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Changes in synaptic efficacy and seizure susceptibility in rat brain slices following extremely low‐frequency electromagnetic field exposure

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Varró P, Szemerszky R, Bárdos G, Világi I. · 2009

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Extremely low-frequency EMF exposure altered synaptic activity in rat brain slices, with effects that appeared to be transient.

Plain English Summary

Summary written for general audiences

Researchers exposed whole rats or excised rat brain slices to a 50 Hz electromagnetic field at 250–500 µT to examine effects on synaptic efficacy in the central nervous system. Slices treated directly ex vivo showed a decrease in basic synaptic activity, observed as a diminution in amplitude of evoked potentials. Following whole-body exposure, enhanced short- and long-term synaptic facilitation in hippocampal slices and increased seizure susceptibility in neocortical slices were observed. The researchers noted that the overall changes may strongly depend on the synaptic structure and neuronal network of the affected region, together with the specific spatial parameters and constancy of the EMF.

Why This Matters

The study used electrophysiological investigation carried out ex vivo on neocortical and hippocampal slices, testing basic synaptic functions, short- and long-term plasticity, and seizure susceptibility. The direction of the synaptic changes differed depending on the exposure method: direct slice exposure reduced basic synaptic activity, while whole-body exposure enhanced facilitation. The researchers described the effects as transient and concluded that ELF-EMF exposure exerts significant effects on synaptic activity.

Exposure Details

Magnetic Field
0.25 - 0.5 mT
Source/Device
50 Hz

Exposure Context

This study used 0.25 - 0.5 mT for magnetic fields:

Building Biology guidelines are practitioner-based limits from real-world assessments. BioInitiative Report recommendations are based on peer-reviewed science. Check Your Exposure to compare your own measurements.

Where This Falls on the Concern Scale

Study Exposure Level in ContextStudy Exposure Level in ContextThis study: 0.25 - 0.5 mTExtreme Concern - 5 mGFCC Limit - 2,000 mGEffects observed in the Extreme Concern range (Building Biology)This level is 1 times the FCC limit
A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 50 Hz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 50 HzCell phones~1 GHzWiFi2.4 GHz5G mm28 GHzLogarithmic scale

Study Details

To study the Changes in synaptic efficacy and seizure susceptibility in rat brain slices following extremely low‐frequency electromagnetic field exposure

In the present series of experiments, whole rats or excised rat brain slices were exposed to a refer...

The most pronounced effect was a decrease in basic synaptic activity in slices treated directly ex v...

We can conclude that ELF‐EMF exposure exerts significant effects on synaptic activity, but the overall changes may strongly depend on the synaptic structure and neuronal network of the affected region together with the specific spatial parameters and constancy of EMF.

Cite This Study
Varró P, Szemerszky R, Bárdos G, Világi I. (2009). Changes in synaptic efficacy and seizure susceptibility in rat brain slices following extremely low‐frequency electromagnetic field exposure Bioelectromagnetics. 30(8):631-640, 2009.
Show BibTeX
@article{p_2009_changes_in_synaptic_efficacy_309,
  author = {Varró P and Szemerszky R and Bárdos G and Világi I.},
  title = {Changes in synaptic efficacy and seizure susceptibility in rat brain slices following extremely low‐frequency electromagnetic field exposure},
  year = {2009},
  doi = {10.1002/bem.20517},
  url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/bem.20517},
}
DOI: 10.1002/bem.20517

Cited By (35 papers)

Quick Questions About This Study

The study used a 50 Hz electromagnetic field at a reference level intensity of 250–500 µT.
Directly exposed slices showed a decrease in basic synaptic activity, seen as a diminution in amplitude of evoked potentials.
Whole-body exposure was associated with enhanced short- and long-term synaptic facilitation in hippocampal slices and increased seizure susceptibility in neocortical slices.
The researchers noted that the effects seem to be transient.
Researchers concluded that ELF-EMF exposure exerts significant effects on synaptic activity, but that the overall changes may strongly depend on the synaptic structure and neuronal network of the affected region.