Goller Benjamin, Fellows Tyee K, Dakin Roslyn, Tyrrell Luke, Fernández-Juricic Esteban, Altshuler Douglas L
Physiol Biochem Zool. 2019 Sep/Oct;92(5):481-495. doi: 10.1086/705124.
Hummingbirds are an emerging model for studies of the visual guidance of flight. However, basic properties of their visual systems, such as spatial and temporal visual resolution, have not been characterized. We measured both the spatial and temporal visual resolution of Anna's hummingbirds using behavioral experiments and anatomical estimates. Spatial visual resolution was determined behaviorally using the optocollic reflex and anatomically using peak retinal ganglion cell densities from retinal whole mounts and eye size. Anna's hummingbirds have a spatial visual resolution of 5-6 cycles per degree when measured behaviorally, which matches anatomical estimates (fovea: cycles per degree; area temporalis: cycles per degree; and whole eye average: ). To determine temporal visual resolution, we used an operant conditioning paradigm wherein hummingbirds were trained to use a flickering light to find a food reward. The limits of temporal visual resolution were estimated as 70-80 Hz. To compare Anna's hummingbirds with other bird species, we used a phylogenetically controlled analysis of previously published data on avian visual resolutions and body size. Our measurements for Anna's hummingbird vision fall close to and below predictions based on body size for spatial visual resolution and temporal visual resolution, respectively. These results indicate that the enhanced flight performance and foraging behaviors of hummingbirds do not require enhanced spatial or temporal visual resolution. This finding is important for interpreting flight control studies and contributes to a growing understanding of avian vision.
蜂鸟正成为飞行视觉引导研究的一个新兴模型。然而，它们视觉系统的基本特性，如空间和时间视觉分辨率，尚未得到描述。我们通过行为实验和解剖学估计来测量安娜氏蜂鸟的空间和时间视觉分辨率。空间视觉分辨率通过行为学方法利用视动反射来确定，通过解剖学方法利用视网膜全层标本的视网膜神经节细胞峰值密度和眼睛大小来确定。行为学测量时，安娜氏蜂鸟的空间视觉分辨率为每度5 - 6周，这与解剖学估计值相符（中央凹：每度 周；颞叶区域：每度 周；全眼平均值： ）。为了确定时间视觉分辨率，我们采用了一种操作性条件反射范式，在该范式中训练蜂鸟利用闪烁的光来寻找食物奖励。时间视觉分辨率的极限估计为70 - 80赫兹。为了将安娜氏蜂鸟与其他鸟类进行比较，我们对先前发表的关于鸟类视觉分辨率和体型的数据进行了系统发育控制分析。我们对安娜氏蜂鸟视觉的测量结果分别在基于体型对空间视觉分辨率和时间视觉分辨率的预测值附近及以下。这些结果表明，蜂鸟增强的飞行性能和觅食行为并不需要增强的空间或时间视觉分辨率。这一发现对于解释飞行控制研究很重要，并有助于增进对鸟类视觉的理解。
