Home
Medical/biological study (experimental study)

Repeated exposure to low-level extremely low frequency-modulated microwaves affects cortex-hypothalamus interplay in freely moving rats: EEG study.

Published in: Int J Radiat Biol 2010; 86 (5): 376-383

Aim of study (acc. to author)

To compare the effects of repeated exposure to extremely low frequency-modulated microwaves on cortical and hypothalamic electroencephalograms (EEGs) of freely moving rats.
Background/further details: The EEGs were recorded for five consecutive days either under sham exposures (five rats) or under mixed sham exposure/microwave exposures (five rats).

Endpoint

Exposure

Exposure Parameters
Exposure 1: 915 MHz
Modulation type: FM, pulsed
Exposure duration: intermittently: 1 min on - 1 min off - for 10 min, 3 times per day for 3 days during a 5 day period (see "additional information")
Exposure 1
Main characteristics
Frequency 915 MHz
Type
Polarization
Exposure duration intermittently: 1 min on - 1 min off - for 10 min, 3 times per day for 3 days during a 5 day period (see "additional information")
Modulation
Modulation type FM, pulsed
Modulation frequency 4 Hz
Pulse width 20 ms
Exposure setup
Exposure source
  • circular wire antenna with a diameter of 18 cm
Distance between exposed object and exposure source 25 cm
Setup 15 cm x 17 cm x 30 cm Plexiglas box placed in an anechoic chamber lined with pyramidal Eccosorb; antenna fixed in the horizontal plane outside and above the box
Sham exposure A sham exposure was conducted.
Additional info 10 min pre- and post-exposure periods exposure group: sham exposure on day 1 and day 4, MW exposure on days 2, 3 and 5 sham group: sham exposure on all five days remark of the EMF-Portal editor: exposure time was differently described in the method section, the figures and the results of this article
Parameters
Measurand Value Type Method Mass Remarks
power density density 0.3 mW/cm² average over time measured - at a distance of 30 cm from the antenna
SAR 0.7 mW/g - - - -
Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated material:
Investigated organ system:
Time of investigation:
  • before exposure
  • during exposure
  • after exposure

Main outcome of study (acc. to author)

Extremely low frequency-modulated microwaves increased beta wave2 activity (17.8-30.5 Hz) in both cortical and hypothalamic EEG. Moreover, a cumulative effect under repeated exposures to extremely low frequency-modulated microwaves was found.
In conclusion, the data are in line with evidence that repeated low-level exposure to extremely low frequency-modulated microwaves affects brain functioning and provide an additional approach when analysing underlying mechanisms.
Study character:

Study funded by

  • Ministry for Science and Technology Development, Serbia

Related articles

  • Hidisoglu E et al. (2016): 2100-MHz electromagnetic fields have different effects on visual evoked potentials and oxidant/antioxidant status depending on exposure duration.
  • Li HJ et al. (2015): Alterations of cognitive function and 5-HT system in rats after long term microwave exposure.
  • Xie T et al. (2011): EEG changes as heat stress reactions in rats irradiated by high intensity 35 GHz millimeter waves.
  • Vorobyov V et al. (2009): Agroclavine potentiates hippocampal EEG effects of weak combined magnetic field in rats.
  • Lopez-Martin E et al. (2009): The action of pulse-modulated GSM radiation increases regional changes in brain activity and c-Fos expression in cortical and subcortical areas in a rat model of picrotoxin-induced seizure proneness.
  • Vecchio F et al. (2007): Mobile phone emission modulates interhemispheric functional coupling of EEG alpha rhythms.
  • Lopez-Martin E et al. (2006): GSM radiation triggers seizures and increases cerebral c-Fos positivity in rats pretreated with subconvulsive doses of picrotoxin.
  • Barcal J et al. (2005): Effect of whole-body exposure to high-frequency electromagnetic field on the brain electrogeny in neurodefective and healthy mice.
  • Vorobyov V et al. (2004): Repeated exposure to low-level extremely low frequency-modulated microwaves affects baseline and scopolamine-modified electroencephalograms in freely moving rats.
  • Hinrikus H et al. (2004): Changes in human EEG caused by low level modulated microwave stimulation.
  • Mausset-Bonnefont AL et al. (2004): Acute exposure to GSM 900-MHz electromagnetic fields induces glial reactivity and biochemical modifications in the rat brain.
  • Marino AA et al. (2003): Nonlinear changes in brain electrical activity due to cell phone radiation.
  • Vorobyov VV et al. (1997): Effects of weak microwave fields amplitude modulated at ELF on EEG of symmetric brain areas in rats.