When transcranial magnetic stimulation (TMS) is applied to certain areas of the brain, once can induce movement of a body part or interfere with speech. This is because the generated electric field influences neurons. The use of TMS at the sensorimotor cortex is quite harmless, but what are the dangers when it is applied to the brain stem? That brain region controls vital functions, such as heart rate and breathing. Could TMS be dangerous when improperly applied?