Cellular analysis of mammalian circadian rhythms

动物记住重大情况发生的时间，然后预测这些情况在连续几天再次发生的能力，可能具有巨大的适应意义。包括人类在内的动物的日常活动在一定程度上是由生物钟驱动的，生物钟随着环境和有机体内部条件的变化而优化有机体的生理和行为。我们的研究旨在了解动物如何记住重大事件的时间、地点和严重性，然后对向它们暗示在类似条件下也会发生类似后果的条件做出反应。位于视交叉上核的下丘脑昼夜节律时钟对这些事件的习得和回忆并不是必需的。我们的研究检查了昼夜节律振荡器，或称振荡器，负责记录一天中发生重大事件的时间，然后向生物体发出信号，说明类似情况再次发生的可能性和时间。 我们将研究重点放在海马体的作用上，因为它在学习、记忆和处理上下文关系的能力中起着重要作用。我们和其他人测量了HPC内细胞活动的明显昼夜节律。我们的一般假设是，所有的HPC细胞都具有内在的节律性。这意味着，一个可能与特定空间中的重要体验相关的细胞星座也将是有节奏的。因此，这些细胞的节律将向生物体发送关于一天中的时间以及以前经历的条件或学习的关系可能再次发生的概率的特定信息！

The ability of animals to remember the time of day that significant conditions occur, then to anticipate the recurrence of those conditions on successive days, can have enormous adaptive significance. The daily activity of animals, including human beings, is driven in part by biological clocks that optimize the organism's physiology and behaviour with the changing conditions in the environment as well as within the organism itself. Our research is aimed at understanding how animals can remember the time, location and severity of significant happenings, then react to conditions that suggest to them that under similar conditions, similar consequences will occur. The well described hypothalamic circadian clock in the suprachiasmatic nucleus, is not necessary for the acquisition nor recall of these events. Our research examines the circadian oscillator, or oscillators, that are responsible for registering the time of day that significant events occur, then signalling to the organism, the likelihood that similar conditions are going to occur again, and at what time. We have focused our studies on the role of the hippocampus because it is instrumental in the ability to learn, remember, and act upon contextual relationships. We and others have measured a distinct circadian rhythmicity in cellular activity within the HPC. Our general hypothesis is that all HPC cells are intrinsically rhythmic. This means that a constellation of cells that might be associated with a significant experience in a defined space, would also be rhythmic. As such the rhythm in those cells would send to the organisms specific information about time of day and the probabilty that previously experienced conditions or learned relationships, are likely to occur again!!!