Analysis of spatial orientation strategies of male and female Wistar rats in a Morris water escape task

Abstract

In the present study we investigated spatial navigation in male and female Wistar rats in the Morris water escape task. Rats were subjected to procedures which required the use of a place (PLACE), cue (CUE) and egocentric (EGO) response to learn the task efficiently. In a first experiment rats were successively tested in the PLACE, CUE and EGO condition and in a second experiment the order of tasks was reversed. The first experiment showed that female rats swam longer distances and took more time to find the platform in the PLACE task. Further, the female rats spent less time near the previous platform position than the male rats during probe trial. No sex difference was found in the CUE and EGO task. In the second experiment, the female rats took longer to find the platform than the male rats in the EGO task. In the CUE and PLACE task no differences between the sexes was found during acquisition. However, the male rats spent more time near the previous platform position than the female rats during the probe trial of the PLACE task. On basis of present data it is concluded that the use of a PLACE-based strategy is better in male Wistar rats. CUE learning is not sex-dependent. The ability to use EGO strategies appears not to be different between male and female Wistar rats, but appears dependent on pre-exposure to the task.