Summary

neural systems are known to encode self-location in the brain: place cells in the hippocampus encode unique locations in unique environments, whereas grid cells, border cells and head-direction cells in the parahippocampal cortex provide a universal metric for mapping positions and directions in all environments. These systems have traditionally been studied in very simple environments; however, natural environments are compartmentalized, nested and variable in time. Recent studies indicate that hippocampal and entorhinal spatial maps reflect this complexity. The maps fragment into interconnected, rapidly changing and tightly coordinated submaps. Plurality, fast dynamics and dynamic grouping are optimal for a brain system thought to exploit large pools of stored infor-mation to guide behavior on a second-by-second time frame in the animal’s natural habitat. SPATIAL MAPS IN THE BRAIN More than 60 years ago, Tolman proposed that animals form internal cognitive maps of their spatial environment [1]. Cognitive maps were thought to represent a mental knowl-edge base in which information is stored according to its relationship to locations in the 42 4. A MANIFOLD OF SPATIAL MAPS IN THE BRAIN environment. Following the discovery of place cells two decades later [2–4], O’Keefe an