The social hippocampus.

The concept of cognitive map has been proposed as a way to organize our experiences and guide behavior across all domains of cognition. The hippocampus has been identified as the neural substrate supporting cognitive maps for navigating physical space. Recent evidence is broadening the role of the hippocampus into mapping other manner of spaces. Here we focus on the case of social space as a candidate for hippocampal representation because it combines multiple continuous dimensions and requires dynamic navigation through social contexts. We present evidence for the role of the hippocampus in (1) supporting social memory, (2) representing different dimensions of social space, (3) tracking dynamic social behavior, (4) maintaining a flexible map allowing adaptation to new social contexts, and (5) maladaptive social behavior across psychiatric disorders. To do so, we explore evidence across species including birds, rodents, nonhuman primates and humans, indicating hippocampal involvement in a range of social processes. Review of previous findings in a manner predicted by the cognitive map supports the existence of systematic mapping of social space by the hippocampus. Evidence for hippocampal social maps complements findings from other abstract domains, such as auditory, temporal and conceptual, allowing successful navigation through many domains of everyday life.