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Abtin S, Seyedaghamiri F, Aalidaeijavadi Z, Farrokhi AM, Moshrefi F, Ziveh T, Zibaii MI, Aliakbarian H, Rezaei-Tavirani M, Haghparast A. A review on the consequences of molecular and genomic alterations following exposure to electromagnetic fields: Remodeling of neuronal network and cognitive changes. Brain Res Bull 2024; 217:111090. [PMID: 39349259 DOI: 10.1016/j.brainresbull.2024.111090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2024] [Revised: 09/10/2024] [Accepted: 09/26/2024] [Indexed: 10/02/2024]
Abstract
The use of electromagnetic fields (EMFs) is essential in daily life. Since 1970, concerns have grown about potential health hazards from EMF. Exposure to EMF can stimulate nerves and affect the central nervous system, leading to neurological and cognitive changes. However, current research results are often vague and contradictory. These effects include changes in memory and learning through changes in neuronal plasticity in the hippocampus, synapses and hippocampal neuritis, and changes in metabolism and neurotransmitter levels. Prenatal exposure to EMFs has negative effects on memory and learning, as well as changes in hippocampal neuron density and histomorphology of hippocampus. EMF exposure also affects the structure and function of glial cells, affecting gate dynamics, ion conduction, membrane concentration, and protein expression. EMF exposure affects gene expression and may change epigenetic regulation through effects on DNA methylation, histone modification, and microRNA biogenesis, and potentially leading to biological changes. Therefore, exposure to EMFs possibly leads to changes in cellular and molecular mechanisms in central nervous system and alter cognitive function.
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Affiliation(s)
- Shima Abtin
- Neuroscience Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Fatemehsadat Seyedaghamiri
- Neuroscience Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Zahra Aalidaeijavadi
- Neuroscience Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Amir Mohammad Farrokhi
- Neuroscience Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Fazel Moshrefi
- Neuroscience Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Tayebeh Ziveh
- Laboratory of Biophysics and Molecular Biology, Departments of Biophysics, Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
| | | | - Hadi Aliakbarian
- Faculty of Electrical Engineering, KN Toosi University of Technology, Tehran, Iran
| | | | - Abbas Haghparast
- Neuroscience Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran; School of Cognitive Sciences, Institute for Research in Fundamental Sciences, Tehran, Iran; Department of Basic Sciences, Iranian Academy of Medical Sciences, Tehran, Iran.
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Bontempi B, Lévêque P, Dubreuil D, Jay TM, Edeline JM. Effects of Head-Only Exposure to 900 MHz GSM Electromagnetic Fields in Rats: Changes in Neuronal Activity as Revealed by c-Fos Imaging without Concomitant Cognitive Impairments. Biomedicines 2024; 12:1954. [PMID: 39335468 PMCID: PMC11428239 DOI: 10.3390/biomedicines12091954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2024] [Revised: 08/07/2024] [Accepted: 08/22/2024] [Indexed: 09/30/2024] Open
Abstract
Over the last two decades, animal models have been used to evaluate the physiological and cognitive effects of mobile phone exposure. Here, we used a head-only exposure system in rats to determine whether exposure to 900 MHz GSM electromagnetic fields (EMFs) induces regional changes in neuronal activation as revealed by c-Fos imaging. In a first study, rats were exposed for 2 h to brain average specific absorption rates (BASARs) ranging from 0.5 to 6 W/kg. Changes in neuronal activation were found to be dose-dependent, with significant increases in c-Fos expression occurring at BASAR of 1 W/kg in prelimbic, infralimbic, frontal, and cingulate cortices. In a second study, rats were submitted to either a spatial working memory (WM) task in a radial maze or a spatial reference memory (RM) task in an open field arena. Exposures (45 min) were conducted before each daily training session (BASARs of 1 and 3.5 W/kg). Control groups included sham-exposed and control cage animals. In both tasks, behavioral performance evolved similarly in the four groups over testing days. However, c-Fos staining was significantly reduced in cortical areas (prelimbic, infralimbic, frontal, cingulate, and visual cortices) and in the hippocampus of animals engaged in the WM task (BASARs of 1 and 3.5 W/kg). In the RM task, EMF exposure-induced decreases were limited to temporal and visual cortices (BASAR of 1 W/kg). These results demonstrate that both acute and subchronic exposures to 900 MHz EMFs can produce region-specific changes in brain activity patterns, which are, however, insufficient to induce detectable cognitive deficits in the behavioral paradigms used here.
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Affiliation(s)
- Bruno Bontempi
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, CNRS UMR 5287, Université de Bordeaux et Ecole Pratique des Hautes Etudes, 33000 Bordeaux, France
| | - Philippe Lévêque
- XLIM, CNRS UMR 6172, Université de Limoges, 87060 Limoges, France
| | - Diane Dubreuil
- Institut des Neurosciences Paris-Saclay (NeuroPSI), Université Paris-Saclay, CNRS, CEA Paris-Saclay, bât 151, 91400 Saclay, France
| | - Thérèse M Jay
- Institut de Psychiatrie et Neurosciences de Paris, UMR_S 1266 INSERM, Université Paris Cité, 75014 Paris, France
| | - Jean-Marc Edeline
- Institut des Neurosciences Paris-Saclay (NeuroPSI), Université Paris-Saclay, CNRS, CEA Paris-Saclay, bât 151, 91400 Saclay, France
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Navarro EA, Navarro-Modesto E. A mathematical model and experimental procedure to analyze the cognitive effects of audio frequency magnetic fields. Front Hum Neurosci 2023; 17:1135511. [PMID: 37250701 PMCID: PMC10218710 DOI: 10.3389/fnhum.2023.1135511] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 04/13/2023] [Indexed: 05/31/2023] Open
Abstract
Audio frequency magnetic fields (20 Hz-20 kHz) are magnetic fields in extremely low frequency-very low frequency (ELF-VLF) bands that are present near audio equipment and acoustic transducers. These devices transform and operate the electrical signal from the recordings or other devices into acoustic and audio signals. The cognitive influence of sound and noise has been widely studied and recognized since the times of ancient Rome; however, the cognitive effects of the magnetic fields of these frequencies have not been studied. Due to the extensive use of audio devices that use this type of transducer near the temporal-parietal area, we believe that it is of interest to study their impact on short-term memory or working memory (WM) and to analyze their potential as they operate as a transcranial magnetic stimulation. In this study, a mathematical model and an experimental tool are introduced to analyze memory performance. The model dissociates the reaction time of a cognitive task. We analyze the model in data from a group of 65 young, healthy subjects. WM is assessed in our experimental setup by means of the Sternberg test (ST), whereby during the ST, one subgroup was exposed to an audio frequency magnetic stimulus, and the other subgroup received a sham stimulus. The magnetic stimulus was ~0.1 μT and was applied to both sides of the head at the frontal cortex near the temporal-parietal area, which is where WM is expected to be located. The ST records reaction times when determining whether an object displayed on the computer screen is one of the objects to be remembered. The results are analyzed within the mathematical model and changes are observed, including the deterioration of WM, which could affect 32% of its operability.
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Affiliation(s)
- Enrique A. Navarro
- Departament de Informàtica, ETSE, Universitat de València, València, Spain
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4
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Lai H. Neurological effects of static and extremely-low frequency electromagnetic fields. Electromagn Biol Med 2022; 41:201-221. [DOI: 10.1080/15368378.2022.2064489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Henry Lai
- Department of Bioengineering, University of Washington, Seattle, WA, USA
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5
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Moretti J, Rodger J. A little goes a long way: Neurobiological effects of low intensity rTMS and implications for mechanisms of rTMS. CURRENT RESEARCH IN NEUROBIOLOGY 2022; 3:100033. [PMID: 36685761 PMCID: PMC9846462 DOI: 10.1016/j.crneur.2022.100033] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Revised: 01/26/2022] [Accepted: 02/15/2022] [Indexed: 01/25/2023] Open
Abstract
Repetitive transcranial magnetic stimulation (rTMS) is a widespread technique in neuroscience and medicine, however its mechanisms are not well known. In this review, we consider intensity as a key therapeutic parameter of rTMS, and review the studies that have examined the biological effects of rTMS using magnetic fields that are orders of magnitude lower that those currently used in the clinic. We discuss how extensive characterisation of "low intensity" rTMS has set the stage for translation of new rTMS parameters from a mechanistic evidence base, with potential for innovative and effective therapeutic applications. Low-intensity rTMS demonstrates neurobiological effects across healthy and disease models, which include depression, injury and regeneration, abnormal circuit organisation, tinnitus etc. Various short and long-term changes to metabolism, neurotransmitter release, functional connectivity, genetic changes, cell survival and behaviour have been investigated and we summarise these key changes and the possible mechanisms behind them. Mechanisms at genetic, molecular, cellular and system levels have been identified with evidence that low-intensity rTMS and potentially rTMS in general acts through several key pathways to induce changes in the brain with modulation of internal calcium signalling identified as a major mechanism. We discuss the role that preclinical models can play to inform current clinical research as well as uncover new pathways for investigation.
