From Branch to Branch: Unravelling Primate Vision in Arboreal Leaping and Navigation

灵长类动物，包括人类及其非人类近亲，对物体识别、空间视觉以及社会线索的检测和处理等任务具有高度派生的视觉。早期的视皮层在冠群灵长类动物的起始处经历了显著的变化，初级视皮层(V1)出现了几乎不变的视觉回路。这种建筑设计在灵长类动物的大脑进化过程中一直被保存下来，并伴随着专用于视觉的新皮质的扩张。在小鼠狐猴(Microcebus Murinus)，一种类似于灵长类最后共同祖先的基本灵长类动物中，V1覆盖了新皮质的20%。然而，这种架构提供的视觉能力和行为与人类、猿类和东半球猴子的视觉能力和行为有很大不同。在这里，我们提出了一个研究计划，以调查早期灵长类视觉的关键特征。使用ethoLoop平台，我们将在受控的自然主义实验室环境中研究自由放养的老鼠狐猴的行为、认知和感知，类似于它们的树生栖息地。该平台能够对复杂任务期间的视觉导航、觅食行为和神经元记录进行定量研究。通过调整环境条件，我们可以探索视觉参数并推断计算原理。该项目结合了量化生态行为、理论神经科学和计算机视觉以及自由放养的老鼠狐猴的神经记录方面的专业知识。这项研究旨在了解树栖动物导航和觅食过程中的视觉处理和认知。目的1：了解树栖跳跃中主动视觉的策略：为了描述视觉引导跳跃所涉及的不同模式和策略，我们将设计一种新颖的、可参数化的行为跳跃任务，受马达加斯加自然环境中实际观察到的物理特征的限制。目的2：描述不同视觉条件下的大规模导航策略：为了更好地了解视觉条件如何影响导航策略，我们将在实验室环境中观察自由移动的老鼠狐猴，模拟它们的行为，并在受控条件下检验我们的预测。目的3：揭示小鼠狐猴大脑中视觉、凝视、姿势和空间的神经元编码：为了表征视觉和非视觉特征(包括运动和姿势参数)的编码，我们将利用电生理学和便携式微型显微镜成像技术记录单个神经元在自由运动条件下的活动。综上所述，我们的研究将开启灵长类视觉活动的新视角，定义了人类大脑中仍在使用的视觉回路的大部分形式，并解决了几个主要的悬而未决的问题，即灵长类大脑中的视觉信息处理与近亲啮齿动物的视觉信息处理之间的潜在差异。

Primates, including humans and their non-human relatives, possess a highly derived sense of vision for tasks such as object recognition, spatial vision, and detecting and processing of social clues. The early visual cortex underwent a significant transformation at the origin of crown group primates, with the emergence of a near invariant form of vision circuitry in the primary visual cortex (V1). This architectural design has been conserved throughout primate brain evolution and was accompanied by an expansion of neocortex dedicated to vision. In the mouse lemur (Microcebus murinus), a basal primate resembling the primate last common ancestor, V1 covers 20% of the neocortex. However, the visual capabilities and behaviors served by this architecture differ greatly from those in humans, apes, and Old World monkeys. Here we propose a research program to investigate key features of early primate vision. Using the EthoLoop platform, we will study behavior, cognition, and perception in free-ranging mouse lemurs in a controlled naturalistic laboratory setting resembling their arboreal habitat. This platform enables quantitative studies of visually guided navigation, foraging behaviors, and neuronal recording during complex tasks. By adjusting environmental conditions, we can explore visual parameters and infer computational principles. The project combines expertise in quantifying ecological behaviors, theoretical neuroscience and computer vision, and neural recording in free-ranging mouse lemurs. The research aims to understand visual processing and cognition during arboreal navigation and foraging. Aim 1: Understanding the strategies of active vision during arboreal leaping: To characterize the different modalities and strategies involved in visually guided leaping, we will design a novel, parameterizable behavioral leaping task, constrained by physical features actually observed in natural settings in Madagascar. Aim 2: Characterizing large scale navigation strategies under varying visual conditions: To gain a better understanding of how the visual conditions affect navigational strategies we will observe freely moving mouse lemurs in the wild, model their behavior and test our predictions under controlled conditions in the laboratory settings. Aim 3: Revealing the neuronal codes for vision, gaze, posture and space in the mouse lemur brain: To characterize the coding of visual and non-visual features (including motor and posture parameters) we will record the activity of individual neurons under freely moving conditions using electrophysiologyy and portable miniature microscope imaging. Taken together, our studies will open a new perspective on primate vision in action that defined much of the form of vision circuitry still used in the human brain and address several major open questions about potential differences between visual information processing in the primate brain and in that of closely related rodents.