Spatial learning and memory in the radial maze: a longitudinal study in rats from 4 to 25 months of age.

This longitudinal study was designed to investigate whether previous experience may influence performances and strategies of rats tested in the radial maze without external cues when aged 4, 13, and 25 months. Their performances and strategies were compared with those of another group of rats tested only when aged 25 months. Expert old animals showed a good retention of previous experiences, whereas age-matched nonexpert animals exhibited some acquisition deficits. On the contrary, in the course of aging, the animals kept modifying their strategies independently of experience. In summary, we can conclude that previous experience is likely to influence performances of the aged rat but not the strategies adopted which are strictly age-dependent and independent of acquired experience.