The Effect of 12 Hz Extremely Low-frequency Electromagnetic Field on Visual Memory of Male Macaque Monkeys
Authors:   Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran., Kazemi Masoomeh , Aliyari Hamed ,   Center for Human-Engaged Computing, Kochi University of Technology, Kochi, Japan., Tekieh Elaheh ,   Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran., Tavakoli Hassan ,   Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran., Golabi Sahar ,   Department of Medical Physiology, School of Medicine, Abadan University of Medical Sciences, Abadan, Iran., Sahraei Hedayat ,   Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran., Hossein Meftahi Gholam ,   Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran., Salehi Maryam ,   Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran., Saberi Mehdi ,   Department of Pharmacology and Toxicology, Faculty of Pharmacy, Baqiyatallah University of Medical Sciences, Tehran, Iran.
Published: June 2021

Introduction: Today, humans live in a world surrounded by electromagnetic fields. Numerous studies have been conducted to discover the biological, physiological, and behavioral effects of electromagnetic fields on humans and animals. Given the biological similarities between monkeys and humans, The present research aimed to examine Visual Memory (VM), hormonal, genomic, and anatomic changes, in the male rhesus macaques exposed to an Extremely Low-Frequency Magnetic Field (ELF-MF). Methods: Four male rhesus macaques (Macaca mulatta) were used. For the behavioral tests, the animals should be fasting for 17 hours. For the tests such as visual memory, the animal’s cooperation was necessary. Using the radiation protocol, we exposed two monkeys to a 12-Hz electromagnetic field with a magnitude of 0.7 µT (electromagnetic radiation) four hours a day for a month. Before and after the exposure, a visual memory test was conducted using a coated device (visible reward) on a movable stand. Ten milliliters of blood was obtained from the femoral artery of each monkey, and half of it was used to examine cortisol serum levels using the MyBioSource kit (made in the USA). The other half of the blood was used to extract lymphocytes for assaying expressions of Glucocorticoid Receptor (GR) genes before and after radiation using the PCR method. Anatomic studies of the amygdala were carried out based on pre- and post-radiation Magnetic Resonance Imaging (MRI). Results: Research results indicated that visual memory in male primates increased significantly after exposure to the 12-Hz frequency. Hormonal analysis at the 12-Hz frequency showed a decrease in cortisol serum levels. However, visual memory and serum cortisol levels did not change considerably in male primates in the control group. There was no considerable amygdala volumetric difference after exposure to the 12-Hz frequency. The expression of the GR genes decreased in the 12-Hz group compared to the control group. Conclusion: In short, these results indicated that ELF might benefit memory enhancement because exposure to the 12-HZ ELF can enhance visual memory. This outcome may be due to a decrease in plasma cortisol and or expression of GR genes. Moreover, direct amygdala involvement in this regard cannot be recommended.