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Affiliation(s)
- Jessica Moretti
- School of Biological Sciences, The University of Western Australia, Perth, WA, Australia,Perron Institute for Neurological and Translational Science, Perth, WA, Australia
| | - Jennifer Rodger
- School of Biological Sciences, The University of Western Australia, Perth, WA, Australia,Perron Institute for Neurological and Translational Science, Perth, WA, Australia,Corresponding author. School of Biological Sciences M317, The University of Western Australia, 35 Stirling Highway, Crawley WA, 6009, Australia.
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Zheng Y, Zhao L, Dong L, Tian C, Xia P, Jin Z. The Time-Dependence of Three Different Modes of ELF-EMF Stimulation on LTP at Schaffer Collateral-CA1 Synapses. Bioelectromagnetics 2021; 42:538-549. [PMID: 34449888 DOI: 10.1002/bem.22369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 07/25/2021] [Accepted: 08/05/2021] [Indexed: 11/11/2022]
Abstract
Long-term potentiation (LTP) is considered the cellular basis of learning and memory. Extremely low-frequency electromagnetic fields (ELF-EMFs) are neuromodulation tools for regulating LTP. However, the temporal effects of short-term ELF-EMF stimulation on LTP are not yet known. In this study, we evaluated the time-dependent effects of 15 Hz/2 mT ELF-EMF stimulation on LTP at the Schaffer collateral-CA1 (SC-CA1) synapses in Sprague-Dawley rats. Hippocampal slices were exposed to three different modes of ELF-EMFs (sinusoidal, single-frequency pulse, and rhythm pulse) and durations (10, 20, 40, and 60 s). The baseline was recorded for 20 min and field excitatory postsynaptic potential (fEPSP) was recorded for 60 min using multi-electrode arrays (MEA) after plasticity induction using 100 Hz electrical high-frequency stimulation (HFS). Compared to the control group, the LTP decreased under three different magnetic fields and was proportional to time; that is, the longer the time, the greater the inhibition. We also compared the three magnetic fields and showed that the continuous sinusoidal magnetic field had the largest inhibitory rate of LTP, while pulsed and rhythm pulsed magnetic fields were similar. We showed that different modes of ELF-EMF stimulation had a time-dependent effect on LTP at Schaffer collateral-CA1 synapses, which provides experimental evidence for the treatment of related neurological diseases. © 2021 Bioelectromagnetics Society.
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Affiliation(s)
- Yu Zheng
- School of Life Sciences, Tiangong University, Tianjin, China
| | - Ling Zhao
- School of Life Sciences, Tiangong University, Tianjin, China
| | - Lei Dong
- State Key Laboratory of Precision Measurement Technology and Instruments, Tianjin University, Tianjin, China
| | - Chunxiao Tian
- School of Life Sciences, Tiangong University, Tianjin, China
| | - Pei Xia
- School of Life Sciences, Tiangong University, Tianjin, China
| | - Zijia Jin
- School of Life Sciences, Tiangong University, Tianjin, China
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Sakhnini L, Al-Ghareeb S, Khalil S, Ahmed R, Ameer AA, Kamal A. Effects of exposure to 50 Hz electromagnetic fields on Morris water-maze performance of prenatal and neonatal mice. ACTA ACUST UNITED AC 2018. [DOI: 10.1016/j.jaubas.2013.05.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Lama Sakhnini
- Department of Physics, College of Science, University of Bahrain, Shirpur Dist., P.O. Box 32038, Bahrain
| | - Sara Al-Ghareeb
- Physiology Department, College of Medicine, Arabian Gulf University, Manama, Bahrain
| | - Sahar Khalil
- Physiology Department, College of Medicine, Arabian Gulf University, Manama, Bahrain
| | - Reem Ahmed
- Physiology Department, College of Medicine, Arabian Gulf University, Manama, Bahrain
| | - Alaa Abdul Ameer
- Physiology Department, College of Medicine, Arabian Gulf University, Manama, Bahrain
| | - Amer Kamal
- Physiology Department, College of Medicine, Arabian Gulf University, Manama, Bahrain
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Akbarnejad Z, Esmaeilpour K, Shabani M, Asadi-Shekaari M, Saeedi Goraghani M, Ahmadi-Zeidabadi M. Spatial memory recovery in Alzheimer's rat model by electromagnetic field exposure. Int J Neurosci 2017; 128:691-696. [PMID: 29185809 DOI: 10.1080/00207454.2017.1411353] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
INTRODUCTION Although studies have shown a potential association between extremely low frequency electromagnetic fields (ELF-EMFs) exposure and Alzheimer's disease (AD), few studies have been conducted to investigate the effects of weak magnetic fields on brain functions such as cognitive functions in animal models. Therefore, this study aimed to investigate the effect of ELF-EMF exposure (50 Hz, 10 mT) on spatial learning and memory changes in AD rats. METHODS Amyloid-β (Aβ) 1-42 was injected into lateral ventricle to establish an AD rat model. The rats were divided into six groups: Group I (control); Group II (surgical sham); Group III (AD) Alzheimer's rat model; Group IV (MF) rats exposed to ELF-MF for 14 consecutive days; Group V (Aβ injection+M) rats exposed to magnetic field for 14 consecutive days from day 0 to 14 days after the Aβ peptide injection; Group VI (AD+M) rats exposed to magnetic field for 14 consecutive days after 2 weeks of Aβ peptide injection from 14th to 28th day . Morris water maze investigations were performed. RESULTS AD rats showed a significant impairment in learning and memory compared to control rats. The results showed that ELF-MF improved the learning and memory impairments in Aβ injection+M and AD+M groups. CONCLUSION Our results showed that application of ELF-MF not only has improving effect on different cognitive disorder signs of AD animals, but also disrupts the processes of AD rat model formation.
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Affiliation(s)
- Zeinab Akbarnejad
- a Neuroscience Research Center , Institute of Neuropharmacology, Kerman University of Medical Sciences , Kerman , Iran.,b ENT and Head & Neck Research Center , Iran University of Medical Sciences (IUMS) , Tehran , Iran
| | - Khadijeh Esmaeilpour
- a Neuroscience Research Center , Institute of Neuropharmacology, Kerman University of Medical Sciences , Kerman , Iran
| | - Mohammad Shabani
- a Neuroscience Research Center , Institute of Neuropharmacology, Kerman University of Medical Sciences , Kerman , Iran
| | - Majid Asadi-Shekaari
- a Neuroscience Research Center , Institute of Neuropharmacology, Kerman University of Medical Sciences , Kerman , Iran
| | - Monavvar Saeedi Goraghani
- a Neuroscience Research Center , Institute of Neuropharmacology, Kerman University of Medical Sciences , Kerman , Iran
| | - Meysam Ahmadi-Zeidabadi
- a Neuroscience Research Center , Institute of Neuropharmacology, Kerman University of Medical Sciences , Kerman , Iran
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Kumari K, Koivisto H, Viluksela M, Paldanius KMA, Marttinen M, Hiltunen M, Naarala J, Tanila H, Juutilainen J. Behavioral testing of mice exposed to intermediate frequency magnetic fields indicates mild memory impairment. PLoS One 2017; 12:e0188880. [PMID: 29206232 PMCID: PMC5714647 DOI: 10.1371/journal.pone.0188880] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 11/14/2017] [Indexed: 12/27/2022] Open
Abstract
Human exposure to intermediate frequency magnetic fields (MF) is increasing due to applications like electronic article surveillance systems and induction heating cooking hobs. However, limited data is available on their possible health effects. The present study assessed behavioral and histopathological consequences of exposing mice to 7.5 kHz MF at 12 or 120 μT for 5 weeks. No effects were observed on body weight, spontaneous activity, motor coordination, level of anxiety or aggression. In the Morris swim task, mice in the 120 μT group showed less steep learning curve than the other groups, but did not differ from controls in their search bias in the probe test. The passive avoidance task indicated a clear impairment of memory over 48 h in the 120 μT group. No effects on astroglial activation or neurogenesis were observed in the hippocampus. The mRNA expression of brain-derived neurotrophic factor did not change but expression of the proinflammatory cytokine tumor necrosis factor alpha mRNA was significantly increased in the 120 μT group. These findings suggest that 7.5 kHz MF exposure may lead to mild learning and memory impairment, possibly through an inflammatory reaction in the hippocampus.
