MEMORY FOR PLACES - A NAVIGATIONAL MODEL IN SUPPORT OF MARRS THEORY OF HIPPOCAMPAL FUNCTION

In this report we describe a model that applies Marr's theory of hippo campal function to the problem of map-based navigation. Like many othe rs we attribute a spatial memory function to the hippocampus, but we s uggest that the additional functional components required for map-base d navigation are located elsewhere in the brain. One of the key functi onal components in this model is an egocentric map of space, located i n the neocortex, that is continuously updated using ideothetic (self-m otion) information. The hippocampus stores snapshots of this egocentri c map. The modeled activity pattern of head direction cells is used to set the best egocentric map rotation to match the snapshots stored in the hippocampus, resulting in place cells with a nondirectional firin g pattern. We describe an evaluation of this model using a mobile robo t and demonstrate that with this model the robot can recognize an envi ronment and find a hidden goal. This model is discussed in the context of prior experiments that were designed to discover the map-based spa tial processing of animals. We also predict the results of further exp eriments. (C) 1997 Wiley-Liss, Inc.