Hippocampal activity during consolidation of complex spatial representations

In the real world, we often need to understand complex spatial relationships and integrate existing knowledge. For example, when we learn a new route between familiar places, we need to integrate the new knowledge and create a new cognitive map of the space. Since the hippocampus is a key structure for episodic memory formation and spatial navigation, we examined the activity of hippocampal CA1 neurons when combining simple maps of a complex space. An experiment was designed, consisting of several phases, in each of which the rat was introduced to four different arms of the maze. In the first phase, the rat explored pairs of non-overlapping arms. In the second, it explored a combination of previously known arms, and in the third, all the arms of the labyrinth. During these visits, the rat had to understand the spatial relationships between the different combinations and create a complete map of the space. My results suggest that the rat was unable to understand the relationship between the independent arms before visiting the entire maze. While exploring the entire labyrinth, a completely new map for the maze was created, and there were also changes in the activity of neurons encoding already known combinations of arms. Keywords: hippocampus, sleep, remapping, place cell