PDF(Pubmed)
Abstract：
Locomotor movements cause visual images to be displaced across the eye, a retinal slip that is counteracted by stabilizing reflexes in many animals. In insects, optomotor turning causes the animal to turn in the direction of rotating visual stimuli, thereby reducing retinal slip and stabilizing trajectories through the world. This behavior has formed the basis for extensive dissections of motion vision. Here, we report that under certain stimulus conditions, two Drosophila species, including the widely studied Drosophila melanogaster, can suppress and even reverse the optomotor turning response over several seconds. Such \'anti-directional turning\' is most strongly evoked by long-lasting, high-contrast, slow-moving visual stimuli that are distinct from those that promote syn-directional optomotor turning. Anti-directional turning, like the syn-directional optomotor response, requires the local motion detecting neurons T4 and T5. A subset of lobula plate tangential cells, CH cells, show involvement in these responses. Imaging from a variety of direction-selective cells in the lobula plate shows no evidence of dynamics that match the behavior, suggesting that the observed inversion in turning direction emerges downstream of the lobula plate. Further, anti-directional turning declines with age and exposure to light. These results show that Drosophila optomotor turning behaviors contain rich, stimulus-dependent dynamics that are inconsistent with simple reflexive stabilization responses.
摘要：
运动导致视觉图像在眼睛上移位，通过稳定许多动物的反射而抵消的视网膜滑移。在昆虫中，视电机转动使动物转向旋转的视觉刺激的方向，从而减少视网膜滑脱并稳定整个世界的轨迹。这种行为形成了广泛解剖运动视觉的基础。这里,我们报告说，在某些刺激条件下，两种果蝇，包括被广泛研究的黑腹果蝇,可以在几秒钟内抑制甚至逆转视电机转动反应。这种“反方向转向”是由持久的，高对比度,缓慢移动的视觉刺激，与促进同步旋转的视觉刺激不同。防转向,比如同步光运动反应，需要局部运动检测神经元T4和T5。小叶板切向细胞的一个子集，CH细胞,参与这些回应。从叶板中的各种方向选择性细胞的成像显示没有与行为匹配的动力学证据，表明观察到的反转方向出现在小叶板的下游。Further,反方向转弯随着年龄和暴露于光线而减少。这些结果表明果蝇的视运动转向行为含有丰富的,与简单的反身稳定反应不一致的刺激依赖动力学。
