Mind the gap: binding experiences across space and time in the human hippocampus.

A fundamental goal in memory research is to understand what class of learning problem the hippocampus is uniquely designed to solve. While much controversy surrounds the particular types of memories the hippocampus is thought to support, one hypothesized function possibly linking divergent frameworks is the capacity to bind mnemonic representations across spatial and temporal gaps in our experience. In our current functional magnetic resonance imaging (fMRI) study, we systematically controlled the extent to which a target and an event detail have to be integrated across spatiotemporal discontiguities during associative memory formation. Although the encoding task, the type of association, and subsequent memory performance were held constant, engagement of the hippocampus during successful associative binding was directly modulated by increases in spatial and temporal discontiguities across episodic elements. These results suggest that a core mnemonic function of the hippocampus is to bridge representational gaps in our experience.