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 med./bio.

By: Vorobyov V, Janac B, Pesic V, Prolic Z

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

effects on the neurological system: functioning/activation of different brain areas (EEG)

Exposure

- low level microwaves
- TDMA
- PW pulsed wave
- mobile communications

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")	power density: 0.3 mW/cm² average over time (at a distance of 30 cm from the antenna) SAR: 0.7 mW/g

Exposure 1

Main characteristics

Frequency	915 MHz
Type	electromagnetic field
Polarization	linear
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	0.3 mW/cm²	average over time	measured	-	at a distance of 30 cm from the antenna
SAR	0.7 mW/g	-	-	-	-

Exposed system:

animal
rat/Wistar
whole body

Methods Endpoint/measurement parameters/methodology

effects on the neurological system: EEG (averaged frequency spectra 0.5-30 Hz)

Investigated system:

investigation on living organism

Investigated organ system:

brain/CNS

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:

medical/biological study
experimental study
full/main study

Study funded by

Ministry for Science and Technology Development, Serbia

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