Male mice were exposed (n=8) or sham exposed (n=9) in utero during the last gestational week and during the first week after birth. Behavioral tests were performed in the age of 8-11 weeks.
Sociability and the preference for social novelty was tested in the "Three-chambers social apparatus" which is a contruct with three chambers. In a first session, the mouse has the choice to spend time in a chamber with an unknown mouse or without another mouse, while in a second session the mouse can choose between a chamber with the "old mice" from the first session and a "new mouse".
Exploratory behavior was examined using the "Hole-Board", consisting in a wooden board with 16 holes. The number of head-dips into the holes was counted.
|Setup||each of the coils (diameter 40 cm, respectively) had 154 turns, and the coils were separated at a distance of 20 cm; a sinusoidal 50 Hz-current was passed through the magnet; magnetic force lines were parallel to the horizontal component of the local geomagnetic field|
|Sham exposure||A sham exposure was conducted.|
In the "Three-chambers social apparatus", sham exposed mice showed a normal behavior which means that they were significantly more interested in the first session in the unknown mouse than in the empty chamber. In the second session they spent significantly more time in the chamber with the "new mouse" than in the chamber with the "old mouse". In contrast, the exposed mice showed no significant differences in the time they spent in the different chambers in both sessions. Additionally, exposed mice showed a significantly decreased exploratory behavior compared to the sham exposed mice which was shown by a significantly lower number of head dips. No significant differences between the exposure and the sham exposure group were observed regarding anxiety, locomotion, motor coordination and olfactory abilities.
The authors conclude that the results of this study support the hypothesis of a link between exposure to extremely low frequency magnetic fields and autism spectrum disorders, but further research is necessary.