Medical/biological Study (experimental study)

Temporal patterns of extremely low frequency magnetic field-induced motor behavior changes in Mongolian gerbils of different age. med./biol.

PubMed Entry

Journal web site

Aim of study (according to author)
To study the effects of a seven-day exposure to an extremely low frequency magnetic field on different behaviour parameters in gerbils of different age. The behaviour parameters were investigated on the 1^st, 2^nd, 4^th, and 7^th day of exposure (immediate effect) and three days after exposure has been ceased (delayed effect).
Background/further details:
The following main groups were investigated: three-month-old male gerbils (n = 35) and ten-month-old male gerbils (n = 35).
The animals were divided into two control groups (cage control and sham exposed) and three exposure groups (0.1, 0.25 and 0.5 mT).

Endpoint

• cognitive/behavioral endpoints: locomotor activity, stereotypy, and immobility

Exposure
General category: magnetic field, low frequency field, 50/60 Hz (AC)

Field characteristics	Parameters
50 Hz exposure duration: continuous for 7 days	magnetic flux density: 8.9 mT max value (on the electromagnetic poles) magnetic flux density: 0.5 mT mean value (at a distance of 20 cm) magnetic flux density: 0.25 mT mean value (at a distance of 28 cm) magnetic flux density: 0.1 mT mean value (at a distance of 40 cm)

Exposed system:
animal (species/strain): Mongolian gerbils (Meriones unguiculatus)

Methods
Endpoint/Measurement parameters/Methodology

• cognitive/behavioral endpoints: locomotor activity, stereotypy, and immobility: open field test

Main outcome of study (according to author)
Exposure to an extremely low frequency magnetic field for seven days (0.1, 0.25 and 0.5 mT) stimulated motor behaviour (locomotor activity and stereotypy) in 3-month-old gerbils, whereby the most significant changes were observed after the first day of exposure. Simultaneously, a significant reduction of immobility during the entire period of the seven-day exposure was reported. Additionally, exposure to the different extremely low frequency magnetic fields had a delayed effect (except 0.25 mT) on stereotypy (decrease) and immobility (increase).
The effect of the extremely low frequency magnetic fields on the behaviour of ten-month-old gerbils largely depended on the value of the electromagnetic induction. On the first exposure day an extremely low frequency magnetic field of 0.1mT decreased, 0.25 mT had no effect and 0.5 mT increased motor behaviour (locomotor activity and stereotypy). But a significant increase of motor behaviour after the second day of exposure with 0.25 mT was reported. Furthermore, a significant reduction of immobility during the entire period of the seven-day exposure to 0.5 mT was noticed.
Three days after exposure has been ceased (delayed effect), significant stimulation of motor behaviour and reduction of immobility time was observed in all exposed groups compared to the control group.
In conclusion, the results revealed the specific temporal patterns of immediate and delayed motor behaviour changes in three- and ten-month-old gerbils induced by extremely low frequency magnetic fields, which could be due to age-dependent differences in the brain structures (responsible for a control of motor behaviour).

(Study character: medical/biological study, experimental study, full/main study)

Study funded by

• Military Medical Academy (MMA), Serbia
• Ministry of Education and Science, Serbia

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