Wang B, Lai H (2000)
Rats were trained in six sessions to locate a submerged platform in a circular water maze. The animals were exposed to microwaves or sham-exposed for one hour immediately before each session. The RF radiation used was pulsed 2450 MHz at a spatially averaged power density of 2mW/cm² (average whole body SAR 1.2 W/kg). In addition to the 11 exposed and 11 sham-exposed animals, 12 control rats were included in the experiment. These rats were housed in cages in the laboratory and subjected to the same maze-running procedure as the others.
In the maze-running the animals were randomly released into the water from the east, west, south and north sides of the pool. Hence there were four trials per training session. The escape time - the time between release in the water to landing on the platform - was measured by a stop-watch. In addition, one hour after the last training session, each animal was given a probe trial, in which the platform was removed from the maze and the animal was released from the south point and allowed to swim in the pool for 60 seconds. The performance in the maze was videotaped for later analysis, which was done by an experimenter unaware of the exposure status of the animal.
Microwave-exposed animals were slower than sham-exposed and cage control rats in learning to locate the platform. During the probe trial, the microwave-exposed animals spent significantly less time in the quadrant that had contained the platform, and their swim patterns were different than the other animals. The authors state that the results showed "that acute exposure to pulsed microwaves caused a deficit in spatial reference memory in the rat".