Perceptual And Motor Decisions In The Primate Brain

灵长类动物大脑的感知和运动决策

基本信息

批准号：
8149159
负责人：
Kirk G Thompson
金额：
$ 93.65万
依托单位：
NATIONAL EYE INSTITUTE
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/8149159
关键词：
Brain Motor Primates

项目摘要

In the Unit on Perception and Action we investigate how visual inputs are transformed into perception and behavior. Most of our research has been focused on the frontal eye field (FEF), an area in the prefrontal cortex that converts visual information into eye movement commands. We have shown that FEF combines visual inputs with cognitive knowledge to form a priority map of visual space that identifies the location of the most important objects in the visual scene to guide gaze. During the past year we have extended this finding to show that spatially selective signals in the frontal cortex enhance visual processing leading to object recognition (ref. 1) and the formation of complex object representations in the visual cortex (ref. 2). We also described mechanisms by which FEF neurons cooperate and compete to select targets for saccades during visual search (ref. 3). In ref. 1 we investigated the link between neuronal activity in the frontal eye field and the enhancement of visual processing associated with covert spatial attention. We found that FEF activity was correlated with performance accuracy and reaction time in monkeys manually reporting the identity of a visual search target in the absence of eye movements. Chemical inactivation of FEF produced spatially selective perceptual deficits that were correlated with the effectiveness of the inactivation and were strongest on trials that require a voluntary attention shift. These results demonstrate a strong functional link between FEF activity and covert spatial attention, and suggest that spatial signals from FEF directly influence visual processing during the time that a stimulus to be identified is being processed by the visual system. In ref. 2 we addressed the question of how we locate and identify objects in complex natural environments by simultaneously recording single neurons from two brain regions that play different roles in this familiar activity the frontal eye field, an area in the prefrontal cortex that is involved in visual spatial selection, and the inferotemporal cortex (IT), which is involved in object recognition in monkeys performing a covert visual search task. Although the monkeys reported object identity, not location, neural activity specifying target location was evident in FEF before neural activity specifying target identity in IT. These two distinct processes were temporally correlated implying a functional linkage between the end-stages of where and what visual processing and indicating that spatial selection is necessary for the formation of complex object representations associated with visual perception. In ref. 3 we investigated the role of spike rate versus spike timing in visual target selection. We simultaneously recorded activity from multiple frontal eye field neurons and asked whether they interacted to select targets from distractors during visual search. When both neurons in a pair selected the target and had overlapping receptive fields, they cooperated more than when one or neither neuron in the pair selected the target. Elevated spike timing coincidences occurred at the time of attentional selection of the target by both neurons. Decreased spike timing coincidences occurred between neurons with spatially non-overlapping receptive fields at the time of attentional selection of the target by one of the neurons. These results provide evidence for dynamic and task-dependent cooperation and competition among frontal eye field neurons during visual target selection. These studies have extended our understanding of visual processing. We have shown that the frontal eye field provides top-down cognitively-derived signals that modulate ongoing visual processing. We also have identified two separate and dissociable cognitive processes within the frontal eye field, visual selection and saccade preparation. Both of these processes are crucial for normal vision and for interacting with the world. With this knowledge we can design experiments to investigate the flow of sensory information through the brain as it is transformed into perception and action. This work helps us understand the mechanisms of how the brain focuses attention to make perceptual decisions and guide behavior, which is necessary to be able to understand and treat eye movement and attention-related disorders in humans.

在感知和行动的单位中，我们研究了视觉输入如何转化为感知和行为。我们的大多数研究都集中在额叶眼场（FEF）上，这是前额叶皮层中的一个区域，将视觉信息转换为眼动命令。我们已经表明，FEF将视觉输入与认知知识结合在一起，形成了视觉空间的优先级图，该图可以识别视觉场景中最重要的对象的位置以指导凝视。在过去的一年中，我们扩展了这一发现，以表明额叶皮层中的空间选择性信号增强了视觉处理，从而导致对象识别（参考文献1）和视觉皮层中复杂对象表示形成（参考文献2）。我们还描述了FEF神经元合作并竞争视觉搜索过程中扫视目标的机制（参考文献3）。在参考1我们研究了额眼场中神经元活性与与秘密空间关注相关的视觉处理之间的联系。我们发现，FEF活性与猴子中的性能准确性和反应时间相关，并在没有眼动的情况下手动报告了视觉搜索目标的身份。 FEF的化学灭活产生了与失活有效性相关的空间选择性知觉缺陷，并且在需要自愿注意的试验中最强烈。这些结果表明，FEF活动与秘密空间注意力之间存在牢固的功能联系，并表明FEF的空间信号直接影响视觉处理，因为在视觉系统正在处理要识别的刺激的过程中。在参考2 we addressed the question of how we locate and identify objects in complex natural environments by simultaneously recording single neurons from two brain regions that play different roles in this familiar activity the frontal eye field, an area in the prefrontal cortex that is involved in visual spatial selection, and the inferotemporal cortex (IT), which is involved in object recognition in monkeys performing a covert visual search task. 尽管猴子报告了对象的身份，而不是位置，但在FEF中明显在神经活动中指定目标身份的神经活动是显而易见的。这两个不同的过程在时间上是相关的，这意味着在何处和哪种视觉处理的终点之间存在功能链接，并表明空间选择对于形成与视觉感知相关的复杂对象表示形成是必需的。在参考3我们研究了尖峰速率与尖峰时序在视觉目标选择中的作用。我们同时记录了来自多个额眼视野神经元的活动，并询问它们在视觉搜索过程中是否相互作用以从干扰器中选择目标。当一对中的两个神经元选择目标并具有重叠的接收场时，它们的合作超过了一对中一个神经元选择目标时的合作。两种神经元在注意靶标注意目标时发生了升高的时序巧合。在一个神经元注意目标选择目标时，神经元之间具有空间非重叠接收场的神经元之间的峰值正时巧合减少。这些结果为视觉目标选择过程中额眼野外神经元之间的动态和任务依赖性合作以及竞争提供了证据。这些研究扩展了我们对视觉处理的理解。我们已经表明，额眼场提供了自上而下的认知信号，可调节正在进行的视觉处理。我们还确定了额叶视野中的两个独立且可解散的认知过程，视觉选择和扫视准备。这两个过程对于正常视力和与世界互动至关重要。有了这些知识，我们可以设计实验，以研究感觉信息通过大脑转化为感知和动作的流动。这项工作有助于我们了解大脑如何将注意力集中在做出感知决策和指导行为的机制，这对于能够理解和治疗人类的眼睛运动和注意力相关的疾病是必不可少的。