24 mice were divided into one exposure group and one sham exposure group (each n=12). The mice were trained to find a submerged escape platform located in a fixed position during four consecutive daily sessions (see Morris water maze). Each session consisted of four trials (with four different starting positions). Each trial had a maximum duration of 60 s and at the end of each trial the animals were allowed to remain on the platform for 20 s. Subsequently, they were returned to their home cage and left there to rest for 15 min before the beginning of the next trial. Exposure or sham exposure was continued during the intervals between the trials.
Modulation type: pulsed
Exposure duration: 1 h 55 min. for the first 3 days (1 h prior to the first trial, 3 x 15 min. between trials, 10 min. after the last trial); 3 hr 45 min. on the fourth days (1 h prior to the first trial, 3 x 15 min. between trials, 2 h prior to the probe trial)
|Exposure duration||1 h 55 min. for the first 3 days (1 h prior to the first trial, 3 x 15 min. between trials, 10 min. after the last trial); 3 hr 45 min. on the fourth days (1 h prior to the first trial, 3 x 15 min. between trials, 2 h prior to the probe trial)|
|electric field strength||23 V/m||minimum||measured||-||inside the cages|
|electric field strength||36 V/m||maximum||measured||-||inside the cages|
|power density||0.05 mW/cm²||minimum||measured||-||inside the cages|
|power density||0.2 mW/cm²||maximum||measured||-||inside the cages|
|SAR||0.41 W/kg||minimum||calculated||whole body||-|
|SAR||0.98 W/kg||maximum||calculated||whole body||-|
The data revealed that during learning sessions, exposed animals showed a deficit in transferring the acquired spatial information across training days (i.e. an increased escape latency was found and an increased distance swam, compared to the sham exposed animals, on the first trial of training days 2-4). Moreover, during the memory probe trial (i.e. absence of the platform) sham exposed animals showed the expected preference for the target quadrant, while the exposed animals showed no preference, indicating that the exposed mice had deficits in memory consolidation and/or retrieval of the learned spatial information.
These data showed that exposure of mice to electromagnetic fields emitted by a mobile phone at SAR values within the ICNIRP guidelines affects the spatial learning and memory function in Balb/c mice.