Dynamic mechanisms of active vision in prefrontal cortex

描述(申请人提供)：在自然条件下，我们的视觉体验的特点是眼睛频繁运动，因为我们扫描丰富的视觉环境。然而，大多数实验都专注于视觉和行为贫乏条件下的神经反应，为了便于处理而牺牲了现实条件。人们越来越意识到，大脑在这些条件下的活动并不总是适用于更自然的环境，需要探索更复杂情况下的神经元动力学的实验。这项应用的长期目标是确定灵长类大脑中的神经回路如何在眼睛频繁运动和内部认知状态发生变化的情况下产生连贯的视觉感知。额叶眼场是前额叶皮质的一部分，对控制眼球跳动起着至关重要的作用，它通过其在大脑皮层中的独特位置在这一功能中起着关键作用。FEF神经元兼有视觉和运动功能，与控制眼睛的皮质下结构和视觉皮质区域有联系。FEF神经元如何在这个通道中发挥作用，起到整合视觉信息来引导眼睛运动和向视觉系统通知计划好的运动命令的双重功能？一条线索来自对预测性重新映射现象的研究，在这种现象中，神经元在眼跳即将到来之前改变其空间偏好。这发生在FEF神经元以及其他皮质区域，并暗示了它们的反应特性的频繁和动态变化。汽车规划带来了什么样的动态变化？产生这些动力学所需的信息是如何通过神经元回路传播的？我们将在三个具体目标中解决这些问题，第一个目标是使用快速呈现的稀疏噪声刺激，这是一种在早期视觉区域发展起来的方法，以探索FEF神经元反应的动力学。我们假设FEF神经元具有精确的时间动力学，使其能够对快速闪烁的刺激做出反应，以及非线性空间求和，导致对被视为潜在眼跳目标的小刺激的强烈反应。第二个具体目标是使用相同的噪声刺激以高空间和时间精度测量预测性重新映射的响应。我们假设，重新映射表现为眼跳周围时间段接受野的逐渐移动，这既发生在引导性眼跳中，也发生在更自然主义的自发眼跳中。在第三个特定目标中，我们试图通过同时从一组FEF神经元中记录来分离负责这些动态变化的神经元回路。我们假设，在眼球运动之前，FEF内的局部电路被调用来在神经元之间传递信息。这项研究的总体结果将是确定FEF在主动视觉过程中整合视觉知觉和运动控制的作用，并构建一个框架，使用感受野映射和群体记录来测量视觉和运动系统中神经回路的动态变化。这将有助于开发治疗脑外伤后神经视觉障碍和康复的方法。 受伤或疾病。

DESCRIPTION (provided by applicant): Under natural conditions, our visual experience is characterized by frequent eye movements as we scan a rich visual environment. Most experiments, however, have focused on neural responses under visually and behaviorally impoverished conditions, sacrificing realistic conditions for tractability. There is a growing realization that the brain's activity under these conditions does not always generalize to more natural settings, and experiments that probe neuronal dynamics under more complicated situations are needed. The long-term goal of this application is to determine how neural circuits in the primate brain act to generate coherent visual perception despite frequent eye movements and changes in internal cognitive state. The frontal eye field (FEF), a part of prefrontal cortex critical for controlling saccadic eye movements, plays a key role in this function through its unique position in the cortical hierarchy. FEF neurons serve both visual and motor functions, with connections to subcortical structures that control the eyes and to visual cortical areas. How do FEF neurons act in this gateway, serving the dual functions of integrating visual information to guide eye movements and informing the visual system about planned motor commands? One clue comes from studies of the phenomenon of predictive remapping, in which neurons shift their spatial preferences prior to an impending saccade. This occurs in FEF neurons as well as other cortical areas, and hints at the frequent and dynamic changes in their response properties. What kinds of dynamic changes are brought on by motor planning? How does the information necessary to generate these dynamics propagate through neuronal circuits? We will address these questions in three specific aims, the first of which uses rapidly presented sparse noise stimuli, an approach developed in early visual areas, to probe the dynamics of FEF neuronal responses. We hypothesize that FEF neurons have precise temporal dynamics, enabling responses to rapidly flashed stimuli, and nonlinear spatial summation, leading to strong responses to small stimuli that are perceived as potential saccade targets. The second specific aim is to measure the predictively remapped response with high spatial and temporal precision using the same noise stimulus. We hypothesize that remapping manifests as a gradual shift in the receptive field in the peri-saccadic time period, and this occurs for both guided saccades and more naturalistic spontaneous saccades. In the third specific aim, we attempt to isolate the neuronal circuitry responsible for these dynamic changes by recording simultaneously from a population of FEF neurons. We hypothesize that local circuitry within FEF is invoked to transfer information between neurons prior to an eye movement. The overall result of this study will be to establish the role of FEF in integrating visual perception and motor control during active vision, and to construct a framework for using receptive field mapping and population recordings to measure dynamic changes in neural circuits across visual and motor systems. This will aid in developing treatments for neurological disorders of vision and rehabilitation after traumatic brain injury or disease.