Effects of 45-Hz magnetic fields on the functional state of the human brain

Effects of Near-Infrared Pulsed Light on the Attention of Human Beings Using Electroencephalography

In our previous studies, photobiomodulation (PBM) stimulation can induce significant brain activation in normal subjects. In an open-eye study, the PBM stimulation was able to increase the power of alpha rhythms and theta waves, as well as decrease the beta activities after PBM stimulation. However, in the closed eyes study, the alpha rhythms in the laser group were reduced. This means the PBM stimulation can induce specific brainwaves under different conditions. Thus, to investigate the effects of PBM stimulation on human's attention, forty students were recruited in this single-blind randomized trial. A PBM stimulator, with seven pcs laser diodes (LDs), frequency 10 Hz, 30 mW/each LD, and wavelength 830 nm, was used to radiate the palm of the subject. PBM stimulation was found to induce significant variation in beta activity in most of the regions of the brain in the laser group. Compared to the placebo group, the PBM stimulation has a significant change in beta activity on electroencephalography (EEG). Three types of tests, the random number test, the Stroop color-word test, and the Multiple-Dimension Attention Test (MDAT), were used to evaluate the effects of the PBM stimulation. The scores of MDAT in the laser group increased more significantly than those in the placebo group after PBM stimulation (p < 0.01). An improvement in attention was observed in this study.

Grid Frequency Measurement through a PLHR Analysis Obtained from an ELF Magnetometer

The stability of the power grid’s frequency is crucial for industrial, commercial, and domestic applications. The standard frequency in Europe’s grid is 50 Hz and it must be as stable as possible; therefore, reliable measurement is essential to ensure that the frequency is within the limits defined in the standard EN 50160:2010. In this article, a method has been introduced for the measurement of the grid frequency through a power line harmonics radiation analysis. An extremely low-frequency magnetometer was developed with the specific purpose of monitoring, in real time, the electromagnetic field produced by electrical installations in the range from 0 to 2.2 kHz. Zero-crossing and Fast Fourier transform algorithms were applied to the output signal to calculate the grid frequency as a non-invasive method. As a final step, data for a complete month (May 2021) were compared with a commercial power quality analyzer connected to the main line to validate the results. The zero-crossing algorithm gave the best result on 3 May 2021, with a coefficient of determination (R²) of 0.9801. Therefore, the indirect measurement of the grid frequency obtained through this analysis satisfactorily fits the grid frequency.

Effect of Near-Infrared Pulsed Light on the Human Brain Using Electroencephalography

In our previous study, the low-level laser (LLL) stimulation at the palm with a stimulation frequency of 10 Hz was able to induce significant brain activation in normal subjects. The electroencephalography (EEG) changes caused by the stimulation of light-emitting diode (LED) in normal subjects have not been investigated. This study aimed at identifying the effects of LED stimulation on the human brain using EEG analysis. Moreover, the dosage has been raised 4 times than that in the previous LLL study. The LED array stimulator (6 pcs LEDs, central wavelength 850 nm, output power 30 mW, and operating frequency 10 Hz) was used as the stimulation source. The LED stimulation was found to induce significant variation in alpha activity in the occipital, parietal, and temporal regions of the brain. Compared to the previous low-level laser study, LED has similar effects on EEG in alpha (8–12 Hz) activity. Theta (4–7 Hz) power significantly increased in the posterior head region of the brain. The effect lasted for at least 15 minutes after stimulation ceased. Conversely, beta (13–35 Hz) intensity in the right parietal area increased significantly, and a biphasic dose response has been observed in this study.

Progress in the Knowledge, Application and Influence of Extremely Low Frequency Signals

This paper describes the characteristics of contributions made by researchers worldwide in the field of ELF (extremely low frequency) waves from 1957 to 2019. The data were collected through the Scopus database and processed with analytical and bibliometric techniques. The selection of the keywords is an essential step, because ELF has a very different meaning in some areas of medicine, where it is associated with a gene. A total of 12,436 documents were worked on in 12 thematic communities according to their collaborative relationships between authors and documents. Studies included authors publishing in the different thematic areas and the country where the USA stands first with more researchers in this theme than China and Japan. Documents were analyzed from the temporal perspective, their overall contribution, means of publication, and the language of the publication. Research requires extra effort and multidisciplinary collaboration to improve the knowledge, the application, and influence of these fields.

Behavioral testing of mice exposed to intermediate frequency magnetic fields indicates mild memory impairment

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.

