The effect of disrupting configural information on rats' performance in the Morris water maze

Many experiments on spatial navigation suggest that a rat uses the configuration of extra-maze landmarks to guide its choice of arm or location to visit. In the present study, based on Chamizo Rodríguez, Espinet, and Mackintosh's (2012) navigation paradigm, we conducted a series of experiments in which we focused on how changes to the configuration of stimuli surrounding the maze, implemented by transposing the location of both near and far landmarks, significantly affected rats' performance (Experiment1, Test Phase 1). Subsequent tests demonstrated that it was the near landmarks that played the major role in this navigation task (Experiment 1, Test Phases 2 and 3). Experiment 2 provided evidence for a novel type of inversion effect in the water maze, by showing that rotation by 180° of the location of one set of landmarks relative to a directional cue also strongly affected performance.