THE STOCHASTIC NATURE OF SINGLE NEURONS

单个神经元的随机性质

• 批准号: 6260477
• 负责人: CHRISTOF KOCH
• 金额: $ 23.36万
• 依托单位: CALIFORNIA INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-02-09 至 2006-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6260477
• 关键词: action potentials; calcium channel; electrophysiology; laboratory rat; membrane potentials; neocortex; neural transmission; neuropharmacology; potassium channel; sodium channel; voltage /patch clamp

Much effort has focused in recent years on the temporal precision with which neurons respond to synaptic input or to direct current injection. This precision relates to the crucial issue of the nature of the neuronal code used to represent and transmit information. We propose to quantify the fundamental limits that noise places on temporal precision by measuring and analyzing the various noise sources, including (i) noise due to the stochastic nature of voltage-dependent ionic channels, (ii) the effect of "spontaneous" synaptic background firing and (iii) the noise introduced by the unreliable, probabilistic nature of synaptic transmission. 1. We intend to experimentally characterize these noise sources in neocortical neurons using pharmacological manipulations which allow us to isolate the contribution of individual noise sources like Na+, K+ or Ca2+ channels. We will use whole-cell patch recordings at the soma and dendrites of single neurons, and in pairs of connected neurons of an in vitro preparation, visualized using infrared optics. 2. We will repeatedly inject frozen current noise into the soma, the dendrite and the presynaptic neuron (using dual electrodes), and record the noise in the post-synaptic potential (sub-threshold PSPs) as well as the fitter in timing of the resulting spike train. This will allow us to compute the mutual information between the injected current and the output spike train. 3. We will compare these measurements with analytical and numerical models of thermal, channel and synaptic noise in weakly- active linear cables, obtained by incorporating the detailed morphology (that we will reconstruct following infra-cellular injection of biocytin) and the electrophysiological properties of these cells. 4. We will use theoretical techniques to derive measures of spike fitter and similarity between spike trains in terms of the noise sources and compare them against the experimental data obtained in step 2. Our research plan will lead to a quantitative picture of the properties of neuronal noise sources and their effect on the information capacity of individual cortical neurons.

近年来，许多努力都集中在神经元对突触输入或直流注入的时间精度上。该精度涉及用于表示和传输信息的神经元代码性质的关键问题。我们建议通过测量和分析各种噪声源来量化噪声在时间精度上的基本限制，包括（i）由于电压依赖性离子频道的随机性质而引起的噪声，（ii）“自发”突触背景触发和（iii）噪声引入了不可靠的概率，概率，概率，概率，概率的传播。 1。我们打算使用药理学操纵来实验表征新皮质神经元中的这些噪声源，这使我们能够隔离Na+，K+或Ca2+通道等单个噪声源的贡献。我们将在单个神经元的SOMA和树突上使用全细胞斑块记录，并使用红外光学器件可视化的体外制剂的一对连接神经元。 2。我们将反复将冷冻的电流噪声注入SOMA，树突和突触前神经元（使用双电极），并在后突触后电势（亚阈值PSP）以及所得峰值列车的时机中记录噪声。这将使我们能够计算注射电流和输出尖峰列车之间的共同信息。 3。我们将将这些测量值与弱势线性电缆中的热，通道和突触噪声的分析和数值模型进行比较，并通过结合详细的形态（我们将在非细胞细胞注射生物囊蛋白后重建）和这些细胞的电生理特性获得。 4。我们将使用理论技术在噪声源中得出尖峰钳工和相似性的度量，并将其与步骤2中获得的实验数据进行比较。我们的研究计划将导致神经元噪声源及其对单个皮质神经元信息的影响的定量图片。