Effects of A 60 Hz Magnetic Field of Up to 50 milliTesla on Human Tremor and EEG: A Pilot Study

Humans are surrounded by sources of daily exposure to power-frequency (60 Hz in North America) magnetic fields (MFs). Such time-varying MFs induce electric fields and currents in living structures which possibly lead to biological effects. The present pilot study examined possible extremely low frequency (ELF) MF effects on human neuromotor control in general, and physiological postural tremor and electroencephalography (EEG) in particular. Since the EEG cortical mu-rhythm (8–12 Hz) from the primary motor cortex and physiological tremor are related, it was hypothesized that a 60 Hz MF exposure focused on this cortical region could acutely modulate human physiological tremor. Ten healthy volunteers (age: 23.8 ± 4 SD) were fitted with a MRI-compatible EEG cap while exposed to 11 MF conditions (60 Hz, 0 to 50 mT_rms, 5 mT_rms increments). Simultaneously, physiological tremor (recorded from the contralateral index finger) and EEG (from associated motor and somatosensory brain regions) were measured. Results showed no significant main effect of MF exposure conditions on any of the analyzed physiological tremor characteristics. In terms of EEG, no significant effects of the MF were observed for C1, C3, C5 and CP1 electrodes. However, a significant main effect was found for CP3 and CP5 electrodes, both suggesting a decreased mu-rhythm spectral power with increasing MF flux density. This is however not confirmed by Bonferroni corrected pairwise comparisons. Considering both EEG and tremor findings, no effect of the MF exposure on human motor control was observed. However, MF exposure had a subtle effect on the mu-rhythm amplitude in the brain region involved in tactile perception. Current findings are to be considered with caution due to the small size of this pilot work, but they provide preliminary insights to international agencies establishing guidelines regarding electromagnetic field exposure with new experimental data acquired in humans exposed to high mT-range MFs.

Effects of a 60 Hz Magnetic Field Exposure Up to 3000 μT on Human Brain Activation as Measured by Functional Magnetic Resonance Imaging

Several aspects of the human nervous system and associated motor and cognitive processes have been reported to be modulated by extremely low-frequency (ELF, < 300 Hz) time-varying Magnetic Fields (MF). Due do their worldwide prevalence; power-line frequencies (60 Hz in North America) are of particular interest. Despite intense research efforts over the last few decades, the potential effects of 60 Hz MF still need to be elucidated, and the underlying mechanisms to be understood. In this study, we have used functional Magnetic Resonance Imaging (fMRI) to characterize potential changes in functional brain activation following human exposure to a 60 Hz MF through motor and cognitive tasks. First, pilot results acquired in a first set of subjects (N=9) were used to demonstrate the technical feasibility of using fMRI to detect subtle changes in functional brain activation with 60 Hz MF exposure at 1800 μT. Second, a full study involving a larger cohort of subjects tested brain activation during 1) a finger tapping task (N=20), and 2) a mental rotation task (N=21); before and after a one-hour, 60 Hz, 3000 μT MF exposure. The results indicate significant changes in task-induced functional brain activation as a consequence of MF exposure. However, no impact on task performance was found. These results illustrate the potential of using fMRI to identify MF-induced changes in functional brain activation, suggesting that a one-hour 60 Hz, 3000 μT MF exposure can modulate activity in specific brain regions after the end of the exposure period (i.e., residual effects). We discuss the possibility that MF exposure at 60 Hz, 3000 μT may be capable of modulating cortical excitability via a modulation of synaptic plasticity processes.

Improvement of neurofeedback therapy for improved attention through facilitation of brain activity using local sinusoidal extremely low frequency magnetic field exposure

Traditional neurofeedback (NF) is a training approach aimed at altering brain activity using electroencephalography (EEG) rhythms as feedback. In NF training, external factors such as the subjects' intelligence can have an effect. In contrast, a low-energy NF system (LENS) does not require conscious effort from the subject, which results in fewer attendance sessions. However, eliminating the subject role seems to eliminate an important part of the NF system. This study investigated the facilitating effect on the theta-to-beta ratio from NF training, using a local sinusoidal extremely low frequency magnetic field (LSELF-MF) versus traditional NF. Twenty-four healthy, intelligent subjects underwent 10 training sessions to enhance beta (15-18 Hz), and simultaneously inhibit theta (4-7 Hz) and high beta (22-30 Hz) activity, at the Cz point in a 3-boat-race video game. Each session consisted of 3 statuses, PRE, DURING, and POST. In the DURING status, the NF training procedure lasted 10 minutes. Subjects were led to believe that they would be exposed to a magnetic field during NF training; however, 16 of the subjects who were assigned to the experimental group were really exposed to 45 Hz-360 µT LSELF-MF at Cz. For the 8 other subjects, only the coil was located at the Cz point with no exposure. The duty cycle of exposure was 40% (2-second exposure and 3-second pause). The results show that the theta-to-beta ratio in the DURING status of each group differs significantly from the PRE and POST statuses. Between-group analysis shows that the theta-to-beta ratio in the DURING status of the experimental group is significantly (P < .001) lower than in the sham group. The result shows the effect of LSELF-MF on NF training.

Effects of two different waveforms of ELF MF on bioelectrical activity of antennal lobe neurons of Morimus funereus (Insecta, Coleoptera)

PURPOSE

External magnetic fields (MF) interact with organisms at all levels, including the nervous system. Bioelectrical activity of antennal lobe neurons of adult Morimus funereus was analyzed under the influence of extremely low frequency MF (ELF MF, 50 Hz, 2 mT) of different characteristics (exposure duration and waveform).

