Department of Hydrobiology, Faculty of Biology, University of Warsaw at Biological and Chemical Research Centre, Żwirki i Wigury 101, 02-089 Warsaw, Poland
Laboratory of Neurodegeneration, International Institute of Molecular and Cell Biology in Warsaw, Księcia Trojdena 4, 02-109 Warsaw, Poland.
Biol Open. 2020 Jul 21;9(7):bio047779. doi: 10.1242/bio.047779.
Numerous studies have indicated that temperature improves the visual capabilities of different ectotherms, including a variety of fish species. However, none of these studies has directly tested whether elevated temperature extends the visual detection distance - the distance from which a visual stimulus is detected. To test this hypothesis, we investigated the effect of temperature on the visual detection distance of zebrafish () larvae by measuring the largest distance from a moving target that induced a neural response in the optic tectum. We applied advanced methods of functional calcium imaging such as selective plane illumination microscopy in combination with a miniature OLED screen. The screen displayed an artificial, mobile prey, appearing in the visual field of the larvae. We performed experiments in three temperature treatments (18, 23 and 28°C) on transgenic fish expressing a fluorescent probe (GCaMP5G) that changes intensity in response to altered Ca concentrations in the nerves in the optic tectum. Based on the obtained data, we also measured three additional parameters of the neural response in the optic tectum, each being a proxy of sensitivity to changes in the stimulus movement. We did not confirm our hypothesis, since the visual detection distance shortened as the temperature increased. Moreover, all of the three additional parameters indicated a negative effect of the temperature on the speed of the neural response to the stimuli. However, the obtained results could be explained not only by worse visual capabilities at the elevated temperature, but also by the differences in the visual field and in turn, the retinotopic location of the visual stimulus between the temperature treatments, since the stimulus in the experiments moved horizontally rather than forward and backward from the fish's eye.
大量研究表明，温度能提高包括多种鱼类在内的不同变温动物的视觉能力。然而，这些研究都没有直接测试温度是否能延长视觉检测距离——即从视觉刺激被检测到的距离。为了验证这一假设，我们通过测量引起视顶盖神经反应的最大移动目标距离，来研究温度对斑马鱼幼虫视觉检测距离的影响。我们应用了先进的功能钙成像方法，如选择性平面照明显微镜与微型 OLED 屏幕相结合。屏幕显示出一个人工的、移动的猎物，出现在幼虫的视野中。我们在三个温度处理（18、23 和 28°C）下对表达荧光探针（GCaMP5G）的转基因鱼进行了实验，该探针的强度会根据视顶盖神经中钙浓度的变化而改变。基于获得的数据，我们还测量了视顶盖神经反应的另外三个参数，每个参数都是对刺激运动变化敏感性的代理。我们没有证实我们的假设，因为随着温度的升高，视觉检测距离缩短了。此外，所有这三个额外的参数都表明温度对刺激神经反应速度有负面影响。然而，获得的结果不仅可以用在较高温度下较差的视觉能力来解释，还可以用不同的视野来解释，从而用刺激在不同温度处理之间的视网膜位置来解释，因为在实验中刺激是水平移动的，而不是从鱼眼向前或向后移动。
