Dynamics of Kv channel function in identified populations of pyramidal neurons in neocortex

我们的研究旨在阐明离子通道如何调节脑内神经元的信息处理。 大脑皮层，即神经元将突触输入转换为动作电位的不同机制。这个 拟议的实验将确定电压门控钾(Kv)通道如何调节的基本原理 5层(L5)新皮质锥体神经元(PNS)传入的突触后处理。PNS是输出像元 大脑皮层和在学习、记忆和感觉运动处理中的关键角色，以及中枢 神经系统疾病(如癫痫)。拟议中的研究超越了标准概念，即钾 通道对兴奋性起到内在的刹车作用。它们旨在确定Kv2和Kv7的影响 频道有关于L5 PN响应的信息类型以及该信息以前是如何过滤的 下行传输。我们将研究两类金字塔的发射行为控制机制 神经元：脑内投射(IT)和锥体束(PT)型，由两个遗传鉴定的PN代表，GFP在L5 PNS群体中表达，受独特基因ETV1(IT)和TY1控制 (PT)。我们将测试有关Kv2和Kv7通道如何调节突发发射的假设(目标1)和 连续激发(重复爆发和阈值上的共振：目标2)。KV通道属性和 表情是动态的。它们可以根据活动或信号通路发生可塑性变化，并 从而改变神经元的过滤特性。因此，我们还将研究与使用相关的本征可塑性 兴奋性(目标3)。我们使用转基因小鼠品系和最先进的电生理方法， 包括体细胞/树突状细胞配对记录，动态钳制，内管灌流，有核补片和 细胞内贴片记录，以及全细胞和穿孔贴片。我们也使用双光子和 基于电荷耦合器件(CCD)的钙离子成像系统。我们的刺激方案旨在模仿 到达神经元胞体(所有树突的共同总结点)的自然突触活动 系统地变化，以模拟不同的投入水平或构成。我们的发现将会有重大的 皮质处理、离子通道功能、理解神经计算和机制的含义 潜在的癫痫、麻醉、学习和记忆。

Our research is aimed at elucidating how ion channels regulate the processing of information by neurons in the cerebral cortex, i.e., the diverse mechanisms neurons use to convert synaptic input into action potentials. The proposed experiments will determine basic principles of how voltage-gated potassium (Kv) channels regulate postsynaptic processing of inputs in layer 5 (L5) neocortical pyramidal neurons (PNs). PNs are the output cells of cortex and key players in learning, memory, and sensorimotor processing, as well as the targets of central nervous system diseases (e.g., epilepsy). The proposed studies go beyond the standard notion that potassium channels act as an intrinsic brake on excitability. They are designed to determine the influence Kv2 and Kv7 channels have on the types of information that L5 PNs respond to and how that information is filtered before downstream transmission. We will study mechanisms controlling firing behavior in two classes of pyramidal neurons: intratelencephalic-projecting (IT) and pyramidal tract (PT) type, represented by two genetically-identified PNs with GFP expressed in populations of L5 PNs under control of unique genes: etv1 (IT) and thy1 (PT). We will test hypotheses concerning how Kv2 and Kv7 channels regulate burst firing (Aim 1) and continuous firing (repetitive bursting and suprathreshold resonance: Aim 2). Kv channel properties and expression are dynamic. They can undergo plastic changes in response to activity or signaling pathways and thus change neuronal filtering properties. Thus, we will also study use-dependent plasticity of intrinsic excitability (Aim 3). We use transgenic mouse lines and state-of-the-art electrophysiological approaches, including somatic / dendritic paired recordings, dynamic clamp, internal pipet perfusion, nucleated patch and on-cell patch recordings, as well as whole cell and gramicidin perforated patch. We also use two-photon and charge-coupled device (CCD)-based Ca2+ imaging systems. Our stimulus protocols are designed to mimic natural synaptic activity arriving at the soma of a neuron (the common summing point for all dendrites) and will be systematically varied to simulate different levels or composition of inputs. Our findings will have major implications for cortical processing, ion channel function, understanding neural computations, and mechanisms underlying epilepsy, anesthesia, learning and memory.