MATERIAL AND METHODS

Neuronal activity (background/neuronal population and those nearest to the recording electrode) in adult longhorn beetles was registered through several phases of exposure to the sine wave and square wave MF for 5, 10 and 15 min.

RESULTS

The sine wave MF, regardless of the exposure duration, did not change the reversibility factor of antennal lobe neuronal activity in adult M. funereus. In contrast, reversibility factors of the nearest neurons were significantly changed after the exposure to square wave MF for 10 and 15 min.

CONCLUSION

M. funereus individuals are sensitive to both sine wave and square wave ELF MF (50 Hz, 2 mT) of different duration, whereby their reactions depend on the characteristics of the applied MF and specificity of each individual.

Effects of extremely low-frequency magnetic fields on the response of a conductance-based neuron model

To provide insights into the modulation of neuronal activity by extremely low-frequency (ELF) magnetic field (MF), we present a conductance-based neuron model and introduce ELF sinusoidal MF as an additive voltage input. By analyzing spike times and spiking frequency, it is observed that neuron with distinct spiking patterns exhibits different response properties in the presence of MF exposure. For tonic spiking neuron, the perturbations of MF exposure on spike times is maximized at the harmonics of neuronal intrinsic spiking frequency, while it is maximized at the harmonics of bursting frequency for burst spiking neuron. As MF intensity increases, the perturbations also increase. Compared with tonic spiking, bursting dynamics are less sensitive to the perturbations of ELF MF exposure. Further, ELF MF exposure is more prone to perturb neuronal spike times relative to spiking frequency. Our finding suggests that the resonance may be one of the neural mechanisms underlying the modulatory effects of the low-intensity ELF MFs on neuronal activities. The results highlight the impacts of ELF MFs exposure on neuronal activity from the single cell level, and demonstrate various factors including ELF MF properties and neuronal spiking characteristics could determine the outcome of exposure. These insights into the mechanism of MF exposure may be relevant for the design of multi-intensity magnetic stimulus protocols, and may even contribute to the interpretation of MF effects on the central nervous systems.

Effects of extremely low frequency electromagnetic field (50 Hz) on pentylenetetrazol-induced seizures in mice

The electromagnetic fields (EMF) have various behavioral and biological effects on human body. There are growing concerns about the consequences of exposure to EMF. However, some studies have shown beneficial effects of these waves on human. In this paper, we study the effect of acute, sub acute and long-term exposure to 50 Hz, 0.1 mT magnetic fields (MF) on the seizure induction threshold in mice. 64 mice are used and divided into four groups. Eight mice in any group were selected to be exposed to MF for specific duration and the others were used as a control group. The duration of the applied exposures was as follows: (1) 1 day (acute), (2) 3 days (sub acute), (3) 2 weeks (sub acute), (4) 1 month (long term). The mice were exposed 2 h for a day. After exposure, the pentylentetrazol (PTZ) is injected to the mice to induce seizure and the needed dose for the seizure induction threshold is measured. In the acute exposure, the threshold to induce seizure in the exposed and sham-exposed groups was 44.25 and 46.5 mg, respectively, while the difference was not significant (p value = 0.5). In the sub acute exposure (3 days), the mean amount of drug to induce seizure was 47.38 mg in the exposed and 43.88 mg in the sham-exposed groups, however, the difference was not significant (p value = 0.3). The results were 52.38 and 46.75 mg after 2 weeks of exposure which were not significantly different either (p value = 0.2). After 1 month of exposure to MF, the threshold for the induction of seizure was significantly increased (p value < 0.05). The mean dosage to induce seizure in the exposed and control group was 54.3 and 45.75 mg, respectively. However, considering the p value, the difference in the seizure induction threshold between the exposed and sham-exposed groups after acute and sub acute exposure was not significant, analyzing the effects of acute, sub acute and long-term exposures totally indicates that increasing the exposure time increases the seizure induction threshold.

Influence of magnetic field on brain activity during administration of caffeine

The aim of the present work is to evaluate the effect of caffeine, the world's most popular psychoactive drug, on the electric activity of the rat's brain that exposed to extremely low-frequency magnetic field (ELF-MF), during 15 days. The obtained results showed that administration of caffeine in a group of rats by dose of 10 mg/kg (equivalent to human daily consumption) caused a reduction in the mean power amplitude of electroencephalogram (EEG) trace for almost all frequency bands especially α (8-12 Hz). It was observed that the influence of caffeine was more evident in motor cortex than in visual cortex. While the exposure of another group to ELF-MF of intensity 0.2 mT during the same period caused an enhancement in the mean power amplitude of most EEG frequency bands; this was more observed in the right hemisphere of the brain than that of the left hemisphere. The administration of caffeine while rats were exposed to ELF-MF, led, after 5 days of exposure, to a great increase in the mean power amplitude of α band at all places of recording electrodes. It may be concluded that caffeine administration was more effective in reducing the hazardous of ELF-MF in motor cortex than in visual cortex.

