Locomotor Responses of Utricular Mutants to High Magnetic Field Exposure

Wild-type mice or head-tilt (het) or tilted (tlt) mutant mice were exposed to static 14.1 T magnetic field, or sham-exposed, for 30 min; locomotor activity was recorded for 2 minutes after exposure. The het and tlt mice lack otoconia in the inner ear, and are unresponsive to vestibular linear acceleration. After magnetic field exposure, wild-type mice and tlt mice show suppressed rearing and tight counter-clockwise circling. The het mutant mice do not show circling nor is their rearing suppressed. This suggests that otoconia, or a function that depends on otoconia, are required for full vestibular responsiveness to magnetic fields