Effects of MR exposure on cell proliferation and migration of chick motoneurons.

The effect of magnetic resonance (MR) exposure on the proliferation and migration of motoneurons was examined in chick embryos. Embryos were exposed in ovo to a static magnetic field of 1.5 T for 6 hours and to 64-MHz radio-frequency field pulses and a switched magnetic field gradient with an amplitude of 0.6 G/cm for 4 hours. For cell proliferation studies, embryos were exposed to MR fields during the developmental stage at which motoneuron proliferation is most active. For cell migration studies, embryos were exposed to MR fields at the developmental stage just before lateral motoneuron migration. The results show that the birth dates, migration, and proliferation of lateral motoneurons were unaffected by the MR exposure conditions in this study.