Ontogeny of orientation and spatial learning on the radial maze in mices

Abstract

The development of the orientation capacities of C57BL/6 mice has been studied on the radial maze in several procedures allowed to dissociate the different types of cues used by the mouse for solving the task with two intersession delays (2 and 24 hr). The results of the first two studies show that performance is independent of intersession delay regardless of the age of the subject. Mice as early as 23 days old obtain 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 task with distal cues alone. However, in the third experiment, 23-day-old 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 cues. 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.

Use of proximal and distal cues in place navigation by mice changes during ontogeny

“…However, while we have already demonstrated (Chapillon et al, 1995) that the working memory in 23-day-old mice is totally functional, other studies have also shown that in simple tasks (Nagy, Misanin, Newman, Olsen, & Hinderliter, & Sandmann, 1973) the working memory of mice is functional as early as 9 days of age. The working-memory versus reference-memory hypothesis thus seems irrelevant to explain the contradiction.…”

“…In this study, contrary to adults, the younger mice perform better with more compactly grouped sessions. The results of another experiment on a radial maze (Chapillon et al, 1995) have shown that, in this other type of spatial learning, younger mice also obtain better performances when the training sessions are closely grouped. Whatever the reason, the results shown by the younger mice on the Morris test demonstrate the excellent navigational capacity of very young animals.…”

“…As pointed out in the Introduction, proximal cues cannot be entirely eliminated from a radial maze. We have shown that if young mice have access to both proximal and distal cues during learning, they are capable of solving the task on a final session using distal cues only (Chapillon et al, 1995). Perhaps the younger mice have a greater tendency to spontaneously integrate proximal cues when they are available.…”

“…The results of the first two experiments, when compared with the results of radial maze experiments (Chapillon et al, 1995), have led us to examine the distractive (i.e., perturbing) role that nonpertinent proximal information could play in younger mice when trying to solve the task.…”

“…We recently studied the ontogeny of orientation and spatial learning abilities of C57BL/6 mice on the radial arm maze (Chapillon, Roullet, & Lassalle, 1995). We showed that it is only as of 37 days of age that mice can efficiently solve the radial arm maze task in a procedure in which only distal cues are relevant.…”