Change in Visual Experience Impairs Rat's Spatial Learning in Morris Water Maze

Proper structure and function of mammal’s central nervous system (CNS) is based on inborn neuronal function. Sensory experience-based development deeply affects these processes in the critical period. The aim of this study was to investigate the effects of change in visual experience in critical period of brain development on rat’s spatial learning and memory using Morris water maze (MWM). This experimental study was carried out on 30 Wistar male rats at 45 days old randomly distributed in 3 groups (n=10 for each group); the CO (Control) group was in 12 h light/12 h dark cycle through birth to the end of the study; the LR (Light Reared) group was in complete light (24 hours) and the DR (Dark Reared) group was in complete darkness. Using MWM, the animals learned to find a hidden platform for 4 trials/day at 5 days. After removing platform, spatial memory was tested at day 5 in one trial. The spent time and distance in the correct quadrant measured and analyzed by repeated measure ANOVA test. In the learning stage, the CO rats spent less time and distance to find the hidden platform than the other groups (P < 0.0001). There was no difference between all groups in probe trial. Change in visual experience impairs rat's spatial learning and spatial memory formation would not been influenced.