Magnetoreception in laboratory mice: sensitivity to extremely low-frequency fields exceeds 33 nT at 30 Hz

Area of Science:

• Neuroscience
• Biophysics
• Animal Behavior

Background:

• Magnetoreception research typically focuses on static geomagnetic fields for animal navigation.
• The impact of weak extremely low-frequency magnetic fields (wELFMF) on animal behavior is understudied.
• Nociception (pain perception) changes in shielded environments offer a potential biological endpoint for magnetoreception studies.

Purpose of the Study:

• To investigate the effects of weak extremely low-frequency magnetic fields (wELFMF) on nociception in mice.
• To determine if a 30 Hz magnetic field, significantly weaker than the Earth's static field, alters pain perception.

Main Methods:

• Mice were housed in an ambient magnetic field-shielded environment for 1 hour daily over five days.
• Nociception was assessed, with and without the introduction of static or 30 Hz time-varying magnetic fields.
• A 30 Hz field of 33 nT and a static field of 44 µT were applied.

Main Results:

• Five days of exposure to a shielded environment induced a significant analgesic effect in mice.
• A static magnetic field (44 µT) had minimal impact on this analgesic response.
• A weak 30 Hz time-varying magnetic field (33 nT) significantly reduced the analgesic effect by 60%.

Conclusions:

• Mice exhibit high sensitivity to weak, 30 Hz time-varying magnetic fields, affecting nociception.
• These findings suggest that magnetoreception mechanisms must account for responses to wELFMF.
• Nociception is a viable endpoint for studying magnetoreception, particularly concerning weak magnetic field effects.