A consensus panel review of central nervous system effects of the exposure to low-intensity extremely low-frequency magnetic fields

BACKGROUND

A large number of studies explored the biological effects of extremely low-frequency (0-300 Hz) magnetic fields (ELF-MFs) on nervous system both at cellular and at system level in the intact human brain reporting several functional changes. However, the results of different studies are quite variable and the mechanisms of action of ELF-MFs are still poorly defined. The aim of this paper is to provide a comprehensive review of the effects of ELF-MFs on nervous system.

METHODS

We convened a workgroup of researchers in the field to review and discuss the available data about the nervous system effects produced by the exposure to ELF-MFs.

MAIN FINDINGS/DISCUSSION

We reviewed several methodological, experimental and clinical studies and discussed the findings in five sections. The first section analyses the devices used for ELF-MF exposure. The second section reviews the contribution of the computational methods and models for investigating the interaction between ELF-MFs and neuronal systems. The third section analyses the experimental data at cellular and tissue level showing the effects on cell membrane receptors and intracellular signaling and their correlation with neural stem cell proliferation and differentiation. The fourth section reviews the studies performed in the intact human brain evaluating the changes produced by ELF-MFs using neurophysiological and neuropsychological methods. The last section shows the limits and shortcomings of the available data, evidences the key challenges in the field and tracks directions for future research.

Effect of Low-Level Laser Stimulation on EEG Power in Normal Subjects with Closed Eyes

In a previous study, we found that the low-level laser (LLL) stimulation at the palm with a frequency of 10 Hz was able to induce significant brain activation in normal subjects with opened eyes. However, the electroencephalography (EEG) changes to LLL stimulation in subjects with closed eyes have not been studied. In the present study, the laser array stimulator was applied to deliver insensible laser stimulations to the palm of the tested subjects with closed eyes (the laser group). The EEG activities before, during, and after the laser stimulation were collected. The EEG amplitude powers of each EEG frequency band at 19 locations were calculated. These power data were then analyzed by SPSS software using repeated-measure ANOVAs and appropriate posthoc tests. We found a pronounced decrease in the EEG power in alpha-bandwidth during laser simulation and then less decrease in the EEG power in delta-bandwidth in normal subjects with laser stimulation. The EEG power in beta-bandwidth in the right occipital area also decreased significantly in the laser group. We suggest that LLL stimulation might be conducive to falling into sleep in patients with sleep problems.

Effect of low-level laser stimulation on EEG

Conventional laser stimulation at the acupoint can induce significant brain activation, and the activation is theoretically conveyed by the sensory afferents. Whether the insensible low-level Laser stimulation outside the acupoint could also evoke electroencephalographic (EEG) changes is not known. We designed a low-level laser array stimulator (6 pcs laser diode, wavelength 830 nm, output power 7 mW, and operation frequency 10 Hz) to deliver insensible laser stimulations to the palm. EEG activities before, during, and after the laser stimulation were collected. The amplitude powers of each EEG frequency band were analyzed. We found that the low-level laser stimulation was able to increase the power of alpha rhythms and theta waves, mainly in the posterior head regions. These effects lasted at least 15 minutes after cessation of the laser stimulation. The amplitude power of beta activities in the anterior head regions decreased after laser stimulation. We thought these EEG changes comparable to those in meditation.

Exposure to extremely low frequency magnetic fields induces fos-related antigen-immunoreactivity via activation of dopaminergic d1 receptor

We previously demonstrated that repeated exposure to extremely low frequency magnetic fields (ELF-MF) increases locomotor activity via stimulation of dopaminergic D1 receptor (J. Pharmacol. Sci., 2007;105:367-371). Since it has been demonstrated that activator protein-1 (AP-1) transcription factors, especially 35-kDa fos-related antigen (FRA), play a key role in the neuronal and behavioral adaptation in response to various stimuli, we examined whether repeated ELF-MF exposure induces FRA-immunoreactivity (FRA-IR) in the striatum and nucleus accumbens (striatal complex) of the mice. Repeated exposure to ELF-MF (0.3 or 2.4 mT, 1 h/day, for consecutive fourteen days) significantly induced hyperlocomotor activity and FRA-IR in the striatal complex in a field intensity-dependent manner. ELF-MF-induced FRA-IR lasted for at least 1 year, while locomotor activity returned near control level 3 months after the final exposure to ELF-MF. Pretreatment with SCH23390, a dopaminergic D1 receptor antagonist, but not with sulpiride, a dopaminergic D2 receptor antagonist, significantly attenuated hyperlocomotor activity and FRA-IR induced by ELF-MF. Our results suggest that repeated exposure to ELF-MF leads to prolonged locomotor stimulation and long-term expression of FRA in the striatal complex of the mice via stimulation of dopaminergic D1 receptor.

