Dynamic Neuronal Organizations in Neocortex

描述（由申请人提供）：本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）。该提案研究了激发波（a.k.a.行波）在新皮层中。在感觉和运动过程中以及在诸如癫痫的神经系统疾病中发生震颤波。控制传播速度和方向的机制在确定波将携带何种活动模式并在何时传递到皮层的哪个部分方面很重要。关于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通路的分布式神经元网络中传播。 这个提议将检验传播波是由耦合的本振子产生的假设。本振子之间的相位关系决定了速度和方向。将使用电压敏感染料成像来可视化新皮层切片中体外产生的传播波。 本文提出了三个具体的目标来研究两种“theta”（4-12 Hz）振荡和诱发γ振荡中的本振子。目标1包括两个实验。一个实验将可视化本地振荡器和它们之间的边界。另一个实验将试图通过对皮层组织的微切割来分离单个本地振荡器。目标2将测试在切向皮质切片中产生的二维波的假设。目的3将研究诱发伽马振荡的神经元组成。单个神经元的尖峰活动将被光学监测，以试图了解单个神经元的活动如何构成群体振荡。 这项研究不仅有助于理解正常的皮层处理，也有助于理解大脑皮层中癫痫发作活动的启动和传播，这种活动扰乱了大约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.