Dynamic Neuronal Organizations in Neocortex

描述(申请人提供)：这项研究的长期目标是了解群体神经元事件的组织(数百万神经元的相关活动)。该方案研究了激励波的传播(也称为。行波)。传播波发生在感觉和运动过程中，也发生在癫痫等神经疾病期间。控制传播速度和方向的机制对于确定电波将携带什么样的活动模式并在何时将其传递到大脑皮层的哪个部分非常重要。人们对传播方向和速度的控制知之甚少。这是因为波在具有平行和多突触路径的分布式神经元网络中传播。 这一提议将检验一种假设，即传播波是由耦合的本地振子产生的。局域振子之间的相位关系决定了速度和方向。电压敏感染料成像将被用来可视化在体外产生的新皮质切片中的传播波。 提出了三个具体目标来研究两种“theta”(4-12赫兹)振荡和一种诱发的伽马振荡中的局域振荡器。目标1由两个实验组成。一项实验将可视化本地振荡器和它们之间的边界。另一项实验将试图通过对大脑皮层组织的微切割来分离单独的局部振荡器。目标2将检验关于切向大脑皮层切片中产生的二维波的假设。目标3将研究诱发伽马振荡的神经元组成。将对单个神经元的放电活动进行光学监测，试图了解单个神经元的活动是如何构成群体振荡的。 这项研究不仅有助于了解正常的大脑皮质过程，也有助于了解癫痫发作活动在大脑皮质的启动和扩散，这种活动扰乱了约1%的美国人口的生活。

DESCRIPTION (provided by applicant): The long-term objective of this study is to understand the organization of population neuronal events (correlated activities of millions of neurons). This proposal studies the propagation of excitation waves (a.k.a. traveling waves) in the neo-cortex. Propagating waves occur during sensory and motor processes as well as during neurological disorders such as epilepsy. The mechanisms that control the propagating velocity and directions are important in determining what kind of activity patterns will be carried by the wave and delivered to what part of the cortex, and at what time. Very little is known about the control of the propagating direction and velocity. This is because the waves travel in a distributed neuronal network with parallel and polysynaptic pathways. This proposal will test a hypothesis that propagating waves are generated by coupled local oscillators. The phase relationship among the local oscillators determines the velocity and direction. Voltage-sensitive dye imaging will be used to visualize the propagation waves generated in vitro, in neo-cortical slices. Three Specific Aims are proposed to study the local oscillators during two kinds of "theta" (4-12 Hz) oscillations and an evoked gamma oscillation. Aim 1 consists of two experiments. One experiment will visualize the local oscillators and the boundaries between them. The other experiment will try to separate individual local oscillators with micro cuts to the cortical tissue. Aim 2 will test the hypothesis on the two-dimensional waves generated in tangential cortical slices. Aim 3 will study the neuronal-composition of an evoked gamma oscillation. The spiking activity of individual neurons will be optically monitored in an attempt to understand how the activities of individual neurons compose a population oscillation. This study will not only contribute to the understanding of normal cortical processing but also to the understanding of the initiation and spreading of epileptic seizure activity in the cortex that disrupts the life of about 1% of the U.S. population.