Behavioral effects of static high magnetic fields on unrestrained and restrained mice.

High-strength static magnetic fields are common tools in clinical imaging, but the behavioral effects are not well characterized. Previous studies on rats showed that fields of 7 T or above produced locomotor circling, conditioned taste aversion (CTA) and c-Fos in vestibular nuclei. To determine the generality of the behavioral effects on a smaller species, we subjected restrained or unrestrained mice to 30-min exposures in a 14.1-T field. Mice were given saccharin immediately prior to magnet or sham exposure on 3 consecutive days. All mice exposed to the magnet developed a CTA, and a significant number displayed tight circling and suppression of rearing. Unrestrained mice exhibited larger effects than restrained mice. These effects, similar to the effects in rats, may be the result of a vestibular disturbance caused by the magnetic field.