SCIPRESS FORMA
Forma, Vol. 11 (No. 2), pp. 83-101, 1996
Original Paper

Modelling Navigation by the Rat Hippocampus

Neil Burgess, James G. Donnett and John O'Keefe

Dept. of Anatomy, University College London, Gower St., London, WC1E 6BT

(Received October 25, 1995; Accepted January 10, 1996)

Keywords: Navigation, Spatial Cognition, Hippocampus

Abstract. The spatial and temporal correlates of neuronal firing in and around the rat hippocampus are reviewed with respect to their computational role in navigation. The regular organisation of this brain formation and its putative role in learning and memory have made it highly attractive as a basis for studying relationships between structure and function in the mammalian brain. In particular, we propose a model of hippocampal function in which 'place cells' and 'head-direction cells' serve to construct a set of 'population vectors' representing the instantaneous direction and distance of the rat from previously encountered goal locations in the environment. Goal-independent 'latent learning' is present in the model during the construction of place cells' responses to environmental cues. The population vector representation is created by one-shot Hebbian increment of synaptic connections when the rat is at a goal location. This process exploits the putative phase coding of place cell firing with respect to the theta rhythm of the hippocampal EEG. The simulated system requires only brief exploration and can return to a goal location after encountering it only once.