中文摘要：

昼夜循环对人类和其他动物的生理和行为有着巨大的影响。光照条件能影响动物的视觉成像,并通过向大脑中的生物钟中心发送信号来调整生理和行为的节律。环境光向生物钟传递信号的系统包含了一个复杂的神经递质复合体-受体-第二信使系统。在夜间曝光能迅速启动下丘脑视交叉上核中大量相关的早期基因。此外,许多白天活动的物种,通常都是在光照条件下获得认知。本文综述了环境光对哺乳动物睡眠、生物节律、大脑认知能力和基因表达等生理和行为方面的影响。

英文摘要：

The light-dark cycle is powerful influence on the behaviour and physiology of mammal.In addition to influencing the perception of visual images,light coordinates the temporal rhythms of physiology and behaviour by sending signals to structures in the brain that contain the central circadian clock.The transmission of information about the photic environment to the circadian clock involves a complex array of neurotransmitters,receptors,and second messenger systems.Exposure of an animal to light during the subjective night initiates rapid transcription of a number of immediate-early genes in the suprachiasmatic nucleus of the hypothalamus.Humans and other diurnal species usually exposed to light while engaged in cognitive tasks.We review recent neuroimaging studies which demonstrate the influence of the environmental light on sleep,circadian rhythms,brain cognitive tasks and genes expression.