Time matters: Integration of time information into memory processes

2014年，约翰·奥基夫、梅-布里特·莫泽和爱德华德·I·莫泽因在构成大脑定位系统的细胞方面的工作而荣获诺贝尔生理学和医学奖。特殊的细胞，地点和网格细胞，使大脑能够在环境中定位，让我们知道我们在哪里，如何从一个地方导航到另一个地方，形成和表达空间记忆。对于动物来说，空间导航和空间记忆对于增强健康和生存至关重要，这是基于及时重新安置食物来源和交配伙伴以及避免捕食者的基础上的，捕食者通常会建立典型的狩猎路线。但是生物钟和记忆电路是如何连接的呢？最近的一项研究首次表明，果蝇能够形成与时间相关的气味-糖记忆，在这种记忆中，果蝇学会在早上将一种气味与奖励联系起来，在下午将第二种气味与同样的奖励联系起来。作为这一发现的结果，果蝇现在似乎是一个合适的模型系统来识别潜在的时间相关记忆的神经元关联。我将阐述这些记忆在大脑中的存储位置，以及时钟神经元传递的时间信息是如何整合到记忆电路中的。最重要的是，我的目标是解开苍蝇是否能够将时间与空间信息联系起来，以形成时空记忆，这在无脊椎动物(蜜蜂、蚂蚁)和脊椎动物物种(老鼠、老鼠)中是众所周知的。这将使第一次能够识别神经元的关联，使动物能够在正确的时间出现在正确的地点。

In 2014 John O´Keefe, May-Britt Moser and Edvard I. Moser were honored with the Nobel Prize in Physiology and Medicine for their work on cells that constitute a positioning system in the brain. Special cells, place and grid cells, enable the brain to orientate within the environment, allowing us to know where we are, how to navigate from one place to another and to form and express spatial memories. For animals both spatial navigation and spatial memories are essential to enhance fitness and survival based on the timely relocation of food sources and mating partners and the avoidance of predators which often establish typical hunting routes. But how are the circadian clock and memory circuits connected? A recent study illustrated for the first time that Drosophila is able to form time-related odor-sugar memories, where flies learn that one odor is coupled to reward in the morning while a second odor to the same reward in the afternoon. As a result of this finding Drosophila now appears to be a suitable model system to identify the neuronal correlates underlying time-related memories. I will address where in the brain these memories are stored and how time information delivered by clock neurons is integrated in memory circuits. On top, my aim is to unravel whether flies can link time to spatial information in order to form time-place memories, which are well-known in invertebrate (bees, ants) and vertebrate species (rats, mice). This would allow for the first time to identify the neuronal correlates enabling animals to be in the right place at the right time.