Locus coeruleus functional modulation of the hippocampal complex: Behavior and physiology

通过动物研究，科学家们已经能够揭示海马神经元如何产生对空间的表征，即，空间地图我们的假设是，空间地图使我们能够分离记忆，并在不同的位置适当地行事。 显然，我们需要空间记忆来唤起在家庭、工作和许多其他环境中完成任务所需的行为。我们的灵活行为能力取决于将行为与位置联系起来。导航信息帮助我们识别地点。此外，如果我们看到墙壁的形状不同，或者听到新的声音，或者闻到新的气味，我们可能会相信一个地方是不同的。众所周知，大脑中的一小群细胞，蓝斑，会发出变化或新奇的信号，将新奇的信号发送到海马体和大脑的其他部位。这些新奇的信号可能会导致海马地图发生变化，从而允许新的，甚至是矛盾的行为在相似的空间中发生。 最近开发的一种方法允许在两个不同的时间海马空间地图的直接可视化。我们预测，两个空间地图的差异越大，动物在两个相似的环境中就越容易改变它们的行为。将引入一种人造的新奇信号，看看它是否会使地图不同，以及它是否会使对改变过的空间的记忆更强。 这些研究将阐明位置表征是如何形成的，以及它们是否通过分离记忆在支持适应行为中发挥作用。我们的研究对理解两个大脑区域的运作有意义，海马体和蓝斑是阿尔茨海默氏病中最先恶化的区域。这可以帮助我们理解如何支持和增强记忆和适应行为。

Using animal research, scientists have been able to reveal how hippocampal neurons produce a representation of space, i.e., spatial maps. Our hypothesis is that spatial maps enable us to separate memories and behave appropriately in different locations. Obviously, we need spatial memories to call up the behaviors required for tasks at home, at work and in many other contexts. Our ability to behave flexibly depends on connecting behaviors with locations. Navigational information helps us to identify places. Also, we may believe a place is different if we see a different shape to the walls, or hear new sounds, or smell new smells. A small group of cells in the brain, the locus coeruleus, is known to signal changes or novelty, sending a novelty signal to the hippocampus and other parts of the brain. These novelty signals may cause hippocampal maps to change, and thus permit new, and even contradictory, behaviors to occur in similar spaces. A recently developed method allows the direct visualization of hippocampal spatial maps at two different times. We predict that the more different two spatial maps are, the easier it will be for animals to change their behavior in two similar environments. An artificial novelty signal will be introduced to see if it makes maps different and whether it makes memories of altered spaces stronger. These studies will illuminate how representations of location are formed and whether they play a role in supporting adaptive behavior by separating memories. Our research has implications for understanding the operation of two brain areas, the hippocampus and the locus coeruleus that are the first to deteriorate in Alzheimer's disease. This could help us understand how to support and enhance memory and adaptive behavior, generally.