Impairment of Spatial Performance by Environmental Noise

Abstract

We examined the effects of noise on acquisition and retention of the spatial memory task in equal and unequal context in adult male rats. The natural noise in Azadi football stadium was recorded and measured by sound level meter instrument and set in high (HI), moderate (MI), and low (LI) intensities, 86, 64, and 47 decibels A (dbA), respectively. Rats were trained in Morris water maze (MWM) for 3-consecutive-day program and at day 4 visible and probe tests were done under one of the above noise intensities. The retention was evaluated at day 7 on the basis of equal and unequal noise exposure situation. Escape latency, traveled distance, and swimming speed were recorded and used for subsequent analysis. Our results showed significant increases in the escape latency and traveled distance by increasing the noise intensity during acquisition period, and also retention test in equal noise situation. Furthermore, retention test in the group that was under HI noise during both training period and retention test escape latency and traveled distance compared to the groups which was under HI noise during training period and LI or MI noise during retention test (HI-LI or HI-MI).