Effect of oscillations on coding and connectivity in monkey sensorimotor cortex

描述(申请人提供)：研究大脑的电生理学家必须经常选择是观察森林还是观察树木：脑电(EEG)和局部场电位(LFP)测量大量神经元的宏观振荡，而单位记录测量单个细胞产生的微观电位。我们建议在经常观察到高频(10-45赫兹)振荡的运动皮质中研究这两者之间的关系。这些振荡显然受到行为的调节，但一些作者认为，它们是缺乏运动的大脑皮层失活的症状，而另一些人则认为，它们在大脑皮层分布区域的感觉运动整合中发挥了作用。众所周知，振荡会影响许多运动皮质细胞产生的动作电位的时序，但这种效应的意义--发生在两个分析水平的交叉点--还没有被很好地理解。我们建议研究这些振荡的行为相关性，以及振荡结构对神经元棘波中编码和交流的信息的影响。我们将使用高密度、100电极阵列植入行为猴的初级运动前皮质、腹侧前运动前皮质和背侧前运动前皮质，记录运动前皮质和运动前皮质的单个单位和LFP。这些猴子已经接受了训练，可以执行简单的伸手任务，包括向视觉指导的目标重复移动。在最初的一组实验中，我们将尝试分离与选择和计划运动相关的振荡活动与与保持静止姿势相关的活动。在第二组实验中，我们将检查LFP功率和相位对神经尖峰编码的运动学信息的影响。在第三组实验中，我们将使用统计方法和更直接的方法，通过评估在正在进行的全球振荡的不同阶段施加的电刺激的传播，来检查振荡结构对功能连通性的影响。公开声明：无论是在疾病中还是在健康中，全球振荡都是大脑活动的标志；它们与注意力、感觉和记忆等高级功能有关，在帕金森病和癫痫等病理过程中发挥着重要作用。尽管振荡是大脑活动的一个普遍特征，但目前还不清楚振荡对神经信息处理有什么影响。我们将使用高密度多电极阵列记录行为猴子的大脑活动，并使用这些数据来评估振荡对参与产生运动行为的神经电路的影响。

DESCRIPTION (provided by applicant): Electrophysiologists studying the brain must often choose whether to observe the forest or the trees: electroencephalogram (EEG) and local field potentials (LFP) measure macroscopic oscillations in large populations of neurons, while single unit recordings measure microscopic potentials generated by single cells. We propose to examine the relationship between these two in motor cortex, where high frequency (10- 45Hz) oscillations are commonly observed. These oscillations are clearly modulated by behavior, but some authors have argued that they are a symptom of cortical inactivation in the absence of movement, while others have suggested they serve a role in sensorimotor integration across distributed regions of cortex. It is well known that oscillations affect the timing of action potentials generated by many motor cortical cells, but the significance of this effect - which occurs at the intersection of two levels of analysis - is not well understood. We propose to examine the behavioral relevance of these oscillations and the effect of oscillatory structure on the information encoded and communicated in neuronal spikes. We will record single units and LFPs from motor and pre-motor cortex using high-density, 100-electrode arrays implanted in primary motor, ventral pre-motor, and dorsal pre-motor cortex in behaving monkeys. These monkeys have been trained to perform simple reaching tasks that involve repeated movements to visually-instructed targets. In an initial set of experiments, we will attempt to dissociate the oscillatory activity associated with selecting and planning a movement with the activity associated with maintaining a stationary posture. In a second set of experiments, we will examine the impact of LFP power and phase on the kinematic information encoded in neural spiking. In a third set of experiments, we will examine the effect of oscillatory structure on functional connectivity using both statistical methods and more directly by assessing the propagation of electrical stimulation applied at different phases of the ongoing global oscillation. Public Statement: Global oscillations are a hallmark of brain activity in both sickness and in health; they have been related to higher order functions such as attention, sensation, and memory, and they play an important role in pathologies such as Parkinson's disease and epilepsy. Despite being a ubiquitous feature of brain activity, it is not clear what effect, if any, oscillations have on neural information processing. We will record brain activity in behaving monkeys using high-density multi-electrode arrays, and use this data to assess the effects of oscillations on the neural circuitry involved in generating motor behavior.