Neurophysiological and behavioral effects of a 60 Hz, 1,800 μT magnetic field in humans

The effects of time-varying magnetic fields (MF) on humans have been actively investigated for the past three decades. One important unanswered question is the potential for MF exposure to have acute effects on human biology. Different strategies have been used to tackle this question using various physiological, neurophysiological and behavioral indicators. For example, researchers investigating electroencephalography (EEG) have reported that extremely low frequency (ELF, <300 Hz) MF can increase resting occipital alpha rhythm (8-12 Hz). Interestingly, other studies have demonstrated that human motricity can be modulated by ELF MF: a reduction of anteroposterior standing balance or a decrease of physiological tremor intensity have been reported as consequences of exposure. However, the main limitation in this domain lies in the lack of results replication, possibly originating from the large variety of experimental approaches employed. Therefore, the present study aimed to investigate the effects of a 60 Hz, 1,800 μT MF exposure on neurophysiological (EEG) and neuromotor (standing balance, voluntary motor function, and physiological tremor) aspects in humans using a single experimental procedure. Though results from this study suggest a reduction of human standing balance with MF exposure, as well as an increase of physiological tremor amplitude within the frequency range associated with central nervous system contribution, no exposure effect appeared on other investigated parameters (e.g., EEG or voluntary motor control). These results suggest that 1 h of 60 Hz, 1,800 μT MF exposure may modulate human involuntary motor control without being detected in the cortical electrical activity.

Effects of extremely low-frequency magnetic field exposure on cognitive functions: results of a meta-analysis

There is extensive literature on possible effects of extremely low-frequency magnetic fields (ELF-MFs) on human cognitive functions. However, due to methodological deficits (e.g., low statistical power, small sample sizes) findings have been inconsistent. In the current study we try to overcome these problems by carrying out a meta-analysis. Literature research revealed 17 studies. Nine of these were included in the meta-analysis because they fulfilled minimum requirements (e.g., at least single-blind experimental study design and documentation of means and standard deviation of the dependent variables). All of the studies used a 50 Hz magnetic field exposure. Small but significant effect sizes could be detected in two cognitive dimensions: in the hard level of visual duration discrimination, task-exposed subjects performed better than controls; at the intermediate level however, exposed subjects performed worse. Additionally, a significant improvement of correct responses was observed in the dimension of "flexibility" under exposure. However, due to the small number of studies per performance dimensions and the resulting instability of estimates, these findings have to be treated with extreme caution. Taken together, the results of the meta-analysis provide little evidence that ELF-MFs have any effects on cognitive functions.

Therapeutic efficacy assessment of weak variable magnetic fields with low value of induction in patients with drug-resistant depression

BACKGROUND

The aim of this prospective study was to verify whether magnetostimulation with weak variable magnetic fields with low value of induction could enhance the effects of pharmacological therapy in drug-resistant depression.

MATERIALS AND METHODS

Thirty patients, 26 women and 4 men, with drug-resistant depression were enrolled in the study. The subjects from Group No. I (14 patients) were given fluvoxamine and treated with weak variable magnetic field using the VIOFOR JPS device; the subjects from Group No. II (16 patients) were also given fluvoxamine but they were treated with the VIOFOR JPS device in placebo mode. Changes in depressive symptoms were estimated with the 21-point Hamilton Depression Scale (HDRS), Montgomery-Asberg Depression Scale (MADRS) and Beck Depression Inventory (BDI) questionnaire.

RESULTS

After 15 days of treatment highly significant differences were revealed between the patients treated with magnetic field and the patients treated with placebo: the final HDRS score was 53% of the initial value for the group receiving combined treatment, and 86% in the placebo group (p<0.001); for MADRS score the values were 51% and 88% (p<0.001), respectively, and for BDI 60% and 87% (p<0.001). Thus, the average effect of placebo applied with fluvoxamine was a ca. 15% reduction of symptoms, while the concurrent application of magnetic field and SSRI treatment resulted in a 40-50% improvement.

CONCLUSION

Our study indicates that adding a two-week low-induction variable magnetic field stimulation to a classical pharmacologic therapy reduces the intensity of symptoms in patients with drug-resistant depressive disorders.

Does exposure to extremely low frequency magnetic fields produce functional changes in human brain?

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.

Investigations of a simulated geomagnetic field experienced by the International Space Station on attentional performance

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.

Electromagnetic effects - From cell biology to medicine

In this review we compile and discuss the published plethora of cell biological effects which are ascribed to electric fields (EF), magnetic fields (MF) and electromagnetic fields (EMF). In recent years, a change in paradigm took place concerning the endogenously produced static EF of cells and tissues. Here, modern molecular biology could link the action of ion transporters and ion channels to the "electric" action of cells and tissues. Also, sensing of these mainly EF could be demonstrated in studies of cell migration and wound healing. The triggers exerted by ion concentrations and concomitant electric field gradients have been traced along signaling cascades till gene expression changes in the nucleus. Far more enigmatic is the way of action of static MF which come in most cases from outside (e.g. earth magnetic field). All systems in an organism from the molecular to the organ level are more or less in motion. Thus, in living tissue we mostly find alternating fields as well as combination of EF and MF normally in the range of extremely low-frequency EMF. Because a bewildering array of model systems and clinical devices exits in the EMF field we concentrate on cell biological findings and look for basic principles in the EF, MF and EMF action. As an outlook for future research topics, this review tries to link areas of EF, MF and EMF research to thermodynamics and quantum physics, approaches that will produce novel insights into cell biology.

