SYNAPTIC INTEGRATION AND PROPAGATION IN CA1 DENDRITES

中枢神经系统中的每个神经元都有一棵重要的树突 它从上千个突触中的大多数接受输入 神经元。突触输入相互作用，与被动的 枝晶的电结构，并具有电压门控沟道 树突、胞体和轴突在一个复杂的过程中，通常被称为 突触整合。这些电子相互作用主要发生在 树状结构树确定神经元是否在给定时间发送 通过动作电位向下传播向其网络合作伙伴发送信号 轴突。因此，树枝状晶在决定 神经元在其网络中的功能，但人们对此知之甚少 它们的电学特性，部分是由于它们的小尺寸，这是 使得树突很难记录下来。然而，最近， 已经开发出允许贴片吸管记录被 通常由脑片中的神经元树突制成。这个 这里提出的实验利用了这项技术，通常使用 同一神经元上两个点的同时记录，目标是 更好地了解脑内突触整合的过程 海马锥体神经元的树突。 来自海马体和树突的同步斑点吸管记录 海马区CA1区锥体神经元已发现动作电位是 始发于这些神经元的胞体附近。因此，至关重要的是 知道突触电位在传播过程中衰减了多少 树突朝向胞体，以了解如何有效 树突突触正在产生动作电位放电。这 问题将通过直接检查衰减来解决 树突状细胞和体细胞记录部位之间的突触电位。AS 然而，突触电位从树突向胞体传播， 它们可能受到树突电压门控通道的影响，该通道由 突触去极化。这些渠道对世界经济的贡献 因此，将通过检查以下影响来研究EPSP的传播 不同通道阻滞剂对“EPSPS”传播的影响 通过树枝状补片的EPSC形状的电流注入 移液管。此外，为了理解超极化的作用和 分流抑制EPSPS从树突向细胞的传播 SOMA，当前注射模仿IPSCs或局部注射的效果 将考察GABA在树枝晶中的应用。 以及关于树枝状电压门控的作用的信息 在塑造EPSP传播中的渠道和抑制，详细 海马神经元树突中电压传播的描述 将被用来构建现实的分区传播模型 神经元，应该被证明是有用的，研究人员检查的作用 这些神经元在神经网络中负责学习过程 和记忆。

Each neuron in the central nervous system has a substantial dendritic tree that receives input from the majority of the thousands of synapse on the neuron. Synaptic inputs interact with one another, with the passive electrical structure of the dendrites, and with voltage-gated channels in the dendrites, soma, and axon in a complex process, often referred to as synaptic integration. These electrical interactions, occurring largely in the dendritic tree, determine whether at a given time a neuron sends a signal to its network partners via an action potential propagation down the axon. Dendrites therefore have a prominent role in determining the function of a neuron in its network, yet relatively little is known about their electrical properties, in part due to their small size, which has rendered dendrites difficult to record from. Recently, however, techniques have been developed that allow patch-pipette recordings to be made routinely from the dendrites of neurons in brain slices. The experiments proposed here make use of this technique, often using simultaneous recordings from two points on the same neuron, with the goal of better understanding the process of synaptic integration in the dendrites of hippocampal pyramidal neurons. Simultaneous patch-pipette recordings from the soma and dendrites of hippocampal CA1 pyramidal neurons have revealed that action potentials are initiated near the soma of these neurons. It is therefore critical to know how much synaptic potentials are attenuated as they propagate from the dendrites toward the soma, in order to understand how effective dendritic synapses are at producing action potential firing. This question will be addressed by directly examining the attenuation of synaptic potentials between dendritic and somatic recording sites. As synaptic potentials propagate from the dendrites toward the soma, however, they may be affected by dendritic voltage-gated channels activated by the synaptic depolarization. The contribution of such channels to the propagation of EPSPs will therefore be studied by examining the effects of various channel blockers on the propagation of "EPSPs", simulated by using current injection in the shape of an EPSC through a dendritic patch pipette. Furthermore, to understand the role of hyperpolarization and shunting inhibition on the propagation of EPSPs from the dendrites to the soma, the effects of current injections mimicking IPSCs, or local application of GABA to dendrites, will be examined. Together with information concerning the roles of dendritic voltage-gated channels and inhibition in shaping EPSP propagation, the detailed description of voltage propagation in the dendrites of hippocampal neurons will be used to construct realistic compartmental propagation models of neurons that should prove useful to investigators examining the role of these neurons in neural networks responsible for the processes of learning and memory.