ONTOGENY OF ORIENTATION AND SPATIAL-LEARNING ON THE RADIAL MAZE IN MICE

The development of the orientation capacities of C57BL/6 mice has been studied on the radial maze in several procedures allowed to dissociat e the different types of cues used by the mouse for solving the task w ith two intersession delays (2 and 24 hr). The results of the first tw o studies show that performance is independent of intersession delay r egardless of the age of the subject. Mice as early as 23 days old obta in good performances when they can develop an algorithmic strategy or when they dispose of both proximal and distal cues during learning. At 37 days of age, however, mice can efficiently solve the radial maze t ask with distal cues alone. However, in the third experiment, 23-day-o ld mice were able to use distal cues for orientation at the end of the learning session if, at the onset, they also had access to proximal c ues. These results suggest that, on weaning, mice use several types of information for task performance and that, as they mature, they turn more often to distal cues for orientation. (C) 1995 John Wiley & Sons, Inc.