Attentional Modulation of Neuronal Communication

描述（由申请人提供）：像选择性注意这样的认知操作被认为涉及多个大脑区域中神经元集合的协调活动。很明显，注意力增强了整个视觉系统中神经元的局部集合内的视觉反应，注意力也促进了不同皮层层和不同皮层区域中神经元集合之间视觉输入的传递的推论还没有得到彻底的研究。类似地，虽然人们普遍认为低水平视觉处理的注意力调节是由高阶网络控制的，但对自上而下控制的具体回路和生理过程还没有很好的理解。考虑到这两个问题，本项目的总体目标是确定在低水平视觉处理中注意力对前馈通信的影响的大小和生理机制。使用的组合尖峰相关性，标准的一致性和格兰杰因果关系分析，我们将分析数据从多电极记录在V1和V2在猴子执行一个单一的，充分研究（联运）的注意力任务。我们已经表明，由于在这种范式中的刺激节奏的可预测性，注意可以使用低频振荡作为工具，以增强神经元对任务相关刺激的反应。这一发现具有广泛的影响，因为节奏和可预测性在自然行为的许多方面都很突出。为了进一步研究，我们将检验以下假设：注意可以使用低频振荡相位同步来促进视觉通路中神经元集合之间的前馈通信。我们的具体目标是：1）描述注意力对皮层之间前馈传输的影响，2）描述注意力对V1和V2之间传输的影响，3）定义层间和真实间相互作用的注意力调制的脑机制。同时采样的层流电流源密度（CSD）和多单位活动（MUA）的配置文件在V1和V2将索引突触活动和发射模式的神经元合奏在关键位置的颗粒上，颗粒和颗粒下层。V1和V2中注意力效应的分层曲线，沿着格兰杰因果关系分析将有助于区分几种替代控制回路。对这些位置的神经元放电模式的刺激前和刺激后振荡动力学以及相关变化的单次试验分析将有助于将动力学与潜在生理学联系起来。 公共卫生相关性：我们的方法允许使用猴子作为理解人类ERP和EEG产生的神经元机制的模型。这项研究还将提供一个数据集，可用于评估为人类开发的新功能连接分析，特别是那些针对癫痫研究的分析。

DESCRIPTION (provided by applicant): Cognitive operations like selective attention are thought to involve coordinated activity of neuronal ensembles in multiple brain areas. It is abundantly clear that attention enhances visual responses within local ensembles of neurons throughout the visual system, the corollary idea that attention also facilitates the transmission of visual inputs between neuron ensembles in different cortical layers and in different cortical regions has not been thoroughly investigated. Similarly, while it is generally agreed that attentional modulation of low level visual processing is controlled by a higher order network, the specific circuits and physiological processes by which top-down control is imposed are not well understood. With these two problems in mind the overall goal of this project is to define the magnitude and physiological mechanisms of attention's influence on feedforward communication in low level visual processing. Using a combination of spike correlation, standard coherence and Granger causality analyses, we will analyze data from multielectrode recordings in V1 and V2 in monkeys performing a single, well-studied (intermodal) attention task. We have shown that because of the predictability of stimulus rhythms in this paradigm, attention can use low frequency oscillations as instruments to enhance neuronal responses to task relevant stimuli. This finding has wide ramifications because rhythm and predictability are prominent in many aspects of natural behavior. To follow it up, we will test the hypothesis that attention can use low frequency oscillatory phase synchrony to facilitate feedforward communication between neuronal ensembles in the visual pathways. Our specific aims are: 1) to characterize attention's influence on feedforward transmission between cortical layers, 2) to characterize attention's influence on transmission between V1 and V2, and 3) to define the brain mechanisms underlying attentional modulation of interlaminar and interareal interactions. Concurrent sampling of laminar current source density (CSD) and multiunit activity (MUA) profiles in V1 and V2 will index synaptic activity and firing patterns in neuronal ensembles at key locations in the supragranular, granular and infragranular layers. Laminar profiles of attention effects in V1 and V2, along with Granger causality analyses will help to differentiate between several of the alternative control circuits. Single trial analysis of both pre- stimulus and poststimulus oscillatory dynamics and of related variations in neuronal firing patterns in these locations will help to relate dynamics to underlying physiology. PUBLIC HEALTH RELEVANCE: Our methods allow use of the monkey as a model for understanding the neuronal mechanisms of ERP and EEG generation in humans. This study will also provide a data set that can be used to evaluate new functional connectivity analyses developed for use in humans, particularly those targeting the study of epilepsy.