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Affiliation(s)
- Kajal Kumari
- Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
- * E-mail:
| | | | - Matti Viluksela
- Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
- National Institute for Health and Welfare, Environmental Health Unit, Kuopio, Finland
| | | | - Mikael Marttinen
- Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Mikko Hiltunen
- Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Jonne Naarala
- Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
| | - Heikki Tanila
- A. I. Virtanen Institute, University of Eastern Finland, Kuopio, Finland
| | - Jukka Juutilainen
- Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
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10
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Zhang Y, Zhang Y, Yu H, Yang Y, Li W, Qian Z. Theta-gamma coupling in hippocampus during working memory deficits induced by low frequency electromagnetic field exposure. Physiol Behav 2017; 179:135-142. [DOI: 10.1016/j.physbeh.2017.05.033] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Revised: 03/29/2017] [Accepted: 05/31/2017] [Indexed: 11/28/2022]
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11
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Rostami A, Shahani M, Zarrindast MR, Semnanian S, Rahmati Roudsari M, Rezaei Tavirani M, Hasanzadeh H. Effects of 3 Hz and 60 Hz Extremely Low Frequency Electromagnetic Fields on Anxiety-Like Behaviors, Memory Retention of Passive Avoidance and Electrophysiological Properties of Male Rats. J Lasers Med Sci 2016; 7:120-5. [PMID: 27330708 DOI: 10.15171/jlms.2016.20] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
INTRODUCTION The effects of electromagnetic fields on biological organisms have been a controversial and also interesting debate over the past few decades, despite the wide range of investigations, many aspects of extremely low frequency electromagnetic fields (ELF/EMFs) effects including mechanism of their interaction with live organisms and also their possible biological applications still remain ambiguous. In the present study, we investigated whether the exposures of ELF/EMF with frequencies of 3 Hz and 60 Hz can affect the memory, anxiety like behaviors, electrophysiological properties and brain's proteome in rats. METHODS Male rats were exposed to 3 Hz and 60 Hz ELF/EMFs in a protocol consisting of 2 cycles of 2 h/day exposure for 4 days separated with a 2-day interval. Short term memory and anxiety like behaviors were assessed immediately, 1 and 2 weeks after the exposures. Effects of short term exposure were also assessed using electrophysiological approach immediately after 2 hours exposure. RESULTS Behavioral test revealed that immediately after the end of exposures, locomotor activity of both 3 Hz and 60 Hz exposed groups significantly decreased compared to sham group. This exposure protocol had no effect on anxiety like behavior during the 2 weeks after the treatment and also on short term memory. A significant reduction in firing rate of locus coeruleus (LC) was found after 2 hours of both 3 Hz and 60 Hz exposures. Proteome analysis also revealed global changes in whole brain proteome after treatment. CONCLUSION Here, some evidence regarding the fact that such exposures can alter locomotor activity and neurons firing rate in male rats were presented.
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Affiliation(s)
- Amin Rostami
- Faculty of Paramedical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Minoo Shahani
- Proteomics Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | - Saeed Semnanian
- Department of Physiology, School of Medical Sciences, Tarbiat Modarres University, Tehran, Iran
| | | | | | - Hadi Hasanzadeh
- Cancer Research Center and Department of Medical Physics, Semnan University of Medical Sciences, Semnan, Iran
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Navarro EA, Gomez-Perretta C, Montes F. Low intensity magnetic field influences short-term memory: A study in a group of healthy students. Bioelectromagnetics 2015; 37:37-48. [PMID: 26661640 DOI: 10.1002/bem.21944] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 10/23/2015] [Indexed: 11/11/2022]
Abstract
This study analyzes if an external magnetic stimulus (2 kHz and approximately 0.1 μT applied near frontal cortex) influences working memory, perception, binary decision, motor execution, and sustained attention in humans. A magnetic stimulus and a sham stimulus were applied to both sides of the head (frontal cortex close to temporal-parietal area) in young and healthy male test subjects (n = 65) while performing Sternberg's memory scanning task. There was a significant change in reaction time. Times recorded for perception, sustained attention, and motor execution were lower in exposed subjects (P < 0.01). However, time employed in binary decision increased for subjects exposed to magnetic fields. From results, it seems that a low intensity 2 kHz exposure modifies short-term working memory, as well as perception, binary decision, motor execution, and sustained attention.
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Affiliation(s)
- Enrique A Navarro
- Department of Applied Physics and Electromagnetism, Universitat de València, Valencia, Burjassot, Spain
| | | | - Francisco Montes
- Department of Statistics and Operation Research, Universitat de València, Valencia, Burjassot, Spain
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Li C, Xie M, Luo F, He C, Wang J, Tan G, Hu Z. The extremely low-frequency magnetic field exposure differently affects the AMPAR and NMDAR subunit expressions in the hippocampus, entorhinal cortex and prefrontal cortex without effects on the rat spatial learning and memory. ENVIRONMENTAL RESEARCH 2014; 134:74-80. [PMID: 25046815 DOI: 10.1016/j.envres.2014.06.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 06/18/2014] [Accepted: 06/28/2014] [Indexed: 06/03/2023]
Abstract
In the present study, we investigated the effects of chronic exposure (14 and 28 days) to a 50 Hz, 0.5 mT extremely low-frequency magnetic field (ELF-MF) on the NMDAR and AMPAR subunit expressions and rat spatial learning and memory. Using the Western blotting method, we found ELF-MF exposure specifically decreased the expressions of GluA2 in the EC post 28 day exposure and GluA3 of AMPAR subunits in the PFC after 14 day exposure, while it did not affect the AMPAR subunit expression in the hippocampus at both time points. As for NMDAR subunits, 14 day ELF-MF exposure significantly increased the levels of GluN2A and GluN2B in the hippocampus. Moreover, the levels of GluN1 and GluN2A were enhanced in the EC and PFC after two weeks of ELF-MF exposure. Interestingly, 28 day ELF-MF exposure induced a different expression pattern for NMDAR subunits. The increased GluN2A expression observed at 14 day post ELF-MF exposure was recovered after prolonged exposure in the hippocampus and PFC. In the EC, the increased expression of GluN1 achieved to control level and, specifically, a decrease in GluN2A level was observed. Surprisingly, neither 14 nor 28 day ELF-MF did affect the rat spatial reference memory as assessed by water maze. These results indicate that the dynamic and brain-region specific changes in ionotropic glutamate receptor expression induced by ELF-MF are insufficient to influence the rat spatial learning ability.
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Affiliation(s)
- Chao Li
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China
| | - Meilan Xie
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China
| | - Fenlan Luo
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China
| | - Chao He
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China
| | - Jiali Wang
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China
| | - Gang Tan
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China
| | - Zhian Hu
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China.
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Klose M, Grote K, Spathmann O, Streckert J, Clemens M, Hansen VW, Lerchl A. Effects of early-onset radiofrequency electromagnetic field exposure (GSM 900 MHz) on behavior and memory in rats. Radiat Res 2014; 182:435-47. [PMID: 25251701 DOI: 10.1667/rr13695.1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Female Wistar rats, from an age of 14 days to 19 months, were exposed in the head region for 2 h per day, 5 days per week, to a GSM-modulated 900 MHz radiofrequency electromagnetic field (RF-EMF). The average specific absorption rates (SAR) in the brain were 0 (sham), 0.7, 2.5 and 10 W/kg. To ensure a primary exposure of the head region, rats were fixed in restraining tubes of different sizes according to their increasing body weight. During the experiment, a set of 4 behavioral and learning tests (rotarod, Morris water maze, 8-arm radial maze, open field) were performed 3 times in juvenile, adult and presenile rats. In these tests, no profound differences could be identified between the groups. Only presenile rats of the cage control group showed a lower activity in two of these tests compared to the other groups presumably due to the lack of daily handling. The rotarod data revealed on some testing days significantly longer holding times for the sham-exposed rat vs. the exposed rat, but these findings were not consistent. During the first year, body weights of sham-exposed and exposed rats were not different from those of the cage controls, and thereafter only marginally lower, so that the effect of stress as confounder was probably negligible. The results of this study do not indicate harmful effects of long-term RF-EMF exposure even when begun at an early age on subsequent development, learning skills and behavior in rats, even at relatively high SAR values.
