Variations in Radial Maze Performance under Different Levels of Food and Water Deprivation

Four groups of rats were tested on an eight-arm radial maze under a free-choice procedure. The subjects were maintained at either 80% or 100% of their preexperimental free-feeding weights through restricted access to either food or water. Water-deprived subjects received water in the maze; food-deprived subjects received food. Water-deprived subjects learned the task faster than food-deprived subjects. The four groups developed different response patterns. These were measured by the mean transition size, the average angular distance (in 45° units) between consecutively chosen arms. Rats foraging for food and water developed different search strategies, with water-deprived subjects exhibiting lower mean transition sizes. When the subjects were given three consecutive trials, 2 min apart, choice accuracy declined across trials, although performance on the last two trials improved across days. The groups' mean transition sizes remained different, and were constant over trials and days. Thus, the test procedures differentially affected choice accuracy and response patterning.