Morin L P, Allen C N
Department of Psychiatry and Graduate Program in Neuroscience, Stony Brook University, Stony Brook, NY 11794, USA.
Brain Res Rev. 2006 Jun;51(1):1-60. doi: 10.1016/j.brainresrev.2005.08.003. Epub 2005 Dec 5.
The primary mammalian circadian clock resides in the suprachiasmatic nucleus (SCN), a recipient of dense retinohypothalamic innervation. In its most basic form, the circadian rhythm system is part of the greater visual system. A secondary component of the circadian visual system is the retinorecipient intergeniculate leaflet (IGL) which has connections to many parts of the brain, including efferents converging on targets of the SCN. The IGL also provides a major input to the SCN, with a third major SCN afferent projection arriving from the median raphe nucleus. The last decade has seen a blossoming of research into the anatomy and function of the visual, geniculohypothalamic and midbrain serotonergic systems modulating circadian rhythmicity in a variety of species. There has also been a substantial and simultaneous elaboration of knowledge about the intrinsic structure of the SCN. Many of the developments have been driven by molecular biological investigation of the circadian clock and the molecular tools are enabling novel understanding of regional function within the SCN. The present discussion is an extension of the material covered by the 1994 review, "The Circadian Visual System."
哺乳动物的主要昼夜节律时钟位于视交叉上核（SCN），它是密集视网膜下丘脑神经支配的接受者。在其最基本的形式中，昼夜节律系统是更大的视觉系统的一部分。昼夜视觉系统的第二个组成部分是视网膜接受性的膝间小叶（IGL），它与大脑的许多部位相连，包括汇聚到视交叉上核靶点的传出神经。IGL还为视交叉上核提供主要输入，视交叉上核的第三个主要传入投射来自中缝核。在过去十年中，对调节各种物种昼夜节律的视觉、膝状体下丘脑和中脑血清素能系统的解剖结构和功能的研究蓬勃发展。关于视交叉上核的内在结构也有了大量同时的详细阐述。许多进展是由对昼夜节律时钟的分子生物学研究推动的，分子工具使人们能够对视交叉上核内的区域功能有新的理解。本讨论是1994年综述《昼夜视觉系统》所涵盖内容的扩展。
