OPTICAL STUDIES OF NEURON FUNCTION

这项研究的长期目标是得出一般 局部回路神经元的功能原理，特别是 这些细胞有突触输出， 区域（例如，树-树突触）， 低于尖峰阈值的分级突触传递。 的 当前的目标是了解 无脊椎动物系统，蟹的口胃神经节 北方癌症。 本研究的重点将是实验 旨在阐明钙离子在口胃细胞中的作用， 功能 问题将包括：1）什么时候是电压依赖性 钙内流主要是由于分级电压变化（幽门 节奏），什么时候它主要是由于尖峰？ 钙是否流入 随着细胞类型、神经元内的位置或 突触或神经调质活性？ 2)神经调质是如何 影响静息时体内钙浓度和电压- 在不同区域的识别细胞依赖钙内流？ 本研究中使用的方法包括：细胞内体细胞和 神经电生理记录，同时测量内部 使用不同区域的单个神经元的钙波动 钙指示剂染料偶氮胂III和光电二极管阵列， 和静息内部钙浓度的测量， Fura 2和CCD相机。 当然，大多数神经元研究 功能在空间上受到限制：细胞内电极 仅在一个或两个同时的位置放置， 细胞，通常是索马。 这项研究将提供一个机会， 观察整个神经元在正常范围内的行为 因为它使用了可能被认为是最重要的行为， 有趣的离子钙

The long-term objective of this study is to derive general principles for the functioning of local circuit neurons, especially those cells which have synaptic output from their integrating regions (e.g., dendro-dendritic synapses) and which may use graded synaptic transmission below the threshold for spikes. The immediate objective is to understand the functioning of an invertebrate system, the stomatogastric ganglion of the crab Cancer borealis. The focus of this study will be experiments designed to elucidate the role of calcium in stomatogastric cell function. Questions will include: 1) When is voltage-dependent calcium influx due mostly to graded voltage changes (the pyloric rhythm) and when is it due mostly to spikes? Does calcium influx vary with the cell type, the location within the neuron, or with synaptic or neuromodulator activity? 2) How do neuromodulators affect the resting internal calcium concentration and the voltage- dependent calcium influx in different regions of identified cells? Methods to be used in this study include: intracellular somatic and neuropil recording, simultaneous measurements of internal calcium fluctuations in different regions of single neurons by use of the calcium indicator dye Arsenazo III and a photodiode array, and measurements of resting internal calcium concentrations with Fura 2 and CCD camera. Of necessity, most studies of neuron function have been constrained spatially: intracellular electrodes are placed in only one or two simultaneous locations in single cells, typically the soma. This study will provide an opportunity to look at the behavior of an entire neuron during its normal range of behaviors as it uses what might be considered its most interesting ion, calcium.