眼睛朝前的动物如灵长类需要将两只眼睛对准同一方向，以便使左眼和右眼的图像融合，而不管头部怎样动。Jason Kerr及其同事发现，啮齿类的眼睛协调遵从一个不同的策略。利用一个定制的微型化“眼睛-摄像系统”，他们发现，对自由运动的大鼠来说，眼睛运动的作用是，使两只眼睛的视场在头顶上连续重叠，但未必要对准同一方向。大鼠是在地面上生活的动物，经常受到来自上面的威胁，所以这种策略可能是作为对来自头顶的捕食者不断保持警惕的一种手段而形成的。（生物谷Bioon.com）
生物谷推荐英文摘要：
Nature doi:10.1038/nature12153
Rats maintain an overhead binocular field at the expense of constant fusion
Damian J. Wallace, David S. Greenberg, Juergen Sawinski, Stefanie Rulla, Giuseppe Notaro & Jason N. D. Kerr
Fusing left and right eye images into a single view is dependent on precise ocular alignment, which relies on coordinated eye movements. During movements of the head this alignment is maintained by numerous reflexes. Although rodents share with other mammals the key components of eye movement control, the coordination of eye movements in freely moving rodents is unknown. Here we show that movements of the two eyes in freely moving rats differ fundamentally from the precisely controlled eye movements used by other mammals to maintain continuous binocular fusion. The observed eye movements serve to keep the visual fields of the two eyes continuously overlapping above the animal during free movement, but not continuously aligned. Overhead visual stimuli presented to rats freely exploring an open arena evoke an immediate shelter-seeking behaviour, but are ineffective when presented beside the arena. We suggest that continuously overlapping visual fields overhead would be of evolutionary benefit for predator detection by minimizing blind spots.
