The Effect of Noise on Acquisition and Retention of a Spatial Memory Task in Equal and Unequal Context in Mature Male Rats

In this study, we examined the effects of noise on acquisition and retention of a spatial memory task in equal and unequal context in mature male rats. Subjects consisted of 22 mature male rats placed in 3 groups randomly (group A: 8 , group B: 7 and group C :7). The natural noise acquired in Azadi football stadium was used in surface of water maze system and was regulated in 2 intensities: High intensity (86 db) and Middle intensity (64 db) using SLM instrument. At first , we examined visual and memory systems of rats by visual and probe tests respectively. In the experiment, rats practiced a spatial memory task (water maze) in 4 trials , s blocks and 3 days of training program. Evaluation of acquisition was in the end of practice, and for retention was after 72 hours in equal and unequal situations. Then we recorded data about delay time and used ANOVA test for analyzing data in SPSS12. We showed a significant decrease in acquisition and retention among groups with an increase in intensity of noise. Also delay time increased with an increase in intensity of noise. Furthermore, the group trained in middle intensity had better delay time rather than the group trained in silence (group A) in transmission test with high intensity.