Effect of Visual Experience on Spatial Learning of Rats

Abstract

Background: Visual information acquired through observation plays a pivotal role in learning a movement pattern and motor control. Objectives: This study aimed to analyze the effect of visual deprivation on learning in rats. Methods: The study sample consisted of 12 male rats, divided into three groups. Group I consisted of four rats and was considered the control group. Transection of the two optic nerves was performed on rats of group II on the seventh day after birth and group III on the seventh week after birth to develop the early blind and late blind models, respectively. A T-shaped maze device was utilized to evaluate the learning behavior of rats. Rats of groups II and III were blinded by the optic nerve surgery. In total, 20 trials per day were conducted for nine consecutive days, in which the time and number of correct arm entries were recorded. The ANOVA and Kruskal-Wallis tests were employed to analyze the results in SPSS software (version 16.0). A p-value of less than 0.05 was considered statistically significant. Results: There was a significant difference between the three groups regarding the number of correct arm entries on days one, three, and seven (P<0.05). There was also a significant difference between the three groups regarding how long it took them to enter the target box on days two and three (P<0.05). Group III had a lower number of entries to the target box and it took them a significantly longer time to enter the target box, compared to the other groups. Conclusion: According to the results, visual deprivation may affect the learning of rats during the early days; however, their learning levels increased over the following days. Moreover, the early blinded rats had a higher level of learning than the lately blinded adult rats and the same level of learning as that of the sighted adult rats.