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Affiliation(s)
- Melanie Klose
- a School of Engineering and Science, Jacobs University Bremen, Bremen, Germany
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Autism-relevant social abnormalities in mice exposed perinatally to extremely low frequency electromagnetic fields. Int J Dev Neurosci 2014; 37:58-64. [PMID: 24970316 DOI: 10.1016/j.ijdevneu.2014.06.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 06/16/2014] [Accepted: 06/16/2014] [Indexed: 11/23/2022] Open
Abstract
The incidence of autism spectrum disorders (ASD) has been rising, but the causes of ASD remain largely unidentified. Collective data have implicated the increased human exposure to electromagnetic fields (EMF) in the increasing incidence of ASD. There are established biological effects of extremely low-frequency (ELF) EMF, but the relation to ASD is not investigated enough. In this study we examined the effects of perinatal exposure to ELF EMF on some ASD-relevant behavioral parameters in mice. The EMF was delivered via a Helmholtz coil pair. Male BALB/C mice were used and divided into exposed and control groups (n=8 and n=9, respectively). Tests were used to assess sociability, preference for social novelty, locomotion, anxiety, exploratory behavior, motor coordination, and olfaction. The examined mice were all males and exposed to EMF during the last week of gestation and for 7 days after delivery. The exposed mice demonstrated a lack of normal sociability and preference for social novelty while maintaining normal anxiety-like behavior, locomotion, motor coordination, and olfaction. Exposed mice also demonstrated decreased exploratory activity. We concluded that these results are supportive of the hypothesis of a causal link between exposure to ELF-EMF and ASD; however, replications of the study with further tests are recommended.
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16
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LI Y, ZHANG C, SONG T. Disturbance of the Magnetic Field Did Not Affect Spatial Memory. Physiol Res 2014; 63:377-85. [DOI: 10.33549/physiolres.932594] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Extremely low-frequency magnetic field (ELF-MF) has been suggested to influence the cognitive capability but this should be dynamically evaluated in a longitudinal study. Previous training can affect performance, but the influence under magnetic field is unclear. This study aims to evaluate the effects of previous training and ELF-MF exposure on learning and memory using the Morris water maze (MWM). Sprague-Dawley rats were subjected to MWM training, ELF-MF exposure (50 Hz, 100 µT), or ELF-MF exposure combined with MWM training for 90 days. Normal rats were used as controls. The MWM was used to test. The data show that the rats exposed to training and ELF-MF with training performed better on spatial acquisition when re-tested. However, during the probe trial the rats showed no change between the training phase and the test phase. Compared with the control group, the ELF-MF group showed no significant differences. These results confirm that previous training can improve the learning and memory capabilities regarding spatial acquisition in the MWM and this effect can last for at least 90 days. However, this improvement in learning and memory capabilities was not observed during the probe trial. Furthermore, ELF-MF exposure did not interfere with the improvement in learning and memory capabilities.
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Affiliation(s)
| | | | - T. SONG
- Beijing Key Laboratory of Bioelectromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China
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17
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Salunke BP, Umathe SN, Chavan JG. Experimental evidence for involvement of nitric oxide in low frequency magnetic field induced obsessive compulsive disorder-like behavior. Pharmacol Biochem Behav 2014; 122:273-8. [PMID: 24780504 DOI: 10.1016/j.pbb.2014.04.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 03/27/2014] [Accepted: 04/18/2014] [Indexed: 01/12/2023]
Abstract
It is well documented that extremely low frequency magnetic field (ELF MF) produced effects on the function of nervous system in humans and laboratory animals. Dopaminergic and serotonergic pathways have been implicated in obsessive compulsive disorder (OCD). Recently involvement of nitric oxide (NO) in OCD-like behavior is suggested. Hence, the present study was carried out to understand the involvement of dopamine, serotonin and NO in ELF MF induced OCD-like behavior. Swiss albino mice were exposed to ELF MF (50 Hz, 10G) for 8 h/day for 7, 30, 60, 90 and 120 days by subjecting them to Helmholtz coils. OCD-like behavior was assessed in terms of marble burying behavior (MBB) test. Results revealed that ELF MF induced time dependant MBB, on 7th, 30th, 60th, 90th, and 120th exposure day. Further, levels of dopamine, serotonin and NO after 120 days of ELF MF exposure were determined in the regions of the brain. The neurohumoral studies revealed that exposure to ELF MF increased NO levels in cortex, hippocampus and hypothalamus, and levels of dopamine and serotonin remain unaffected. As OCD-like behavior after ELF MF exposure was associated with higher levels of NO with no significant change in serotonin and dopamine. The effect of such exposure was studied in groups concurrently treated with NO modulators, NO precursor, L-ARG (400 mg/kg) or NOS inhibitor, L-NAME (15.0mg/kg) or 7-NI (10.0 mg/kg). These treatments revealed that NO precursor exacerbated and NOS inhibitors attenuated ELF MF induced OCD-like behavior with corresponding changes in the levels of NO.
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Affiliation(s)
- Balwant P Salunke
- Department of Pharmaceutical Sciences, Rashtrasant Tukadoji Maharaj Nagpur University, Mahatma Jyotiba Fuley Shaikshanik Parisar, Amravati Road, Nagpur, MS,440 033, India.
| | - Sudhir N Umathe
- Department of Pharmaceutical Sciences, Rashtrasant Tukadoji Maharaj Nagpur University, Mahatma Jyotiba Fuley Shaikshanik Parisar, Amravati Road, Nagpur, MS,440 033, India
| | - Jagatpalsingh G Chavan
- Department of Pharmaceutical Sciences, Rashtrasant Tukadoji Maharaj Nagpur University, Mahatma Jyotiba Fuley Shaikshanik Parisar, Amravati Road, Nagpur, MS,440 033, India
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18
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Wang X, Zhao K, Wang D, Adams W, Fu Y, Sun H, Liu X, Yu H, Ma Y. Effects of exposure to a 50 Hz sinusoidal magnetic field during the early adolescent period on spatial memory in mice. Bioelectromagnetics 2013; 34:275-84. [DOI: 10.1002/bem.21775] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2011] [Accepted: 11/29/2012] [Indexed: 11/08/2022]
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19
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Kitaoka K, Kitamura M, Aoi S, Shimizu N, Yoshizaki K. Chronic exposure to an extremely low-frequency magnetic field induces depression-like behavior and corticosterone secretion without enhancement of the hypothalamic-pituitary-adrenal axis in mice. Bioelectromagnetics 2012; 34:43-51. [DOI: 10.1002/bem.21743] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Accepted: 06/01/2012] [Indexed: 12/30/2022]
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20
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Park WH, Chae YJ, Soh KS, Lee BC, Pyo MY. Inhibition of pentylenetetrazole-induced seizure in mice by using a 4 Hz magnetic field: a comparative study with a 60 Hz magnetic field. Electromagn Biol Med 2012; 31:293-8. [DOI: 10.3109/15368378.2012.662191] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Won-Hee Park
- Pharmaceutical Analysis Team, Seoul Metropolitan Government Research Institute of Public Health & Environment, Seoul, Korea
| | - Young-Joo Chae
- Pharmaceutical Analysis Team, Seoul Metropolitan Government Research Institute of Public Health & Environment, Seoul, Korea
| | - Kwang-Sup Soh
- Nano Primo Research Center, Advanced Institute of Convergence Technology, Seoul National University,
Suwon, Korea
| | - Byung-Cheon Lee
- Ki Primo Research Laboratory, KI for Information Technology Convergence, Division of Electrical Engineering, Korea Advanced Institute of Science and Technology,
Daejeon, Korea
- Pharmacopuncture Medical Research Institute, Korean Pharmacopuncture Institute,
Seoul, Korea
| | - Myoung-Yun Pyo
- Laboratory of Hygienic Pharmacy, College of Pharmacy, Sookmyung Women's University,
Seoul, Korea
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21
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Foroozandeh E, Derakhshan-Barjoei P, Jadidi M. Toxic effects of 50 Hz electromagnetic field on memory consolidation in male and female mice. Toxicol Ind Health 2012; 29:293-9. [DOI: 10.1177/0748233711433931] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In this study, the effect of exposure to an 8 mT, 50 Hz extremely low-frequency electromagnetic field (ELF EMF) on memory consolidation of adult male and female mice was studied. For this purpose male and female mice were randomly distributed among six groups ( n = 10 in each group). Using passive avoidance task, despite its natural tendency, mouse learns to stay on a small platform to avoidant electric shock. Immediately after the learning session, laboratory animals in the experimental groups were placed in an 8 mT, 50 Hz sinusoidal EMF for 4 h. The second male and female groups were sham exposed (exposure device off) and the third groups were considered as the controls. Twenty-four hours after the learning session, the animals were placed on small platform again and step-down latency was measured as the memory consolidation index. Significant ( p < 0.05) decreases were determined among groups in memory function and results showed that exposure to an 8 mT, 50 Hz EMF for 4 h has devastating effects on memory consolidation in male and female mice.
