Is the hippocampus of the rat part of a specialized navigational system?

The spatial mapping theory of hippocampal function proposes that the rat hi ppocampus is specialized for navigational computations, computations that a llow the animal to solve difficult spatial problems. In this paper, we revi ew evidence obtained by recording place cells and other "spatially tuned" c ells from freely moving rats. Our main conclusion is that the nature of the signals carried by these cells and the ways in which the signals transform after changing the environment imply that the hippocampus and associated s tructures are able to represent aspects of the geometry of the environment. (C) 1999 Wiley-Liss, Inc.