Project 1: Cortical Dynamics of Top-Down Control in Visual Active Sensing

项目1：视觉主动感知中自上而下控制的皮层动力学

• 批准号: 10175034
• 负责人: Josef Parvizi
• 金额: $ 25.34万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-04-15 至 2023-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10175034
• 关键词: Alpha Rhythm; Anatomy; Attention; Auditory; Behavior; Behavioral; Brain; Code; Cues; Data; Discrimination; Electrocorticogram; Electrodes; Environment; Epilepsy; Exploratory Behavior; Eye Movements; Frequencies; Functional Magnetic Resonance Imaging; Goals; Human; Link; Location; Macaca; Measures; Memory; Modeling; Monkeys; Neurobiology; Neurons; Neurosciences; Operative Surgical Procedures; Parietal Lobe; Patients; Perception; Performance; Periodicity; Peripheral; Phase; Process; Psychophysics; Rest; Role; Saccades; Sampling; Sensory; Signal Transduction; Stimulus; Structure; Study models; Surface; System; Testing; Thalamic structure; Time; Uncertainty; Visual; Visual Cortex; Visual Perception; Visual attention; Visuospatial; Work; auditory processing; base; directed attention; experimental study; instrument; network models; neural correlate; neuroimaging; neuromechanism; predictive modeling; relating to nervous system; response; sample fixation; theories

Visual perception is limited by two fundamental rhythms, a 7-10 Hz theta/alpha rhythm that describes fluctuations in psychophysical performance and a 3-5 Hz rhythm related to saccadic eye movements. The structure of a task may impose or entrain an additional rhythm, such as when a target stimulus follows a cue at a fixed interval. The goal of this project is to identify in humans the neural correlates of these rhythms and determine their relationship to intrinsic rhythms of spontaneous activity. Neural activity is measured using electrocorticography (ECoG) in patients undergoing surgery for epilepsy. In Expt. 1, localizers are conducted to identify electrodes that respond to saccadic eye movements, foveal stimuli, and/or show spatially selective responses to peripheral stimuli. Functional magnetic resonance imaging is used to identify the large-scale brain network associated with each electrode. In Expt. 2 subjects are cued to detect a target under conditions of temporal uncertainty. In the one-location condition, the target only appears at the cued location. In the two- location condition, the target appears equi-probably at one of two locations. Consistent with previous studies indicating a fixed sampling rhythm, performance should fluctuate in the 1-location condition at twice the frequency as the fluctuations in each location of the 2-location condition. We then identify the neural correlate(s) of this rhythm in electrodes identified by the localizer. These correlates may be associated with local field potentials, modulations of band-limited power, or phase-amplitude relationships that couple low frequencies to high frequencies. In addition, we determine whether these correlates can be identified in intrinsic activity measured at rest. Expt. 3 compares the 1-location and 2-location conditions when the interval between the cue and target is fixed, corresponding to a task-imposed rhythm and temporal certainty. The question is whether the neural correlates of the task-imposed rhythm are independent of the intrinsic rhythms measured in Expt. 2. Finally, Expt. 4 compares the neural rhythms that are generated when subjects process foveal stimuli during a sequence of saccades as compared to the same foveal stimuli when fixation is maintained. We test the hypothesis that saccades produce a phase reset that aligns the maximal excitability phase of internal rhythms with incoming sensory signals. This hypothesis predicts that high gamma sensory evoked responses and behavioral performance should be facilitated by saccades. We also determine the relationship between the neural correlates of the saccadic rhythm, the 7-10 Hz sampling rhythm, and spontaneous rhythms measured at rest. We will interact closely with Project 2, which uses 2 of these tasks in monkey intracortical recordings, and with Projects 3 and 4 that study parallel auditory tasks in humans and monkeys, respectively. Along with Project 3, we will supply data to dynamical network modeling studies (Project 5), and use their findings to refine and/or modify our paradigms as work progresses. Integration of findings across these studies will build more robust models of brain mechanisms operating in Active Sensing.

视觉感知受到两种基本节奏的限制，一种7 - 10 Hz的θ/α节奏， 心理物理表现的波动和与扫视眼球运动相关的3 - 5 Hz节律。的 任务的结构可以施加或夹带额外的节奏，例如当目标刺激跟随一个提示时， 固定的间隔。该项目的目标是识别人类这些节律的神经相关性， 决定了它们与自发活动的内在节律的关系。神经活动是用 皮质电图（ECoG）在癫痫手术患者中的应用。在Expt. 1、定位器进行 识别响应扫视眼球运动、中央凹刺激和/或显示空间选择性电极 对周围刺激的反应。功能性磁共振成像用于识别大范围的 与每个电极相连的大脑网络。在Expt. 2名受试者被提示在一定条件下探测目标 时间的不确定性。在单位置条件下，目标只出现在提示位置。在两个- 位置条件下，目标等可能出现在两个位置之一。与之前的研究一致 表示固定的采样节奏，性能应该在1位置条件下以两倍于 频率作为2位置条件的每个位置的波动。然后我们识别出 在由定位器识别的电极中的该节律的相关性。这些相关因素可能与 局部场电位、带限功率的调制或耦合低的相位-幅度关系 频率到高频率。此外，我们确定这些相关性是否可以在 在休息时测量的内在活性。实验3比较了1-位置和2-位置条件， 提示和目标之间的时间间隔是固定的，对应于任务施加的节奏和时间确定性。的 问题是，任务施加的节奏的神经相关是否独立于内在节奏 在实验中测量。2.最后，expt。图4比较了受试者在处理过程中产生的神经节律， 与注视时相同的中央凹刺激相比， 树立政治意识我们测试的假设，扫视产生一个相位重置对齐的最大兴奋性 与传入的感觉信号的内部节奏的相位。这一假说预测，高伽马传感器 诱发反应和行为表现应该通过扫视来促进。我们还确定 扫视节律、7 - 10 Hz采样节律的神经相关物之间的关系，以及 在休息时测量的自发节律。我们将与项目2密切互动，项目2使用了其中的两个任务， 猴子皮层内记录，以及研究人类平行听觉任务的项目3和项目4， 猴子，分别。沿着项目3，我们将为动态网络建模研究提供数据 （项目5），并使用他们的发现来完善和/或修改我们的工作进展的范式。一体化 这些研究的发现将建立更强大的主动感知大脑机制模型。