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Affiliation(s)
- Elham Foroozandeh
- Department of Psychology, Young Researchers Club, Naein Branch, Islamic Azad University, Iran
| | - Pouya Derakhshan-Barjoei
- Department of Electrical Engineering, Young Researchers Club, Naein Branch, Islamic Azad University, Iran
| | - Mohsen Jadidi
- Department of Psychology, Young Researchers Club, Bandargaz Branch, Islamic Azad University, Iran
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22
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Elferchichi M, Ammari M, Maaroufi K, Sakly M, Abdelmelek H. Effects of exposure to static magnetic field on motor skills and iron levels in plasma and brain of rats. Brain Inj 2011; 25:901-8. [DOI: 10.3109/02699052.2011.581640] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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23
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Sun H, Che Y, Liu X, Zhou D, Miao Y, Ma Y. Effects of prenatal exposure to a 50-Hz magnetic field on one-trial passive avoidance learning in 1-day-old chicks. Bioelectromagnetics 2010; 31:150-5. [PMID: 19739132 DOI: 10.1002/bem.20540] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We investigated memory impairment in newly hatched chicks following in ovo exposure to a 50-Hz magnetic field (MF) of 2 mT (60 min/day) on embryonic days 12-18. Isolated and paired chicks were used to test the effect of stress during training, and memory retention was tested at 10, 30, and 120 min, following exposure to a bitter-tasting bead (100% methylanthranilate). Results showed that memory was intact at 10 min in both isolated and paired chicks with or without MF exposure. However, while isolated chicks had good memory retention levels at 30 and 120 min, those exposed to MF did not. The results suggest a potential disruption of memory formation following in ovo exposure to MF, with this effect only evident in the more stressed, isolated chicks.
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Affiliation(s)
- Huaying Sun
- Laboratory of Primate Neuroscience Research, Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, #32 Jiao Chang Dong Lu, Kunming, Yunnan, PR China
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24
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Ammari M, Jeljeli M, Maaroufi K, Sakly M, Abdelmelek H, Roy V. Static Magnetic Field Exposure Affects Behavior and Learning in Rats. Electromagn Biol Med 2009; 27:185-96. [DOI: 10.1080/15368370802072158] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Mohamed Ammari
- Faculté des Sciences de Bizerte, Laboratoire de Physiologie Intégrée, Jarzouna, Tunisia
| | - Mustpha Jeljeli
- Faculté des Sciences de Bizerte, Laboratoire de Physiologie Intégrée, Jarzouna, Tunisia
- Université Tunis El Manar, Institut Supérieur des Sciences Humaines de Tunis, Tunis, Tunisia
| | - Karima Maaroufi
- Faculté des Sciences de Bizerte, Laboratoire de Physiologie Intégrée, Jarzouna, Tunisia
| | - Mohsen Sakly
- Faculté des Sciences de Bizerte, Laboratoire de Physiologie Intégrée, Jarzouna, Tunisia
| | - Hafedh Abdelmelek
- Faculté des Sciences de Bizerte, Laboratoire de Physiologie Intégrée, Jarzouna, Tunisia
| | - Vincent Roy
- Laboratoire de Neurobiologie de l'Apprentissage, Faculté des Sciences, Université des Rouen, UPRES PSY.CO – EA1780, IFRMP23, 76821, Mont-Saint-Aignan, Cedex, France
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25
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Ahuja YR, Bhargava SC, Ratnakar KS. Electric and Magnetic Fields in Stem Cell Research. Electromagn Biol Med 2009. [DOI: 10.1080/15368370500205480] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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26
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Varró P, Szemerszky R, Bárdos G, Világi I. Changes in synaptic efficacy and seizure susceptibility in rat brain slices following extremely low-frequency electromagnetic field exposure. Bioelectromagnetics 2009; 30:631-40. [DOI: 10.1002/bem.20517] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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27
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Maaroufi K, Had-Aissouni L, Melon C, Sakly M, Abdelmelek H, Poucet B, Save E. Effects of prolonged iron overload and low frequency electromagnetic exposure on spatial learning and memory in the young rat. Neurobiol Learn Mem 2009; 92:345-55. [PMID: 19394433 DOI: 10.1016/j.nlm.2009.04.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Revised: 04/09/2009] [Accepted: 04/16/2009] [Indexed: 11/30/2022]
Abstract
Low-frequency electromagnetic fields (EMF) have been suggested to affect the brain via alterations of blood-brain barrier permeability to iron. Because of an immature blood-brain barrier, the young brain may be particularly vulnerable to EMF exposure. It is therefore possible that behavioral and neurotoxic effects resulting from EMF-induced iron excess in the brain would be greater in young adults. The objective of the present study was to investigate the interaction between low-frequency EMF and iron overload in young rats. In Experiment 1, we tested the effects of iron overload on spatial learning and memory. Iron treatment did not affect performance in a reference (Morris water maze) and a working memory task (8-arm radial maze). In contrast, detection of a spatial change in an object exploration task was impaired. These effects correlated with modifications of the serotoninergic metabolism. In Experiment 2, the combination of EMF exposure and iron overload was tested. As in Experiment 1, rats were not impaired in reference and working memory tasks but were mildly impaired in the detection of the spatial change. Overall, the results showed an effect of iron overload on spontaneous spatial memory processes. However, low-frequency EMF exposure did not potentiate the effects of iron overload in young rats.
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Affiliation(s)
- Karima Maaroufi
- Laboratory of Neurobiology and Cognition, UMR 6155 Aix-Marseille Université CNRS, Marseille, France
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28
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Capone F, Dileone M, Profice P, Pilato F, Musumeci G, Minicuci G, Ranieri F, Cadossi R, Setti S, Tonali PA, Di Lazzaro V. Does exposure to extremely low frequency magnetic fields produce functional changes in human brain? J Neural Transm (Vienna) 2009; 116:257-65. [PMID: 19189041 DOI: 10.1007/s00702-009-0184-2] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Accepted: 01/09/2009] [Indexed: 12/13/2022]
Abstract
Behavioral and neurophysiological changes have been reported after exposure to extremely low frequency magnetic fields (ELF-MF) both in animals and in humans. The physiological bases of these effects are still poorly understood. In vitro studies analyzed the effect of ELF-MF applied in pulsed mode (PEMFs) on neuronal cultures showing an increase in excitatory neurotransmission. Using transcranial brain stimulation, we studied noninvasively the effect of PEMFs on several measures of cortical excitability in 22 healthy volunteers, in 14 of the subjects we also evaluated the effects of sham field exposure. After 45 min of PEMF exposure, intracortical facilitation produced by paired pulse brain stimulation was significantly enhanced with an increase of about 20%, while other parameters of cortical excitability remained unchanged. Sham field exposure produced no effects. The increase in paired-pulse facilitation, a physiological parameter related to cortical glutamatergic activity, suggests that PEMFs exposure may produce an enhancement in cortical excitatory neurotransmission. This study suggests that PEMFs may produce functional changes in human brain.
