Hippocampal hierarchical networks for space, time, and memory

The hippocampus is critically involved in both mapping space as well as the formation of memories for events. Here, we propose that common coding principles in the hippocampus enable spatial, temporal and episodic representations. We discuss recent studies employing novel cognitive tasks as well as newly developed representational analysis techniques which show that both spatial and mnemonic representations can be thought of as networks of interlinked elements, be it locations in space or events in memory. These mnemonic networks share certain characteristics, such as plasticity and hierarchical organisation, which enable structured representation of information while also allowing simultaneous assimilation of new elements. We conclude by outlining possibilities of how neural mechanisms underlying the formation of such networked representations can support the organisation of interlinked information beyond time and space