Microwaves and Memory Loss.

New research published in the January 2000 issue of Bioelectro-magnetics suggests that exposure to microwaves may affect long-term memory function in rats. Henry Lai, a research professor in the bioengineering department at the University of Washington in Seattle, and Baoming Wang, a visiting professor from Tianjin Medical University in China, reported an alteration in long-term memory and learning in rats following exposure to microwaves.

In the study, one group of rats was exposed to pulsed microwaves for 1 hour at a frequency that Lai says is twice as high as cell phone emittances. A control group of rats was not exposed to microwaves. The researchers placed the rats in a tank of water clouded with powdered milk and and trained them to swim to a submerged platform that they couldn't see. The rats were then reintroduced to the pool at different locations to see if they could remember how to find the obscured platform.

"The microwave-exposed rats were much slower in finding the platform during the training session. They tended to spend more time attempting to climb the wall of the pool or swimming along the wall," Lai says. The difference in the rats' ability to find the platform was attributed to a deficit in long-term memory and learning ability rather than motivation or motor skills since the different groups' swimming speeds were the same.

After repeating this process several times, the researchers removed the platform and observed that rats in the control group spent most of their time swimming in the area where the missing platform had been located. The irradiated rats didn't show a tendency to search for the missing platform, and instead behaved more randomly. "They seemed to have trouble making a map in their heads, like the normal rats did, so they could recall where the platform was," said Lai in a November 1999 press release from the university. "Their spatial reference mapping or `place learning' strategies [using the relative position of various different cues as guides] seemed to be affected after their exposure."

Disturbance to the central nervous system may lessen the animals' learning capacity, Lai suggests, forcing them to resort to simpler learning strategies. However, critics of the study point out that there are other potential interpretations of the data. For example, effects such as those seen in both the training and testing phases of the experiment could be attributed to an emotional component in the rats.

Lai says that the frequency is similar to devices such as radar and other microwave equipment. The question remains whether or not this same type of long-term memory loss could affect humans exposed to similar microwaves. "It's difficult to extrapolate from these animal data whether or not the effect would be the same on humans." Lai says.