Study type: Medical/biological study (experimental study)

Operant behavior and colonic temperature of Macaca mulatta exposed to radio frequency fields at and above resonant frequencies. med./bio.

Published in: Bioelectromagnetics 1984; 5 (2): 233-246

Aim of study (acc. to author)

To study operant behavior and colonic temperature of rhesus monkeys exposed to radiofrequency fields and to determine the minimal power densities affecting performance.

Background/further details

The animals were trained to press a lever (observing-response) thereby producing signals that indicated availability of food. In the presence of the aperiodically appearing food signals, a detection response on a different lever was reinforced by food.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 255 MHz
Modulation type: CW
Exposure duration: continuous for 60 min/session; 53 sessions altogather
Exposure 2: 1.3 GHz
Modulation type: pulsed
Exposure duration: continuous for 60 min/session, 328 sessions altogather
Exposure 3: 5.8 GHz
Modulation type: pulsed
Exposure duration: continuous for 60 min/session; 133 sessions altogather

Exposure 1

Main characteristics
Frequency 255 MHz
Charakteristic
Exposure duration continuous for 60 min/session; 53 sessions altogather
Modulation
Modulation type CW
Exposure setup
Exposure source
Distance between exposed object and exposure source 0.24 m
Chamber Anechoic chamber shielded by metal.
Setup Animals were restrained in chairs and their heads were aligned with the center of the horn.
Additional info Animal was 0.78 times the far-field distance.
Parameters
Measurand Value Type Method Mass Remarks
power density 50 W/m² minimum measured - to 11 mW/cm²
power density 81 W/m² mean measured - -

Exposure 2

Main characteristics
Frequency 1.3 GHz
Charakteristic
Polarization
Exposure duration continuous for 60 min/session, 328 sessions altogather
Modulation
Modulation type pulsed
Pulse width 3 µs
Repetition frequency 370 Hz
Exposure setup
Exposure source
Additional info not closer than 0.57 the far field distance, various distances.
Parameters
Measurand Value Type Method Mass Remarks
power density 570 W/m² mean measured - -
power density 200 W/m² mean measured - to 95 mW/cm²

Exposure 3

Main characteristics
Frequency 5.8 GHz
Charakteristic
Polarization
Exposure duration continuous for 60 min/session; 133 sessions altogather
Modulation
Modulation type pulsed
Pulse width 500 ns
Packets per second 662
Additional info

0.5 or 2 µs pulse width

Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
power density 140 mW/cm² mean measured - -
power density 110 W/m² minimum measured - to 150 mW/cm²

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • during exposure

Main outcome of study (acc. to author)

Observing-response performance was impaired at increasingly higher power densities as frequency increased from the near-resonance 225 MHz to the above-resonance 5.8 GHz.
The threshold power density of disrupted response rate at 225 MHz was 8.1 mW/cm²; at 1.3 GHz it was 57 mW/cm², and at 5.8 GHz it was 140 mW/cm². These power densities were associated with reliable increases in colonic temperatures above sham-irradiated levels. The mean increase was in the range of 1°C, and response-rate changes were not found in the absence of concomitant temperature increases.
In these experiments elevation of colonic temperature was a much better predictor of behavioral disruption than was either the power density of the incident field or estimates of whole-body-averaged rates of energy absorption.

Study character:

Study funded by