Project B: Neural basis of causal inference and sensory updating in trial-based tasks in monkeys

项目摘要 世界的复杂性使感觉信息变得模棱两可。一组横扫视网膜的信号， 例如，可能由移动的物体或动物自身的运动产生。大脑会解决这个问题 通过构建一个内部现实模型，将感觉数据中的模式与 世界，在一个被称为因果推理的过程中。为了支持适应性行动，大脑对所有相关因素的估计 变量必须更新，以保持与当前场景解释下的物理一致，因为 以及彼此之间的关系。该建议侧重于对象运动、自身运动、 和深度。这个项目将测试来自项目A的模型的预测，以了解因果推理应该如何 更新这些相关的感觉变量。基于之前的工作和初步数据，总体假设是 顶叶(7a)和前额叶(8av)区域发出信号，表明物体是否在世界上运动，并且这些区域 信号流经反馈投影以更新MT区域中物体深度的感觉表示 MSTd区域内的自运动速度。该项目的目标是使用传统的、基于试验的任务来确定 是否以及如果是，因果推论被传播回感觉皮质以更新对 猴子体内与任务相关的变量。目标1的目的是测试因果推理是否调节低水平 通过检查光流解析的神经关联来表示运动的感觉，这是 物体运动的感知方向受到背景光学的强烈和可预测的影响 流。目标2将直接测试任务变量的感觉表征是否更新以保持一致性 对世界抱有信念。猴子会判断一个物体是否在世界上移动，并报告它的深度， 而顶叶7a区、前额叶8av区、感觉区MT和MSTd的神经元群 录制好了。由初步行为数据支持的理论框架预测，这一因果关系 对物体运动的推断会在深度和自我运动的估计中产生特定的偏差模式 速度，以及MT和MSTD中运动和深度的神经估计将更新，以保持与 行为。为了确定因果推理和感觉更新所需的神经回路，目标3将 当神经活动被记录在感官上时，用麝香酚或光遗传学来灭活反馈通路 陈述，因为动物执行与目标2相同的任务。目标1应确定该因果关系 推理调节早期的视觉处理，并识别实施这些效果的区域。 目标2将提供因果推理和感觉更新的第一个细胞和神经群体证据 信念传播。目标3将建立一个神经回路，这是调解因果推理和 更新感官表征。总之，成功完成拟议的实验将揭示 因果推理和感觉变量更新的回路机制和建立新的功能作用 自上而下的反馈连接，这是大脑皮层组织的一般特征。

Project Summary The world's complexity makes sensory information ambiguous. A set of signals sweeping across the retina, for instance, might be generated by a moving object or by the animal's own motion. The brain resolves this ambiguity by constructing an internal model of reality that associates patterns in sensory data with events in the world, in a process called causal inference. To support adaptive action, the brain's estimates of all relevant variables must be updated to remain consistent with physics under the current interpretation of the scene, as well as with each other. This proposal focuses on perceptual interactions among object motion, self-motion, and depth. This project will test the predictions of models from Project A for how causal inference should update these related sensory variables. Based on previous work and preliminary data, the overall hypothesis is that parietal (7a) and prefrontal (8av) areas signal whether or not an object moves in the world, and that these signals flow through feedback projections to update sensory representations of object depth in area MT and self-motion velocity in area MSTd. The goal of this project is to use traditional, trial-based tasks to determine whether, and if so how, causal inferences are propagated back to sensory cortex to update representations of task-relevant variables in monkeys. The goal of Aim 1 is to test whether causal inference modulates low-level sensory representations of motion by examining neural correlates of optic flow parsing, a phenomenon in which the perceived direction of an object's motion is strongly and predictably influenced by background optic flow. Aim 2 will test directly if sensory representations of task variables are updated to maintain consistency with beliefs about the world. Monkeys will judge whether an object moves in the world and also report its depth, while neural populations in parietal area 7a, prefrontal area 8av, and sensory areas MT and MSTd are recorded. The theoretical framework, supported by preliminary behavioral data, predicts that this causal inference about object motion will induce specific patterns of bias in estimates of depth and self-motion velocity, and that neural estimates of motion and depth in MT and MSTd will update to remain consistent with behavior. To identify the neural circuitry necessary for causal inference and sensory updating, Aim 3 will inactivate feedback pathways with muscimol or optogenetics while neural activity is recorded in sensory representations, as animals perform the same task as in Aim 2. Aim 1 is expected to establish that causal inference modulates early visual processing, and to identify the areas where these effects are implemented. Aim 2 will provide the first cellular and neural population evidence of causal inference and sensory updating by belief propagation. Aim 3 will establish a neural circuit that is necessary for mediating causal inference and for updating sensory representations. Together, successful completion of the proposed experiments will uncover circuit mechanisms of causal inference and sensory variable updating and establish a new functional role for top-down feedback connections, which are a general feature of cortical organization.