Rat hippocampal place cells exhibit little or no directional tuning when recorded in a high walled cylinder while the rat forages for randomly dispersed food (Muller et al., 1987; Muller et. al., 1994) .  On radial arm mazes and other tasks, however, place cells show a strong directional selectivity within their place fields (e.g., McNaughton et al., 1983a;  Muller et. al., 1994).  These experiments differ in a number of respects, including, the visual environment,  configuration of the traversable space, behavior (e.g., mean linear and angular velocities), and behavioral context (e.g., whether reinforcement is located in specific places rather than distributed randomly).  The contribution of these factors to place field directionality was systematically examined in the present study.  Cells were recorded from rats in either an enriched or a sparse visual environment, doing one of two behavioral tasks, and on a radial maze or on a platform.
    Place fields were smaller, more specific, and exhibited greater directional selectivity on radial mazes than on a circular platform, regardless of the visual environment.  On the open platform, place fields were more directional when the rat searched for food in a stereotypic and directed manner than when the search was for randomly scattered food.  Thus, it seems that place fields are more directional when the animal is planning or following a specific trajectory, and hence possibly related to the frame of reference attended to in navigation.
    The change in behavioral task was accompanied by a change in the location of the place fields in about one third of the cells.   Thus place cells encode not only information about a location in a given environment, but are affected by the significance of that location and/or the type of behavior needed for performance of the task.