Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale
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Many studies show consistently that repetitive transcranial magnetic stimulation (rTMS) with a frequency of 1 Hz and an intensity above the resting motor threshold (RMT) performed for several minutes over the primary motor cortex (M1) leads to a depression of cortical excitability. Furthermore, most studies concur on a facilitation of the non-stimulated contralateral M1. Little is known, however, about the physiological mechanisms underlying these effects. ⋯ In conclusion, the MEP increase in the non-stimulated M1 lasted longer than the MEP decrease in the stimulated M1. Only the long-lasting MEP increase was associated with a specific change in intracortical excitability (increase in SICF). Modulation of motor cortical inhibition did not play a role in explaining the rTMS induced changes in MEP amplitude.