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).

Impairment of spatial performance by continuous intensive noise: A behavioral view.

“…Although further impairment was expected to result from increasing the noise intensity, performance in the MI group was better than in the LI group. This finding is consistent with Gheraat et al (2009) who found better results in the MI group than in the LI group in a Morris water maze task with intermittent noise. Another study found that children did not adapt to noise during a play period (i.e., retrieval; Hambrick-Dixon, 1986).…”

“…The importance of matching training and test conditions may be confirmed by the results of the former studies (Gheraat et al, 2009;Maes & de Groot, 2002). These findings may be expanded with the results of the present study.…”

“…However, effects of continuous high-intensity noise on the contextual transfer test after applying various intensities of noise during training have not been investigated. The importance of matching training and test conditions may be confirmed by the results of the former studies (Gheraat et al, 2009;Maes & de Groot, 2002). These findings may be expanded with the results of the present study.…”

“…High-intensity noise impairs visuomotor coordination in rats. In contrast, previous investigations did not find a significant decrease in performance on visible tests (Gheraat et al, 2009), tests of visual and intellectual function (Broadbent, 1979), or the separation of visual cues (Hambrick-Dixon, 1986) as a result of high-intensity noise. To learn the task adequately, the subject should be directed to rely on relevant visual cues rather than other sources of information.…”

“…The idea that various intensities of noise during acquisition may cause different performance levels has been debated. The noise intensities we used were representative of the intensities emitted from sporting matches that produce a wide range of noise (52-105 dbA) (Gheraat et al, 2009). …”