Behavior on the water maze platform: Relationship to learning and open field exploration in aged and adult rats

In the present study we examined whether age-related deficits in the water maze could be accounted for by changes in the behavior on the platform, and whether platform behavior represents some form of exploration, akin to that seen in the open field. Twenty-seven aged and 8 adult rats (26 and 3 months old Wistar rats, respectively) were tested in an empty open field and spatial object exploration task, followed by 9 days of escape learning in a water maze. The aged as compared to the adults exhibited lower levels of open field activity and were deficient in the object displacement task. Escape deficits in the water maze and reduced activity levels on the platform were also found. In the aged, water maze performance was correlated with behavior on the platform, including quiescence, orienting-like activity and turning behavior, a form of axial rotation. In both age groups, turning behavior was also correlated with exploratory activity in the open field. In conclusion, the results support the hypothesis that age-related impairments in the water maze relate to changes in platform behavior, which, in turn, might reflect exploratory activity.