Neuroethology Group, Department of Behavioural Biology, Bielefeld University Bielefeld, Germany.
Front Integr Neurosci. 2013 Sep 20;7:68. doi: 10.3389/fnint.2013.00068. eCollection 2013.
The retinal image changes that occur during locomotion, the optic flow, carry information about self-motion and the three-dimensional structure of the environment. Especially fast moving animals with only little binocular vision depend on these depth cues for maneuvering. They actively control their gaze to facilitate perception of depth based on cues in the optic flow. In the visual system of birds, nucleus rotundus neurons were originally found to respond to object motion but not to background motion. However, when background and object were both moving, responses increased the more the direction and velocity of object and background motion on the retina differed. These properties may play a role in representing depth cues in the optic flow. We therefore investigated, how neurons in nucleus rotundus respond to optic flow that contains depth cues. We presented simplified and naturalistic optic flow on a panoramic LED display while recording from single neurons in nucleus rotundus of anaesthetized zebra finches. Unlike most studies on motion vision in birds, our stimuli included depth information. We found extensive responses of motion selective neurons in nucleus rotundus to optic flow stimuli. Simplified stimuli revealed preferences for optic flow reflecting translational or rotational self-motion. Naturalistic optic flow stimuli elicited complex response modulations, but the presence of objects was signaled by only few neurons. The neurons that did respond to objects in the optic flow, however, show interesting properties.
在运动过程中发生的视网膜图像变化，即光流，携带有关自身运动和环境三维结构的信息。特别是那些只有很少双眼视觉的快速移动的动物，依赖于这些深度线索来操纵。它们主动控制注视方向，以便根据光流中的线索感知深度。在鸟类的视觉系统中，最初发现圆核神经元对物体运动有反应，但对背景运动没有反应。然而，当背景和物体都在移动时，随着视网膜上物体和背景运动的方向和速度差异的增大，反应会增加。这些特性可能在表示光流中的深度线索方面发挥作用。因此，我们研究了圆核中的神经元如何对包含深度线索的光流做出反应。我们在全景 LED 显示屏上呈现简化和自然的光流，同时记录麻醉斑马雀圆核中的单个神经元的反应。与鸟类运动视觉的大多数研究不同，我们的刺激包括深度信息。我们发现圆核中的运动选择神经元对光流刺激有广泛的反应。简化刺激显示出对反映平移或旋转自身运动的光流的偏好。自然的光流刺激引起了复杂的反应调制，但只有少数神经元表示物体的存在。然而，那些对光流中的物体有反应的神经元表现出有趣的特性。