The autistic syndrome and endogenous ion cyclotron resonance: state of the art

The autistic syndrome is a multigenic disease whose expression is different according to the level of involvement of different structures in the central nervous system. The pathogenesis is unknown. No completely effective medical therapy has yet been demonstrated. Accepting the request of the families of eight autistic children in Lomazzo, Milan and Naples, we used ion cyclotron resonance (Seqex therapy) therapeutic support after many other therapies had been already carried out on these patients. After regimens consisting of 20-30 treatments with ICR, improvements were noted in all cases.

Neurophysiological effects of mobile phone electromagnetic fields on humans: a comprehensive review

In recent years a growing number of people have begun to use mobile phone technology. This phenomenon has raised questions and doubts about possible effects on users' brains. This literature review focuses on the human electrophysiological and neuro-metabolic effects of mobile phone (MP)-related electromagnetic fields (EMFs) published in the last 10 years. To this end, all relevant papers have been reported and, subsequently, a literature selection has been carried out by taking several criteria into account, such as: blind techniques, randomization or counter-balancing of conditions and subjects, detail of exposure characteristics and the statistical analyses used. As a result, only the studies meeting the selection criteria have been described, evaluated and discussed further. The main goal of this review is to provide a clear scenario of the most reliable experiments carried out over the last decade and to offer a critical point of view in their evaluation. It is concluded that MP-EMFs may influence normal physiology through changes in cortical excitability and that in future research particular care should be dedicated to both methodological and statistical control, the most relevant criteria in this research field.

Exposure to ELF magnetic and ELF-modulated radiofrequency fields: the time course of physiological and cognitive effects observed in recent studies (2001-2005)

In 2002, we published a review of the cognitive and physiological effects of extremely low frequency magnetic fields (ELF MFs) and ELF-modulated radiofrequency fields associated with mobile phones. Since the original preparation of that review, a significant number of studies have been published using techniques such as electroencephalography, event-related potentials and positron emission tomography to investigate electromagnetic field effects upon human physiology and various measures of performance (cognitive, perceptual, behavioral). We review these recent studies, and when effects were observed, we reference the time course of observed effects (immediate or delayed). In our concluding remarks, we discuss a number of variables that are not often considered in human bioelectromagnetics studies, such as personality, individual differences and the specific laterality of ELF MF and mobile phone exposure over the brain. We also consider the sensitivity of various physiological assays and performance measures in the study of biological effects of electromagnetic fields.

Association between high voltage overhead transmission lines and mental health: a cross-sectional study

We examined the association between residential proximity to 60 Hz high voltage (22-500 kV) overhead transmission lines (HVOTLs) and mental health (MH). The subjects were 223 mothers with a mean age of 37 years. The distance from the subject's residence to the closest HVOTL was measured on a map. MH status was assessed by the SF-36 Health Survey, which was scored on a 0-100 point scale, and an individual with a score of 52 points or less was defined as having poor MH. Logistic regression models were used to examine the association between the distance from the subjects' residence to the closest HVOTL and MH status. The prevalence of poor MH was 15%. Among the 223 subjects, 10 lived within 100 m of a HVOTL. The adjusted odds ratios (OR) for poor MH among those who lived 101-300 m or within 100 m from HVOTL were 1.29 (95% confidence interval (CI): 0.35-10.13) and 1.87 (95% CI: 0.35-10.13), respectively, against the reference category (300+ m). MH status was not significantly associated with the distance between the subject's residence and the closest HVOTL.

Effects of 50Hz electromagnetic fields on electroencephalographic alpha activity, dental pain threshold and cardiovascular parameters in humans

Recent studies indicate that exposure to extremely low frequency magnetic fields (ELF MFs) influences human electroencephalographic (EEG) alpha activity and pain perception. In the present study we analyse the effect on electrical EEG activity in the alpha band (8-13 Hz) and on nociception in 40 healthy male volunteers after 90-min exposure of the head to 50 Hz ELF MFs at a flux density of 40 or 80 microT in a double-blind randomized sham-controlled study. Since cardiovascular regulation is functionally related to pain modulation, we also measured blood pressure (BP) and heart rate (HR) during treatment. Alpha activity after 80 microT magnetic treatment almost doubled compared to sham treatment. Pain threshold after 40 microT magnetic treatment was significantly lower than after sham treatment. No effects were found for BP and HR. We suggest that these results may be explained by a modulation of sensory gating processes through the opioidergic system, that in turn is influenced by magnetic exposure.

