Imaging Study of Single Neuron Computation in Leech

9604799 Wessel生物物理神经机制如何相互作用以实现神经电路正常运行所需的计算？在很大程度上，由于神经活动的光学成像的最新进展，我们现在相信，单个神经元比以前从单电极研究中所知的要复杂得多，也更动态。最近发展了一种电极记录和光学成像相结合的方法来研究水蚤的神经系统。这种方法的结合将被用来研究单个神经元树突中突触输入的整合。以下具体问题将被问到：(1)对感觉突触输入的非线性反应的细胞学基础是什么？(2)神经元的某些部分是否作为相对独立的功能单位？水蛭为空间延伸的神经元提供了来自过去工作的证据，用于非平凡的处理。已建立的神经元回路和可识别神经元之间在解剖上的局部联系在单个神经元计算的研究中特别有利。因此，可以刺激一个或多个已识别的细胞与研究中的细胞进行突触前反应，并监测突触后电位沿神经元突起的动态相互作用。此外，由于水蛭神经节中神经元的数量很少，因此可以在网络环境下理解单个神经元的计算。拟议的项目将把我们对神经元计算的理解从单个神经元的生物物理机制扩展到产生行为的小型神经元网络的集体计算。由于结果集中在单个神经细胞的属性上，它们可能会推广到所有物种，包括人类。

9604799 Wessel How do biophysical neuronal mechanisms interact to achieve the computations required for proper function of neural circuits? Largely due to recent advances in optical imaging of neuronal activity we now believe that the single neuron is far more complex and dynamic than previously known from single electrode studies. A combination of electrode recording and optical imaging methods on the nervous system of he leech has been developed recently. This combination of methods will be used to investigate the integration of synaptic inputs in the dendrites of single neurons. The following specific questions will be asked: (1) What is the cellular basis of a non-linear response to sensory synaptic inputs ? (2) Do portions of a neuron act as relatively independent functional units ? The leech offers spatially extended neurons with evidence, from past work, for non- trivial processing. The established neuronal circuitry and anatomically localized connections between identifiable neurons in the leech are particularly advantageous in the study of single neuron computation. It is thus possible to stimulate one or more identified cells presynaptic to the cell under study, and monitor the dynamic interaction of postsynaptic potentials along neuronal processes. In addition, due to the small number of neurons in the leech ganglion, single neuron computation can be understood within the network context. The proposed project will extend our understanding of neuronal computation from the level of biophysical mechanisms of single neurons to the collective computation of a small neuronal network that produces behavior. Since the results focus on the properties of single nerve cells, they will likely generalize to all species, including humans.