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Affiliation(s)
- F Capone
- Institute of Neurology, Università Cattolica, L.go A. Gemelli 8, 00168, Rome, Italy
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29
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Wiholm C, Lowden A, Kuster N, Hillert L, Arnetz BB, Akerstedt T, Moffat SD. Mobile phone exposure and spatial memory. Bioelectromagnetics 2009; 30:59-65. [PMID: 18792947 DOI: 10.1002/bem.20443] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Radiofrequency (RF) emission during mobile phone use has been suggested to impair cognitive functions, that is, working memory. This study investigated the effects of a 2 1/2 h RF exposure (884 MHz) on spatial memory and learning, using a double-blind repeated measures design. The exposure was designed to mimic that experienced during a real-life mobile phone conversation. The design maximized the exposure to the left hemisphere. The average exposure was peak spatial specific absorption rate (psSAR10g) of 1.4 W/kg. The primary outcome measure was a "virtual" spatial navigation task modeled after the commonly used and validated Morris Water Maze. The distance traveled on each trial and the amount of improvement across trials (i.e., learning) were used as dependent variables. The participants were daily mobile phone users, with and without symptoms attributed to regular mobile phone use. Results revealed a main effect of RF exposure and a significant RF exposure by group effect on distance traveled during the trials. The symptomatic group improved their performance during RF exposure while there was no such effect in the non-symptomatic group. Until this new finding is further investigated, we can only speculate about the cause.
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Affiliation(s)
- Clairy Wiholm
- Department of Family Medicine and Public Health Sciences, Division of Occupational and Environmental Health, Wayne State University, Detroit, Michigan 48201, USA.
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30
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Del Seppia C, Mezzasalma L, Messerotti M, Cordelli A, Ghione S. Investigations of a simulated geomagnetic field experienced by the International Space Station on attentional performance. Bioelectromagnetics 2009; 30:45-51. [PMID: 18720370 DOI: 10.1002/bem.20438] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We have previously reported that the exposure to an abnormal magnetic field simulating the one encountered by the International Space Station (ISS) orbiting around the Earth may enhance autonomic response to emotional stimuli. Here we report the results of the second part of that study which tested whether this field also affects cognitive functions. Twenty-four volunteers participated in the study, 12 exposed to the natural geomagnetic field and 12 to the magnetic field encountered by ISS. The test protocol consisted of a set of eight tests chosen from a computerized test battery for the assessment of attentional performance. The duration of exposure was 90 min. No effect of exposure to ISS magnetic field was observed on attentional performance.
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Affiliation(s)
- Cristina Del Seppia
- Institute of Clinical Physiology, National Council of Research (CNR), Pisa, Italy.
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31
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Fu Y, Wang C, Wang J, Lei Y, Ma Y. LONG-TERM EXPOSURE TO EXTREMELY LOW-FREQUENCY MAGNETIC FIELDS IMPAIRS SPATIAL RECOGNITION MEMORY IN MICE. Clin Exp Pharmacol Physiol 2008; 35:797-800. [DOI: 10.1111/j.1440-1681.2008.04922.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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32
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Chronic exposure to low-intensity magnetic field improves acquisition and maintenance of memory. Neuroreport 2008; 19:549-52. [DOI: 10.1097/wnr.0b013e3282f8b1a0] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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33
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Che Y, Sun H, Cui Y, Zhou D, Ma Y. Effects of exposure to 50Hz magnetic field of 1mT on the performance of detour learning task by chicks. Brain Res Bull 2007; 74:178-82. [PMID: 17683805 DOI: 10.1016/j.brainresbull.2007.06.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2007] [Revised: 05/24/2007] [Accepted: 06/12/2007] [Indexed: 11/15/2022]
Abstract
In the present study, we examined the effects of exposure to an extremely low-frequency magnetic field of 1 mT intensity on learning and memory in Lohmann brown domestic chicks using detour learning task. These results show that 20 h/day exposure to a low-frequency magnetic field induces a significant impairment in detour learning but 50 min/day exposure has no effect.
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Affiliation(s)
- Yi Che
- Kunming Institute of Zoology, Chinese Academy of Science, Kunming 650223, PR China.
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34
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Study of high-frequency electromagnetic field effect on some somatic and neuro-behavioral characteristics in healthy and neurodefective mice. ACTA ACUST UNITED AC 2007. [DOI: 10.1007/s10669-007-9071-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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35
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Park YJ, Park WJ, Yim SH, Yang SJ, Sun YL, Jeong JH, Park ES. Extremely Low Frequency Magnetic Field is an Environmental Stress Factor by Exerting Oxidative Stress. Biomol Ther (Seoul) 2007. [DOI: 10.4062/biomolther.2007.15.1.058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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36
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Ferreira AR, Bonatto F, de Bittencourt Pasquali MA, Polydoro M, Dal-Pizzol F, Fernández C, de Salles AAA, Moreira JCF. Oxidative stress effects on the central nervous system of rats after acute exposure to ultra high frequency electromagnetic fields. Bioelectromagnetics 2006; 27:487-93. [PMID: 16715528 DOI: 10.1002/bem.20233] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Mobile telephones and their base stations are an important source of ultra high frequency electromagnetic fields (UHF-EMFs; 800-1800 MHz) and their utilization is increasing all over the world. Epidemiological studies have suggested that low energy UHF-EMFs may have biological effects, such as changes in oxidative metabolism after exposure. Therefore, we have investigated the effect of acute UHF-EMF exposure on non-enzymatic antioxidant defense and lipid and protein oxidative damage in the rat frontal cortex and hippocampus. We have used malondialdehyde (MDA) and carbonyl assays to assess lipid and protein oxidative damages, respectively. No changes in lipid and protein damage, and also in non-enzymatic defense were found in frontal cortex or hippocampus. These results suggest that acute UHF-EMF exposure is not able to produce detectable oxidative stress in rats from any age tested. However, more tests using a longer period of exposure and evaluating other tissues are necessary to ensure that there is no health risk associated with the use of mobile phones.
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Affiliation(s)
- Amâncio R Ferreira
- Departamento de Bioquímica, Centro de Estudos em Estresse Oxidativo, ICBS, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
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37
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Del Seppia C, Mezzasalma L, Messerotti M, Cordelli A, Ghione S. Simulation of the geomagnetic field experienced by the International Space Station in its revolution around the Earth: effects on psychophysiological responses to affective picture viewing. Neurosci Lett 2006; 400:197-202. [PMID: 16529860 DOI: 10.1016/j.neulet.2006.02.045] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2005] [Revised: 02/10/2006] [Accepted: 02/17/2006] [Indexed: 11/28/2022]
Abstract
There is evidence suggesting that exposure to an abnormal magnetic environment may produce psychophysiological effects related to abnormalities in responses to stress. This may be of relevance for space medicine where astronauts are exposed to a magnetic field different from that exerted by the Earth. Aim of this study was to assess how the exposure of the head to a magnetic field simulating the one encountered by the International Space Station (ISS) during a single orbit (90 min) around the Earth affects the cardiovascular and psychophysiological parameters. Twenty-four human volunteers were studied double blindly in random order under sham and magnetic exposure. During exposure, the persons were shown a set of pictures of different emotional content while subjective self-rating, skin conductance (SC), blood pressure (BP), and heart rate (HR) were measured. In addition, BP, HR, and tooth pain threshold were assessed before and after exposure. While subjects were under magnetic exposure, skin conductance was strongly differentiated (F(2,36)=22.927; p=0.0001), being high during emotionally involving (positive and negative) pictures and low during neutral pictures. Conversely, when subjects were under sham exposure, no significant differences were observed. There was, however, a trend for higher heart rate during picture viewing under magnetic exposure as compared to sham exposure. No effects were found for the other variables. These results suggest that an abnormal magnetic field that simulates the one encountered by ISS orbiting around the Earth may enhance autonomic response to emotional stimuli.
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Affiliation(s)
- Cristina Del Seppia
- Institute of Clinical Physiology, National Council of Research (CNR), Via Moruzzi 1, 56124 Pisa, Italy.
