Kawasaki Masashi, Kinoshita Michiyo, Weckström Matti, Arikawa Kentaro
Laboratory of Neuroethology, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Japan.
Department of Biology, University of Virginia, Charlottesville, VA, 22904, USA.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2015 Dec;201(12):1115-23. doi: 10.1007/s00359-015-1039-y. Epub 2015 Sep 2.
The eyes of the Japanese yellow swallowtail butterfly, Papilio xuthus, contain six spectral classes of photoreceptors, each sensitive either in the ultraviolet, violet, blue, green, red or broadband wavelength regions. The green-sensitive receptors can be divided into two subtypes, distal and proximal. Previous behavioral and anatomical studies have indicated that the distal subtype appears to be involved in motion vision, while the proximal subtype is important for color vision. Here, we studied the dynamic properties of Papilio photoreceptors using light stimulation with randomly modulated intensity and light pulses. Frequency response (gain) of all photoreceptor classes shared a general profile-a broad peak around 10 Hz with a declining slope towards higher frequency range. At 100 Hz, the mean relative gain of the distal green receptors was significantly larger than any other receptor classes, indicating that they are the fastest. Photoreceptor activities under dim light were higher in the ultraviolet and violet receptors, suggesting higher transduction sensitivities. Responses to pulse stimuli also distinguished the green receptors from others by their shorter response latencies. We thus concluded that the distal green receptors carry high frequency information in the visual system of Papilio xuthus.
日本黄凤蝶（Papilio xuthus）的眼睛包含六种光谱类型的光感受器，每种光感受器分别对紫外光、紫光、蓝光、绿光、红光或宽带波长区域敏感。绿色敏感光感受器可分为两种亚型，远端型和近端型。先前的行为学和解剖学研究表明，远端亚型似乎参与运动视觉，而近端亚型对颜色视觉很重要。在这里，我们使用强度随机调制的光刺激和光脉冲研究了凤蝶光感受器的动态特性。所有光感受器类别的频率响应（增益）具有共同特征——在10Hz左右有一个宽峰，向更高频率范围斜率下降。在100Hz时，远端绿色光感受器的平均相对增益显著大于其他任何光感受器类别，表明它们是最快的。在暗光条件下，紫外光和紫光感受器中的光感受器活动较高，表明转导敏感性较高。对脉冲刺激的反应也通过较短的反应潜伏期将绿色光感受器与其他光感受器区分开来。因此，我们得出结论，远端绿色光感受器在日本黄凤蝶的视觉系统中携带高频信息。
