Whole-body exposure to 2.45 GHz electromagnetic fields does not alter radial-maze performance in rats

Mobile communication is based on utilization of electromagnetic fields (EMFs) in the frequency range of 0.3-300 GHz. Human and animal studies suggest that EMFs, which are in the 0.1 MHz-300 GHz range, might interfere with cognitive processes. In 1994, a report by Lai et al. [Bioelectromagnetics 15 (1994) 95-104] showed that whole-body exposure of rats to pulsed 2.45 GHz microwaves (2 micros pulse width, 500 pps, and specific absorption rate [SAR] 0.6 W/kg) for 45 min resulted in altered spatial working memory assessed in a 12-arm radial-maze task. Surprisingly, there has been only one attempt to replicate this experiment so far [Bioelectromagnetics 25 (2004) 49-57]; confirmation of the Lai et al. experiment failed. In the present study, rats were tested in a 12-arm radial-maze subsequently to a daily exposure to 2.45 GHz microwaves (2 micros pulse width, 500 pps, and SAR 0.6 W/kg) for 45 min. The performance of exposed rats was comparable to that found in sham-exposed or in naive rats (no contact with the exposure system). Regarding the methodological details provided by Lai et al. on their testing protocol, our results might suggest that the microwave-induced behavioral alterations measured by these authors might have had more to do with factors liable to performance bias than with spatial working memory per se.