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38
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Janać B, Pesić V, Jelenković A, Vorobyov V, Prolić Z. Different effects of chronic exposure to ELF magnetic field on spontaneous and amphetamine-induced locomotor and stereotypic activities in rats. Brain Res Bull 2005; 67:498-503. [PMID: 16216699 DOI: 10.1016/j.brainresbull.2005.07.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2004] [Revised: 06/29/2005] [Accepted: 07/28/2005] [Indexed: 01/07/2023]
Abstract
The effects of chronic (7 days) exposure to an extremely low frequency magnetic field (ELF-MF, 50 Hz, 0.5 mT) on spontaneous and amphetamine-induced (1.5mg/kg, i.p.) locomotor and stereotypic activities in adult rats were examined by open field test for 2h on exposure days 1, 3, and 7. After 1 day of exposure to ELF-MF, the spontaneous locomotor activity was increased clearly at the first hour of observation and significantly at the second one as compared to the corresponding values in other series with ELF-MF and sham-exposed animals. After 7 days of exposure to ELF-MF, an amphetamine enhancing effect on the locomotor activity was significantly reduced at the second hour of observation as compared to that in 1-day- and sham-exposed rats treated with amphetamine. In contrast to the locomotor activity, the amphetamine-induced stereotypic behaviour in 7-day pre-exposed rats was significantly reduced at the first hour versus sham-exposed rats. While at the second hour of observation this effect was significant as compared to 1- and 3-day exposed animals (but not sham-exposed rats). Our results indicate that an extremely low frequency magnetic field is able to affect differently two types of behaviour, which are dependent on both the time course of exposure and the imbalance in the brain mediatory systems.
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Affiliation(s)
- Branka Janać
- Laboratory of Electrophysiology and Behaviour, Department of Neurobiology and Immunology, Institute for Biological Research, Bulevar Despota Stefana 142, 11060 Belgrade, Serbia and Montenegro.
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39
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Ghaly M, Teplitz D. The biologic effects of grounding the human body during sleep as measured by cortisol levels and subjective reporting of sleep, pain, and stress. J Altern Complement Med 2005; 10:767-76. [PMID: 15650465 DOI: 10.1089/acm.2004.10.767] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
OBJECTIVES Diurnal cortisol secretion levels were measured and circadian cortisol profiles were evaluated in a pilot study conducted to test the hypothesis that grounding the human body to earth during sleep will result in quantifiable changes in cortisol. It was also hypothesized that grounding the human body would result in changes in sleep, pain, and stress (anxiety, depression, irritability), as measured by subjective reporting. SUBJECTS AND INTERVENTIONS Twelve (12) subjects with complaints of sleep dysfunction, pain, and stress were grounded to earth during sleep for 8 weeks in their own beds using a conductive mattress pad. Saliva tests were administered to establish pregrounding baseline cortisol levels. Levels were obtained at 4-hour intervals for a 24-hour period to determine the circadian cortisol profile. Cortisol testing was repeated at week 6. Subjective symptoms of sleep dysfunction, pain, and stress were reported daily throughout the 8-week test period. RESULTS Measurable improvements in diurnal cortisol profiles were observed, with cortisol levels significantly reduced during night-time sleep. Subjects' 24-hour circadian cortisol profiles showed a trend toward normalization. Subjectively reported symptoms, including sleep dysfunction, pain, and stress, were reduced or eliminated in nearly all subjects. CONCLUSIONS Results indicate that grounding the human body to earth ("earthing") during sleep reduces night-time levels of cortisol and resynchronizes cortisol hormone secretion more in alignment with the natural 24-hour circadian rhythm profile. Changes were most apparent in females. Furthermore, subjective reporting indicates that grounding the human body to earth during sleep improves sleep and reduces pain and stress.
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Sienkiewicz Z, Jones N, Bottomley A. Neurobehavioural effects of electromagnetic fields. Bioelectromagnetics 2005; Suppl 7:S116-26. [PMID: 16059919 DOI: 10.1002/bem.20141] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Very few laboratory studies in children have explored the effects of exposure to low level electromagnetic fields (EMFs) on neurobehavioural function. Studies investigating effect on neurotransmitters, cognitive function and brain activity in adults and animals indicate that acute exposure to EMFs does not appear to engender any consistent physiological or behavioural impairment although a few subtle effects may occur. This suggests that exposure of children to low level EMFs may not cause significant detrimental effects on brain function. However the available evidence is not sufficient to draw any definite conclusions, and further laboratory studies are required. In particular, experiments investigating the effects of radiofrequency (RF) fields on the performance of well-characterised cognitive and behavioural tasks by immature and developing animals are recommended, if studies with children cannot be performed for ethical and practical reasons.
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Affiliation(s)
- Zenon Sienkiewicz
- Health Protection Agency, Centre for Radiation, Chemical and Environmental Hazards, Radiation Protection Division, Chilton, Didcot, United Kingdom.
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Vázquez-García M, Elías-Viñas D, Reyes-Guerrero G, Domínguez-González A, Verdugo-Díaz L, Guevara-Guzmán R. Exposure to extremely low-frequency electromagnetic fields improves social recognition in male rats. Physiol Behav 2004; 82:685-90. [PMID: 15327917 DOI: 10.1016/j.physbeh.2004.06.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2003] [Revised: 04/30/2004] [Accepted: 06/02/2004] [Indexed: 10/26/2022]
Abstract
The effect of exposure to low-frequency electromagnetic fields (ELF EMFs) on social recognition was studied. The test was based upon a comparison between two encounters of an adult rat and a conspecific juvenile, separated by an interexposure interval (IEI). The exposure to ELF EMF of 1 mT intensity during 2 h for 9 days increased the duration of short-term memory of adult male Wistar rats up to 300 min. These data indicate, for the first time, that ELF EMF improves social recognition memory in rats.
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Affiliation(s)
- Mario Vázquez-García
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Apdo. Postal 70250, México, D.F., 04510, Mexico.
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Pesić V, Janać B, Jelenković A, Vorobyov V, Prolić Z. Non-linearity in combined effects of ELF magnetic field and amphetamine on motor activity in rats. Behav Brain Res 2004; 150:223-7. [PMID: 15033296 DOI: 10.1016/j.bbr.2003.07.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2003] [Revised: 07/09/2003] [Accepted: 07/25/2003] [Indexed: 11/20/2022]
Abstract
The effects of short-term (15 min) pre-exposure of rats to extremely low-frequency magnetic field (ELF-MF, 50 Hz, 6 mT) on their motor (locomotor and stereotypic) activity induced by d-amphetamine sulphate (AMPH) at different doses (0.5, 1.5 and 4.5mg/kg, i.p.) were studied in the open field test. In saline-treated rats both parameters of motor activity were unaffected by ELF-MF irradiation. The rats pre-exposed to ELF-MF and injected with the lowest dose of AMPH showed the same locomotor activity as control animals, while their stereotypic behaviour was significantly elevated. ELF-MF in combination with AMPH at higher doses significantly enhanced motor activity when compared with values obtained in both control and combined experiments with the lowest dose of the drug. However, only combined locomotor effect at the middle dose of AMPH was significantly greater than those observed in corresponding experiments with AMPH alone. These results demonstrate that acute short-term exposure to ELF-MF is able to modify a motor activity in dependence on the extent of AMPH-induced neurotransmitter imbalance.
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Affiliation(s)
- Vesna Pesić
- Laboratory of Electrophysiology and Behaviour, Department of Neurobiology and Immunology, Institute for Biological Research, 29 Novembra 142, 11060 Belgrade, Serbia and Montenegro, Yugoslavia
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Jiang ML, Han TZ, Pang W, Li L. Gender- and age-specific impairment of rat performance in the Morris water maze following prenatal exposure to an MRI magnetic field. Brain Res 2004; 995:140-4. [PMID: 14644479 DOI: 10.1016/j.brainres.2003.09.060] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We examined the effects of prenatal exposure (40 min/day, gestation days 12-18) of rats to a magnetic resonance imaging (MRI) magnetic field (MF) on their performance in the Morris water maze. At 2 months of age, female rats showed impaired performance. The animals spent longer time swimming and used inefficient strategies. However, no significant effects on maze performance were observed at 1 and 5 months of age. No evident maze performance deficit was detected in male rats prenatally exposed to the magnetic field. Thus, we conclude that prenatal exposure to MRI magnetic field induces cognitive/behavioral deficits in female rats at a specific age.
