Using proximal and distal cues in the water maze: Strategies and neural bases

E. Save, C. Parron and B. Poucet

Laboratory of Neurobiology and Cognition, UMR 6155 CNRS, Université Aix-MarseilleI, Marseille, France

The importance of distal extramaze cues in guiding place navigation has been demonstrated in the water maze. However, a number of behavioral and electrophysiological studies indicates that proximal intramaze cues may also serve as place cues. Recently, we have provided evidence that, although distal and proximal cues both support mapping strategies, processing these two kinds of cues involves activation of different neural circuits. Contribution of the hippocampus, parietal cortex, and entorhinal cortex to distal and proximal cue processing was examined by training lesioned rats in two versions of the water maze place navigation task. In the distal condition, rats had to locate a submerged platform by relying on extramaze cues and in the proximal condition by relying on objects directly placed in the pool. Path analysis was made by a Videotrack 2.6 tracking system (ViewPoint, Champagne-au-Mont-D’or, France). The results suggest that the processing of distal cues requires the hippocampus and the entorhinal cortex whereas the processing of proximal landmarks involves the hippocampus and the parietal cortex. This is consistent with the idea of a dual processing system whose activation depends on the distance of landmarks. These two systems are mediated by distinct cortical areas but eventually converge on the hippocampus which is assumed to form an integrated spatial map.

Paper presented at Measuring Behavior 2005 , 5^th International Conference on Methods and Techniques in Behavioral Research, 30 August - 2 September 2005, Wageningen, The Netherlands.

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