Linking Neural Population Activity and Visual Perception

描述(由申请人提供)：拟议研究的总体目标是定量了解灵长类初级视觉皮质(V1)的神经活动与视觉检测和辨别任务中的行为表现之间的联系。为了实现这一目标，训练猴子使用可能单独出现或在视觉面具上出现的小定向视觉刺激来执行四项要求苛刻的视觉检测和辨别任务。当猴子执行这些任务时，我们使用电压敏感的染料光学成像与电生理学相结合，来监测V1中的神经群活动。然后，我们使用计算技术来研究视觉刺激、在多个空间尺度上测量的神经反应和对这些刺激的观察到的行为反应之间的关系。我们的前两个目标集中在这三个变量之间的两个基本因果关系上。在目标#1中，我们的目标是确定V1神经元群体如何表示或编码有关目标和掩蔽的视觉信息。我们解决了三个主要问题：(I)V1反应在多个空间尺度上提供给视觉系统其余部分的信号的质量如何，(Ii)这些信息在V1中是如何分布的，以及(Iii)从V1中提取这些信息的最佳方式是什么？为了形成关于目标的决定，V1之后的神经电路必须‘读出’或解码由V1神经元群体提供的神经信号。我们在目标2中的目标是确定V1中的哪些神经元参与了关于目标的知觉决定，以及它们的信号可能如何汇集起来形成这个决定。最后，这两个基本关系--V1神经元对视觉信息的编码，以及后续处理阶段对V1反应的解码--可能会根据行为任务的不同而改变。在目标3中，我们通过调节目标的不确定性和目标的相关性来改变任务。然后，我们检查自顶向下机制是否以及如何根据任务的需求更改V1中目标的表示形式。总而言之，这项研究将极大地扩展我们对灵长类皮质神经元群体表达和处理信息的方式的理解。 与公共健康相关：我们感知、识别和处理环境中的物体的能力是由大脑皮层的神经回路调节的。我们的长期目标是了解大脑皮层的神经回路如何代表和处理视觉信息。通过解决这一目标，我们的研究将有助于阐明大脑皮层的正常功能及其在神经和神经精神疾病中的故障。

DESCRIPTION (provided by applicant): The overall goal of the proposed research is to provide a quantitative understanding of the link between neural activity in the primate primary visual cortex (V1) and behavioral performance in visual detection and discrimination tasks. To achieve this goal, monkeys are trained to perform four demanding visual detection and discrimination tasks using small oriented visual stimuli that could appear in isolation or on top of a visual mask. While the monkey performs these tasks, we use voltage-sensitive dye optical imaging in conjunction with electrophysiology, to monitor neural population activity in V1. We then use computational techniques to study the relationships between the visual stimuli, the measured neural responses at multiple spatial scales, and the observed behavioral responses to these stimuli. Our first two aims focus on two fundamental causal relationships between these three variables. In Aim #1 our goal is to determine how visual information regarding the target and the mask is represented, or encoded, by populations of V1 neurons. We address three primary questions: (i) what is the quality of the signals that are provided to the rest of the visual system by V1 responses at multiple spatial scales, (ii) how is this information distributed in V1, and (iii) what is the optimal way to extract this information from V1? To form a decision regarding the target, neural circuits subsequent to V1 must 'read out', or decode, the neural signals provided by populations of V1 neurons. Our goal in Aim #2 is to determine which neurons in V1 contribute to the perceptual decision regarding the target, and how their signals might be pooled to form this decision. Finally, these two fundamental relationships - the encoding of visual information by V1 neurons, and the decoding of V1 responses by subsequent processing stages - may change, depending on the behavioral task. In Aim #3, we vary the task by modulating target uncertainty and target relevance. We then examine if and how top-down mechanisms change the representation of the target in V1 based on the demands of the task. Together, this research will significantly expand our understanding of the way in which information is represented and processed by populations of neurons in the primate cortex. PUBLIC HEALTH RELEVANCE: Our ability to perceive, recognize, and act upon objects in our environment is mediated by neural circuits in the cerebral cortex. Our long-term goal is to understand how neural circuits in the cerebral cortex represent and process visual information. By addressing this goal, our research will help to elucidate the normal function of the cerebral cortex and its malfunction in neurological and neuropsychiatric disease.