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Affiliation(s)
- Ma-Li Jiang
- Department of Physiology, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, PR China
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Dubreuil D, Jay T, Edeline JM. Head-only exposure to GSM 900-MHz electromagnetic fields does not alter rat’s memory in spatial and non-spatial tasks. Behav Brain Res 2003; 145:51-61. [PMID: 14529805 DOI: 10.1016/s0166-4328(03)00100-1] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Over the last decade, exposure to high frequency (2450 MHz) electromagnetic fields (EMFs) has been found to induce performance deficit in rodents in spatial memory tasks. As concern was expressed about potential biological effects of mobile communication microwaves, studies testing the effects of signals such as GSM were required. In a previous study, using head-only exposure to 900 MHz GSM EMF, we could not demonstrate any behavioural deficit in two simple learning tasks. The present study aimed at extending these results with more complex spatial learning tasks and a non-spatial task. In a first experiment, rats were trained in a radial-arm maze with a 10-s confinement between each visited arm. In a second experiment, a 15-min intra-trial delay was introduced after four visited arms. In a third experiment, non-spatial memory was tested in an object recognition task. In all experiments, performance of the head-only exposed rats (1 and 3.5 W/kg) was compared with that of sham and control rats. In the first experiment, a slightly improved performance was found after 3.5 W/kg exposure, a result that was not observed in the delay-task. In the third experiment, although some effects on exploratory activity were found, recognition memory was unaffected in exposed rats. Altogether, this set of experiments provides no evidence indicating that spatial and non-spatial memory can be affected by a 45-min head-only exposure to 900 MHz GSM EMF.
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Affiliation(s)
- Diane Dubreuil
- Laboratoire de Neurobiologie de l'Apprentissage, de la Mémoire et de la Communication, UMR CNRS 8620, Université Paris-Sud, 91405 Orsay Cedex, France
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Håkansson N, Gustavsson P, Johansen C, Floderus B. Neurodegenerative diseases in welders and other workers exposed to high levels of magnetic fields. Epidemiology 2003; 14:420-6; discussion 427-8. [PMID: 12843765 DOI: 10.1097/01.ede.0000078446.76859.c9] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Previous work has suggested an increase in risk of amyotrophic lateral sclerosis (ALS) and Alzheimer's disease among workers exposed to extremely low-frequency magnetic fields (ELF-MF). We evaluated the relation between ELF-MF from occupational exposures and mortality from neurodegenerative diseases. METHODS The study was based on a cohort of Swedish engineering industry workers, comprising 537,692 men and 180,529 women. The cohort was matched against the 3 most recent censuses and The Causes of Death Registry. Levels of ELF-MF exposure were obtained by linking occupation according to the censuses to a job exposure matrix. We used 4 levels of exposure and considered both the primary and contributing causes of death, 1985-96. RESULTS The risk of Alzheimer's disease as primary or contributing cause of death increased with increasing exposure to ELF-MF among both men and women, with a relative risk (RR) of 4.0 and a 95% confidence interval (95% CI) of 1.4-11.7 in the highest exposure group for both sexes combined. There was a RR of 2.2 (95% CI: 1.0-4.7) for ALS in the highest exposure group with the suggestion of an exposure-response relationship. No evidence of increased risk was seen for Parkinson's disease or multiple sclerosis. CONCLUSIONS The findings support previous observations of an increased risk of Alzheimer's disease and ALS among employees occupationally exposed to ELF-MF. Further studies based on morbidity data are warranted.
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Affiliation(s)
- Niclas Håkansson
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
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Abstract
Understanding the factors that allow biological systems to reliably self-assemble consistent, highly complex, four dimensional patterns on many scales is crucial for the biomedicine of cancer, regeneration, and birth defects. The role of chemical signaling factors in controlling embryonic morphogenesis has been a central focus in modern developmental biology. While the role of tensile forces is also beginning to be appreciated, another major aspect of physics remains largely neglected by molecular embryology: electromagnetic fields and radiations. The continued progress of molecular approaches to understanding biological form and function in the post genome era now requires the merging of genetics with functional understanding of biophysics and physiology in vivo. The literature contains much data hinting at an important role for bioelectromagnetic phenomena as a mediator of morphogenetic information in many contexts relevant to embryonic development. This review attempts to highlight briefly some of the most promising (and often underappreciated) findings that are of high relevance for understanding the biophysical factors mediating morphogenetic signals in biological systems. These data originate from contexts including embryonic development, neoplasm, and regeneration.
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Affiliation(s)
- Michael Levin
- Department of Cytokine Biology, The Forsyth Institute, Boston, Massachusetts 02114, USA.
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Abstract
Despite intensive investigation into the mechanisms underlying the memory process, the physical bases for this superior cognitive function remain elusive. Recall of past events and actions depends on the generation of complex memory carriers that would have to integrate many items of information. Some human memory processes, like contextual recall, work at such high speed and integrate such a large number of cortical neurons and neuronal networks that molecular mechanisms of information storage and synaptic transmission seem insufficient. This limitation argues against molecular information storage mechanisms as being truly effective carriers for the memory process. In this paper, I propose that any type of information can be stored in the form of 'neuronal activity-associated magnetic fields' that would record information in much the same way as the magnetic tape of a tape recorder. Integration and/or combination of the neuronal activity-associated magnetic fields throughout the complex three-dimensional structure of the human cortex could provide a storage medium for high-speed processing and discrimination that would support the complexity of the human memory process.
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Affiliation(s)
- M A M Banaclocha
- Department of Pathology, Hospital General de Castellón, Castellón, Spain.
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Creim JA, Lovely RH, Miller DL, Anderson LE. Rats can discriminate illuminance, but not magnetic fields, as a stimulus for learning a two-choice discrimination. Bioelectromagnetics 2002; 23:545-9. [PMID: 12224059 DOI: 10.1002/bem.10052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In each of the two experiments, nine rats were trained for 64 trials (eight trials per day) to determine if they could acquire a two-choice discrimination based on a specified discriminative stimulus (S(D)). In one experiment, the S(D) was a change in ambient illumination, while in the second experiment the S(D) was a change in the combination of sinusoidal 60 Hz and static magnetic field (MF) and any cues attendant to energizing the coils that produced the MF exposure. The rats that had a change in illuminance as the S(D) learned the two-choice task easily, P <.001, whereas the rats having a change in MFs as the S(D) did not.
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Affiliation(s)
- J A Creim
- Bioelectromagnetics Group, Molecular Biosciences Department, Pacific Northwest National Laboratory, PO Box 999, Richland, WA 99352, USA
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Abstract
To date, electric and magnetic exposure limits for frequencies below 100 kHz have been based on vaguely defined neurobiological responses to electric fields induced in tissues in vivo by magnetic fields and on perceptual responses to external electric fields. Advances in tissue dosimetry, risk assessment methods, and biological research on stimulation thresholds and mechanisms are providing new bases for exposure limits. This paper reviews the historical basis for current electric and magnetic exposure limits in preparation for the development of the "next generation" of electric and magnetic occupational and public exposure guidelines. This is followed by an overview of reported neurobiological effects of electric and magnetic stimulation that should be considered in new exposure guidelines. For magnetic fields, there is stronger evidence for setting exposure limits to protect against adverse effects of nerve stimulation than for protecting against visual magnetophosphenes. Magnetophosphenes are not adverse, and the evidence that these perceptual responses of the eye are a precursor or surrogate for other adverse neurologic responses is weak. Rather than relying just on theoretical models to set exposure limits, data from human subjects exposed to pulsed magnetic fields should be used to estimate nerve stimulation thresholds. Such data can provide a solid basis for setting magnetic field exposure limits if uncertainties in the data and inter-individual variability are addressed. Research on sensory perception, spontaneous and evoked potentials, and epidemiologic studies of neuropsychiatric conditions in electric and magnetic exposed populations does not suggest a need for lower exposure limits. However, a report that a 60-mT magnetic field (below the threshold for peripheral nerve stimulation) produces prolonged alterations of brain excitability and "indisposure" of subjects should be investigated in future research.
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Mostafa RM, Mostafa YM, Ennaceur A. Effects of exposure to extremely low-frequency magnetic field of 2 G intensity on memory and corticosterone level in rats. Physiol Behav 2002; 76:589-95. [PMID: 12126997 DOI: 10.1016/s0031-9384(02)00730-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
In the present study, we examined the effects of chronic exposure (1 and 2 weeks) to an extremely low-frequency magnetic field (ELFMF) of 2 G intensity on memory in rats using an object recognition task. Comparable groups of rats were exposed for 1, 2 or 4 weeks to ELFMF and the following day blood samples were collected from each rat for the measurement of corticosterone level. Our results demonstrate that exposure to ELFMF induces a significant increase in the level of corticosterone in blood plasma and is associated with impairment in discrimination between familiar and novel objects.
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Affiliation(s)
- Randa M Mostafa
- Zagazig University, Banha School of Medicine, Department of Physiology, Banha, Egypt
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