Spatial cognitive maps in animals: new hypotheses on their structure and neural mechanisms.

This article provides a hierarchical model of animal spatial cognitive maps. Such maps include both topological information, which affords loose, yet operational, representations of the connectivity of space and its overall arrangement, and metric information, which provides information about angles and distances. The model holds that maps can be initially described as a set of location-dependent reference frameworks providing directional information about other locations. The addition of an overall directional reference allows for the buildup of more complete (allocentric) representations. A survey of recent neurobiological data provides some hints about the brain structures involved in these processes and suggests that the hippocampal formation and the posterior parietal cortex would act differently by handling topological and metric information, respectively.