The new trial for adjustment of cortical excitability induced by static magnetic stimulation

Abstract

The aim of the present study was to investigate in healthy volunteers the neurophysiological mechanism of motor cortical excitability by the application of static magnetic fields stimulation exposure. This stimulation was obtained using cylindrical NdFeB magnets. Transmagnetic stimulation (TMS) to test the changes of cortical excitability was measured in 9 healthy volunteers. The static magnetic stimulation was applied over the primary motor cortex for 20 minutes as an intervention, and TMS measurements were performed before, 0 min, 10 min, 20 min and 30 min after the intervention. We observed an average reduction of motor cortex excitability of up to 20% immediately after the intervention, as revealed by TMS. The rest motor threshold was also significantly increased. Moreover, it showed the increase of short intracortical inhibitory, which is mediated by Gamma Amino Butyric Acid (GABA) receptors. These results revealed that cortical excitability changes have origin at the cortical level, and suggested that these changes by static magnetic stimulation might be due to enhancement of the inhibitory systems via GABA system as well as the increase of the membrane excitability threshold.