Visual pursuit behavior in mice maintains the pursued prey on the retinal region with least optic flow.
Visual pursuit behavior in mice maintains the pursued prey on the retinal region with least optic flow.
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DOI：
10.7554/elife.70838
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发表时间：
2021-10-26
期刊：
影响因子：
7.7
通讯作者：
Kerr JN
中科院分区：
文献类型：
--
作者：
Holmgren CD;Stahr P;Wallace DJ;Voit KM;Matheson EJ;Sawinski J;Bassetto G;Kerr JN
小鼠有一个大的视野，通过前庭眼反射（VOR）驱动的眼睛旋转来对抗头部旋转，从而不断稳定。在保持其广泛的视觉覆盖范围有利于发现捕食者的同时，老鼠也利用视觉追踪和捕获猎物。然而，在自由运动的动物中，量化物体在视场中的位置是一个挑战。在这里，我们开发了一种方法来数字化重建和量化自由移动的老鼠执行基于视觉的猎物捕获任务的视觉场景。通过分离视觉，将小鼠眼光学模型与头部和眼睛旋转相结合，将数字环境和视网膜特征的详细重建投影到角膜表面进行比较，并在整个行为过程中进行更新。通过量化视觉场景中物体的空间位置及其在整个行为中的运动，我们表明猎物图像始终落在vr稳定视野的小区域内。这个功能焦点与视野内最小光流区域一致，因此在追逐过程中，老鼠直接向猎物奔跑时，运动引起的图像模糊最小。功能焦点位于视网膜上颞部，与报道的α - on持续视网膜神经节细胞的高密度区域一致。老鼠有很多东西要盯着。为了生存，它们需要躲避陆地和天空上的捕食者，同时也要追捕作为它们食物一部分的小昆虫。为了做到这一点，它们有很大的全景视野，从头部后面和上方延伸到鼻子下面。当它们在觅食时，为了稳定它们的视线，老鼠反射性地移动它们的眼睛来对抗它们头部的运动：事实上，它们无法独立移动它们的眼睛。这就提出了一个问题：这些啮齿类动物在追踪猎物时使用了它们大视野的哪一部分，又有什么优势？这是很难调查的，因为它需要同时测量老鼠追逐和捕捉昆虫时眼睛和头部的运动。为此，Holmgren， Stahr等人开发了一种新技术，可以记录小鼠在高分辨率数字化环境中捕捉蟋蟀的精确眼睛位置，头部旋转和猎物位置。结合这些信息，研究小组可以用数学方法重现老鼠在追逐昆虫时看到的东西，并评估它们使用的是大视野的哪一部分。这表明，一旦一只蟋蟀进入老鼠视野的任何一部分，啮齿动物就会转移它们的头——而不是眼睛——把猎物带到两只眼睛的视野中，然后直接向它跑去。如果昆虫逃跑了，老鼠就会重复同样的行为。在追逐过程中，蟋蟀的位置主要停留在老鼠视野中的一小块区域，这块区域与老鼠眼睛中被认为有助于追踪物体的特定区域相对应。当动物向前奔跑时，这个区域也允许最小的运动引起的图像模糊。由Holmgren， Stahr等人开发的方法直接揭示了动物在捕猎时看到的东西，以及这种不断变化的观点是如何与眼睛发生的事情联系在一起的。这种方法可以应用于其他物种，开启了一波新的工具来探索自由移动的动物看到了什么，以及行为和神经回路之间的关系。
Mice have a large visual field that is constantly stabilized by vestibular ocular reflex (VOR) driven eye rotations that counter head-rotations. While maintaining their extensive visual coverage is advantageous for predator detection, mice also track and capture prey using vision. However, in the freely moving animal quantifying object location in the field of view is challenging. Here, we developed a method to digitally reconstruct and quantify the visual scene of freely moving mice performing a visually based prey capture task. By isolating the visual sense and combining a mouse eye optic model with the head and eye rotations, the detailed reconstruction of the digital environment and retinal features were projected onto the corneal surface for comparison, and updated throughout the behavior. By quantifying the spatial location of objects in the visual scene and their motion throughout the behavior, we show that the prey image consistently falls within a small area of the VOR-stabilized visual field. This functional focus coincides with the region of minimal optic flow within the visual field and consequently area of minimal motion-induced image-blur, as during pursuit mice ran directly toward the prey. The functional focus lies in the upper-temporal part of the retina and coincides with the reported high density-region of Alpha-ON sustained retinal ganglion cells. Mice have a lot to keep an eye on. To survive, they need to dodge predators looming on land and from the skies, while also hunting down the small insects that are part of their diet. To do this, they are helped by their large panoramic field of vision, which stretches from behind and over their heads to below their snouts. To stabilize their gaze when they are on the prowl, mice reflexively move their eyes to counter the movement of their head: in fact, they are unable to move their eyes independently. This raises the question: what part of their large visual field of view do these rodents use when tracking a prey, and to what advantage? This is difficult to investigate, since it requires simultaneously measuring the eye and head movements of mice as they chase and capture insects. In response, Holmgren, Stahr et al. developed a new technique to record the precise eye positions, head rotations and prey location of mice hunting crickets in surroundings that were fully digitized at high resolution. Combining this information allowed the team to mathematically recreate what mice would see as they chased the insects, and to assess what part of their large visual field they were using. This revealed that, once a cricket had entered any part of the mice’s large field of view, the rodents shifted their head – but not their eyes – to bring the prey into both eye views, and then ran directly at it. If the insect escaped, the mice repeated that behavior. During the pursuit, the cricket’s position was mainly held in a small area of the mouse’s view that corresponds to a specialized region in the eye which is thought to help track objects. This region also allowed the least motion-induced image blur when the animals were running forward. The approach developed by Holmgren, Stahr et al. gives a direct insight into what animals see when they hunt, and how this constantly changing view ties to what happens in the eyes. This method could be applied to other species, ushering in a new wave of tools to explore what freely moving animals see, and the relationship between behaviour and neural circuitry.