Study type: Medical/biological study (experimental study)

Effects of weak microwave fields amplitude modulated at ELF on EEG of symmetric brain areas in rats. med./bio.

Published in: Bioelectromagnetics 1997; 18 (4): 293-298

Aim of study (acc. to author)

To study dependence of the EEG frequency spectra of symmetrical areas of the rat brain on exposure duration of the weak microwave field amplitude modulated at extremely low frequency (ELF).

Endpoint

Exposure

Exposure Parameters
Exposure 1: 945 MHz
Modulation type: AM
Exposure duration: intermittent, 1 min on/1 min off for 10 min

Exposure 1

Main characteristics
Frequency 945 MHz
Type
Exposure duration intermittent, 1 min on/1 min off for 10 min
Modulation
Modulation type AM
Modulation frequency 4 Hz
Additional info

20 ms pulse width

Exposure setup
Exposure source
Distance between exposed object and exposure source 30 cm
Setup Animals kept in the plexiglas box ( 17 x 11 x 20 cm) which was kept in the anechoic chamber.
Additional info Rats with chronically implanted carbon electrodes in the symmetrical areas of the brain somesthetic cortex, a reference carbon electrode placed in the nasal bone.
Parameters
Measurand Value Type Method Mass Remarks
power density 0.2 mW/cm² maximum unspecified - to 0.1 mW/cm²

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

The hemispheric asymmetry in baseline EEG is identical in both the control and exposure experiments when the frequency spectra are averaged for 10-min period. The similarity between series is observed also in the successive 10-min periods. Thus, the irradiation does not cause any steady changes in the EEG asymmetry during the 10-min periods. A similar conclusion can be drawn from averaging the EEG frequency spectra for 1-min "field-on" and "field-off" periods. The influence of the microwave field on the EEG asymmetry was revealed when averaging of frequency spectra for 10-s periods was used. Compared to controls, the EEG hemispheric asymmetry in power of 10.5-14 Hz range increases significantly during the first 10-20 s after four from five onsets of the field. Under neither control nor pre- and postexposure conditions this effects was found. These data are discussed with respect to interaction of microwave fields with the EEG generators.

Study character:

Study funded by

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