Journal of Paramedical Sciences (JPS) Summer 2012 Vol.3, No.3 ISSN 2008-4978 30 Long-term exposure to low frequency electro-magnetic fields of 50- and 217-Hz leads to learning and memory deficits in mice Elaheh Nooshinfar 1,2,* , Mostafa Rezaei-Tavirani 3 , Soheila Khodakarim 3 1 Physiology Department, Faculty of paramedical sciences, Shahid Beheshti university of medical sciences, Tehran, Iran 2 Cancer Research Center, Shahid Beheshti university of medical sciences, Tehran, Iran 3 Proteomics Research Center, Faculty of paramedical sciences, Shahid Beheshti university of medical sciences, Tehran, Iran *Corresponding Author: email address: e_nooshinfar@yahoo.com (E. Nooshinfar) ABSTRACT Electromagnetic field (EMF) radiation affects cellular and brain chemistry and function, resulting in deleterious effects such as free radicals formation, impaired DNA repair, reduced melatonin and blood brain barrier protection, and defects on learning and memory and other higher brain functions. In this paper the effects of low frequency EMF of 50- and 217 Hz, ranges often associated with common electronic devices such as televisions and cell phones were examined on learning and memory in adult male mice. Five groups (n=10 mice/group) of mice (1 control and 4 experimental) were initially trained for the passive avoidance (PA) test. They were then placed in devices creating EMF radiation with varying intensities (0.5 to 2 milli- Tesla, mT) and frequencies (50- and 217-Hz) for 2-weeks (16 hrs/day). Control mice received no radiation. Learning and memory was tested by the PA test and evaluated based on the following parameters: mean step through latency (STL), number of crossing (Cr#) and time in dark compartment (TDC). Results showed significant deficiencies in learning and memory in the EM-exposed mice compared to controls: mean STL decreased significantly (p<0.001) in the 50 Hz group (1 and 1.5 mT intensities). In the 217 Hz group, STL also decreased in the 0.5 and 2 mT groups (p< 0.05). There was a notable increase in mean Cr# for both groups and TDC for 50 Hz group. Results confirm that long-term exposure to EMF radiation of 50 and 217 Hz, imparts significant harmful changes on memory and learning, reiterating the need for preventive measures against such exposures. Keywords: memory; low frequency electromagnetic fields; passive avoidance learning INTRODUCTION Memory and learning are of great importance in human life and activities. Many factors are known to have positive and negative effects on memory formation and recall. Earlier findings demonstrated that electromagnetic fields (EMF) disturb spatial orientation and recognition in experimental animals [1, 2, 3]. These studies were confirmed by more recent studies that illustrate deficits in other types of learning and memory [4, 5, 6] including concomitant alterations in hippocampal CA3 region [5]. Other investigations have either not found deficits in cognitive functions or reported positive and useful effects of low frequency, short-term EMF on memory in some animal species [7, 8]. Thus effects of low frequency (0-300 Hz) EMF on cognitive processes have either not been adequately studied or are controversial at best. Given the multitude of electronic devices used in everyday modern life, especially the marked overuse of cell phones along with the reported possible harmful effects of EMF radiation on body tissues and health, further study of the biologic, neurobiological and other effects on health appears to be critical and necessary to investigate. Electronic devices, electric power-lines and cell phones used in human environments produce EMF of 50 and 217 Hz. The aim of this paper is to artificially generate the latter EMF radiation in varying intensities of 0.5-2 milliTesla (mT), in order to investigate the effects of long-term