Resting EEG effects during exposure to a pulsed ELF magnetic field

Continuing evidence suggests that extremely low frequency magnetic fields (ELF MFs) can affect animal and human behavior. We have previously demonstrated that after a 15 min exposure to a pulsed ELF MF, with most power at frequencies between 0 and 500 Hz, human brain electrical activity is affected as measured by electroencephalography (EEG), specifically within the alpha frequency (8-13 Hz). Here, we report that a pulsed ELF MF affects the human EEG during the exposure period. Twenty subjects (10 males; 10 females) received both a magnetic field and a sham session of 15 min in a counterbalanced design. Analysis of variance (ANOVA) revealed that alpha activity was significantly lower over the occipital electrodes (O1, Oz, O2) [F(1,16) = 5.376, P < .01, eta2 = 0.418] after the first 5 min of magnetic field exposure and was found to be related to the order of exposure (MF-sham vs. sham-MF). This decrease in alpha activity was no longer significant in the 1st min post-exposure, compared to sham (P > .05). This study is among the first to assess EEG frequency changes during a weak (+/-200 microTpk), pulsed ELF MF exposure.

Actions of pulsed ultra-broadband electromagnetic irradiation on the EEG and sleep in laboratory animals

Irradiation of animals with ultrashort impulses of ultra-broadband magnetic irradiation with an impulse repetition frequency of 6 Hz for 1 h induced changes in the spectral composition of cerebral cortex electrical activity in rats, measured over the 5 min immediately after irradiation, as compared with controls. In particular, there was suppression of frequencies close to the impulse sequence frequency, along with a decrease in interhemisphere coherence. Continuous recording of polygrams for 22 h from rabbits after irradiation revealed a "delayed" effect--a significant increase in paradoxical sleep, starting 16 h after the end of irradiation and persisting to the end of the recording period. It is suggested that irradiation has a direct action both on the mechanisms of generation of the theta rhythm (septohippocampal) and on the system controlling circadian rhythms (the suprachiasmatic nucleus-epiphysis system).

Neurobehavioural effects of electromagnetic fields

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.

Absence of daytime 50 Hz, 100 ?Trms magnetic field or bright light exposure effect on human performance and psychophysiological parameters

The purpose of this study was to reproduce and extend two earlier studies of the effects of human exposure to 50 Hz magnetic fields (MF). In a recent paper, we described results of two double-blind investigations performed to examine effects of 100 microT(rms) 50 Hz MF exposure on psychological parameters in the same group of healthy human volunteers. In each exposure session, at 1 week intervals, with sham, continuous, and intermittent (15 s ON/OFF cycles) MF conditions, mood ratings, performance measures, and electrophysiological measures were taken. In the first study, significant amplitude changes were observed in the event-related brain potentials (ERP) recorded during a dichotic listening task. In the second study, latency and reaction time (RT) slowing were seen on a visual discrimination task (P(300) paradigm). Although these results were little related to the number of parameters analysed, they indicate that low level 50 Hz MF might have a slight influence on ERP and RT under specific circumstances of sustained attention. Before concluding that moderately strong MF exposure can influence cognitive function, previous results should be replicated, using the same paradigms with another group of healthy volunteers. In the present study, 18 healthy subjects were exposed to three experimental sessions of 30 min each, given at 1 week intervals. The sessions consisted of continuous 100 microT(rms) 50 Hz MF exposure, sham condition, and bright light (5000 lux) exposure. The study was performed double-blind, with the exposure order counter-balanced. The data on mood, ERP, RT, and other performance measures did not show any differences among the sham exposure, light exposure, and MF exposure conditions. The results of this study do not support the hypothesis that extremely low frequency (ELF) MF exposure affects the brain's electrical activity or cognitive function at field strength (100 microT(rms)) similar to that found in very close proximity of some household and industrial electrical appliances and well in excess of the average MF strength (c. 0.1 microT) found in homes. The sensitivity of the experiment was possibly not sufficient to detect an effect at this relatively low MF, and larger sample sizes would be required in further studies.

No influence of 20 and 400 µT, 50 Hz magnetic field exposure on cognitive function in humans

The aim of the present study was to investigate cognitive effects of a continuous, vertical extremely low frequency (ELF) magnetic field (MF) of 20 and 400 microT 50 Hz in healthy young men during performance on cognitive tests. Thirty-two volunteers (20-30 years old, mean 22.6 +/- 2.2 years) participated in this double blind study. The test protocol consisted of a set of tests: divided attention, flexibility, memory updating, digit span, digit span with articulary suppression, and time perception. The total duration of the exposure was 65 min. Participants were assigned four sessions: three conditions in the helmet (sham exposure, 20 and 400 microT) and one condition out of the helmet (to control the expectancy effect). No effect of MF exposure was observed on performance.

