The effects of high-frequency electromagnetic fields emitted by mobile phones on humans have been hotly debated for years. In a new study, neuroscientists from Ruhr-Universitaet-Bochum (RUB) in Germany have shed light on this question. For the first time, they provide evidence that extremely high-powered electromagnetic fields can influence learning processes on the synaptic level within the brain, independent from other factors such as stress.
High-frequency electromagnetic fields (HEFs) are not only used in mobile phones, but also in a variety of other communication systems like radio, television or cordless telephone sets. Mobile phones of the so-called third generation utilize the UMTS technology (Universal Mobile Communication System) with a frequency of 1200 MHz and a relatively weak operating range (3.8-4.8 V/m). With increasing power, electromagnetic fields (EMFs) are able to elicit local warming of body tissues, being also described as a "thermal effect." Reportedly, mobile phones can cause local warming of the brain by less than 0.1°C. The effect on function and structure of the brain during long term use of mobile phones (e.g. > 30 min) remains unexplained until now.
… and might influence cellular activity
Furthermore, findings regarding the non-thermal effects of mobile phone emitted EMFs are unclear and contradictory. These comprise, for instance, an increase in permeability and fluidity of cellular membranes, which can be implicated in changes in ion-channel integration and metabolism, even without a detectable change in temperature. This may impair synaptic learning processes in the brain. Until now, experiments could not sufficiently answer the question of whether these effects are derived from non-thermal HEFs or from stress, as it can be induced by handling of the experimental animal (e.g. placing a rat into an unknown environment).
Stress or non-thermal EMF effect -- Scientists find out for the first time
To investigate this question, a new study was performed by scientists of the Department of Neuroanatomy and Molecular Brain Research (Professor Dr. med. Rolf Dermietzel) in cooperation with the Chair of Electromagnetic Theory of the University of Wuppertal. For the experiment, rats were placed into differently powered non-thermal HEFs in the UMTS operating range. Synaptic learning and memory formation were analysed by electrophysiological methods. Furthermore, all animals were tested for stress hormone release immediately following the HEF exposure.
The results: Although there was daily training and effortless contact to the exposure environment, increases in blood derived stress hormone levels could be detected for all exposed groups. The stress clearly influences learning and memory formation on the synaptic level in the rat brain. High-powered EMFs (SAR 10 W/kg) also have a significant effect on learning and memory formation. In contrast to this, weak EMFs (SAR 0 and 2 W/kg) lead to no detectable changes or impairments.
"It can be demonstrated that neuronal mechanisms of synaptic learning can serve as a target for high powered EMFs," says Nora Prochnow.