Neil Burgess, John O'Keefe, Michael Recce
A model of the hippocampus as a central element in rat naviga(cid:173) tion is presented. Simulations show both the behaviour of single cells and the resultant navigation of the rat. These are compared with single unit recordings and behavioural data. The firing of CAl place cells is simulated as the (artificial) rat moves in an en(cid:173) vironment. This is the input for a neuronal network whose output, at each theta (0) cycle, is the next direction of travel for the rat. Cells are characterised by the number of spikes fired and the time of firing with respect to hippocampal 0 rhythm. 'Learning' occurs in 'on-off' synapses that are switched on by simultaneous pre- and post-synaptic activity. The simulated rat navigates successfully to goals encountered one or more times during exploration in open fields. One minute of random exploration of a 1m2 environment allows navigation to a newly-presented goal from novel starting po(cid:173) sitions. A limited number of obstacles can be successfully avoided.