The effects of the weekend phase delay like shifts on spatial learning performances of the Wistar rats: the sex and generation differences

Abstract

Many people regularly wake up early in the morning on week days; however, during weekends, they stay awake late into the night and wake up late, thus representing a phase delay in their locomotor activity and sleeping pattern. We suggest that these phase delays on weekends may affect the spatial memory performance at the first couple of days in the following week. In the present study, we aimed to investigate the effects of the weekend phase delays on spatial memory performance of the Wistar albino rats at the beginning of the coming week by using Morris water maze. Control and phase delay groups were performed for both juvenile and adult rats in males and females. After eight weeks of the experimental phase delays, Morris water maze experiments were performed. Locomotor activity rhythms of the rats were also examined. The adult rats showed better learning performances in the total distance travelled and latency than the juvenile ones. However, juvenile rats entered and spent more time in the correct quadrant than adult ones. Phase delays reduced the velocity of the rats. The interaction effects among the phase delays, generation and sex were also significant. The findings of the present study showed that the phase delays at the weekends as well as their interaction with sex and generation are important on the learning performances of the Wistar albino rats.

Keywords:

• weekend phase delay
• learning and memory
• Morris water maze
• rat