Route and survey processing of topographical memory during navigation.

We investigated the characteristics of route and survey processing of a unique complex virtual environment both at the behavioral and brain levels. Prior to fMRI scanning, participants were trained to follow a route and to learn the spatial relationships between several places, acquiring both route and survey knowledge from a ground-level perspective. During scanning, snapshots of the environment were presented, and participants were required to either indicate the direction to take to follow the route (route task), or to locate unseen targets (survey task). Data suggest that route and survey processing are mainly supported by a common occipito-fronto-parieto-temporal neural network. Our results are consistent with those gathered in studies concerning the neural bases of route versus survey knowledge acquired either from different perspectives or in different environments. However, rather than arguing for a clear distinction between route and survey processing, "mixed" strategies are likely to be involved when both types of encoding take place in the same environment.