Copp N H, McKenzie T
J Exp Zool. 1984 May;230(2):219-28. doi: 10.1002/jez.1402300207.
The development of amphibian sensory systems and behavior is generally considered to proceed normally without reference to sensory experience during embryonic or larval stages. Most of the supporting research, however, has concentrated on the retinotectal (visual) systems of anurans and has ignored behaviors directed by other sensory systems. We demonstrate that early exposure to light is necessary for the development of photopositive behavior in Xenopus laevis tadpoles, a behavior probably directed by the pineal complex. Light-deprivation during the tadpoles' first 10 days of development results in a long-lasting reduction in the tadpoles' light preference. The development of a strong light preference is not influenced by light-deprivation before the tadpoles are 2 days old or after the tadpoles are 10 days old, but light-deprived tadpoles recover a weak light preference after subsequent days of rearing in the light. Lengthening the tadpoles' exposure to light during the first 10 days of development produces increasingly strong light preferences. Considering the important role of the pineal complex in guiding phototactic behaviors in anurans, we suggest that light-deprivation alters photopositive behavior in Xenopus tadpoles by altering the development of the pineal complex.
两栖动物感觉系统和行为的发育通常被认为在胚胎期或幼体期不依赖感觉经验就能正常进行。然而，大多数支持性研究都集中在无尾两栖类动物的视网膜顶盖（视觉）系统上，而忽略了由其他感觉系统引导的行为。我们证明，早期暴露于光对于非洲爪蟾蝌蚪的趋光行为的发育是必要的，这种行为可能是由松果体复合体引导的。蝌蚪发育的前10天处于光照剥夺状态会导致蝌蚪对光的偏好长期降低。在蝌蚪2日龄之前或10日龄之后进行光照剥夺，不会影响强烈的光偏好的形成，但在随后的光照饲养几天后，光照剥夺的蝌蚪会恢复较弱的光偏好。在发育的前10天延长蝌蚪的光照时间会产生越来越强烈的光偏好。考虑到松果体复合体在引导无尾两栖类动物趋光行为中的重要作用，我们认为光照剥夺通过改变松果体复合体的发育来改变非洲爪蟾蝌蚪的趋光行为。