Resting EEG is affected by exposure to a pulsed ELF magnetic field

An increasing number of reports have demonstrated a significant effect of extremely low frequency magnetic fields (ELF MFs) on aspects of animal and human behavior. Recent studies suggest that exposure to ELF MFs affects human brain electrical activity as measured by electroencephalography (EEG), specifically within the alpha frequency (8-13 Hz). Here we report that exposure to a pulsed ELF MF with most power at frequencies between 0 and 500 Hz, known to affect aspects of analgesia and standing balance, also affects the human EEG. Twenty subjects (10 males; 10 females) received both a magnetic field (MF) and a sham session in a counterbalanced design for 15 min. Analysis of variance (ANOVA) revealed that alpha activity was significantly higher over the occipital electrodes (O1, Oz, O2) [F(1,16) = 6.858; P =.019, eta2 = 0.30] and marginally higher over the parietal electrodes (P3, Pz, P4) [F(1,16) = 4.251; P =.056, eta2 = 0.21] post MF exposure. This enhancement of alpha activity was transient, as it marginally decreased over occipital [F(1,16) = 4.417; P =.052; eta2 = 0.216] and parietal electrodes [F(1,16) = 4.244; P =.056; eta2 = 0.21] approximately 7 min after MF exposure compared to the sham exposure. Significantly higher occipital alpha activity is consistent with other experiments examining EEG responses to ELF MFs and ELF modulated radiofrequency fields associated with mobile phones. Hence, we suggest that this result may be a nonspecific physiological response to the pulsed MFs.

Effect of low-frequency magnetic fields on brain electrical activity in human subjects

OBJECTIVE

To measure the response rate of normal human subjects to a low-strength, low-frequency magnetic field (MF), using nonlinear quantitative analysis of the electroencephalogram (EEG).

METHODS

Eight subjects were exposed to a series of trials, each consisting of the application of the MF (1 G, 60 Hz) for 2 s followed by a field-free period of 5 s, and the EEG was analyzed statistically using phase-space methods to assess whether the subject detected the MF.

RESULTS

Each subject exhibited statistically significant changes in the EEG during presentation of the MF, as evidenced by increases in percent determinism and percent recurrence, two different measures of deterministic structure in the recorded signal, thereby indicating that the MF had been detected.

CONCLUSIONS

The 100% response rate manifested by the study group suggested that the ability to detect low-strength, low-frequency MFs is a common property of the human nervous system.

Alternating extremely low frequency magnetic field increases turnover of dopamine and serotonin in rat frontal cortex

The aim of this study was to evaluate the influence of an extremely low frequency sinusoidal magnetic field (ELF MF) with frequency of 10 Hz and intensity of 1.8-3.8 mT on the levels of the biogenic amines dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), 3-methoxytyramine (3-MT), 5-hydroxytryptamine (5-HT), 5-hydroxyindolacetic acid (5-HIAA), and noradrenaline (NA), as well as on DA and 5-HT turnover in corpus striatum and frontal cortex of adult male Wistar rats. We found that ELF MF exposure for 14 days, 1 h daily, did not influence the level of the examined biogenic amines and metabolites, but increased the rate of synthesis (turnover) of DA and 5-HT in rat frontal cortex as compared to control, sham exposed rats. On the basis of the present results and our previous findings, extremely low frequency magnetic field (ELF MF) exposure has been found to alter both turnover and receptor reactivity of monoaminergic systems, as well as some behaviors induced by these systems or their agonists and antagonists.

Brief exposure to a 50 Hz, 100 microT magnetic field: effects on reaction time, accuracy, and recognition memory

The present study investigated both the direct and delayed effects of a 50 Hz, 100 microT magnetic field on human performance. Eighty subjects completed a visual duration discrimination task, half being exposed to the field and the other half sham exposed. The delayed effects of this field were also examined in a recognition memory task that followed immediately upon completion of the discrimination task, Unlike our earlier studies, we were unable to find any effects of the field on reaction time and accuracy in the visual discrimination task. However, the field had a delayed effect on memory, producing a decrement in recognition accuracy. We conclude that after many years of experimentation, finding a set of magnetic field parameters and human performance measures that reliably yield magnetic field effects is proving elusive. Yet the large number of significant findings suggests that further research is warranted.

Human electrophysiological and cognitive effects of exposure to ELF magnetic and ELF modulated RF and microwave fields: a review of recent studies

The investigation of weak (<500 microT), extremely low frequency (ELF, 0-300 Hz) magnetic field (MF) exposure upon human cognition and electrophysiology has yielded incomplete and contradictory evidence that MFs interact with human biology. This may be due to the small number of studies undertaken examining ELF MF effects upon the human electroencephalogram (EEG), and the associated analysis of evoked related potentials (ERPs). Relatively few studies have examined how MF exposure may affect cognitive and perceptual processing in human subjects. The introduction of this review considers some of the recent studies of ELF MF exposure upon the EEG, ERPs and cognitive and perceptual tasks. We also consider some of the confounding factors within current human MF studies and suggest some new strategies for further experimentation.