|MadSci Network: Biophysics|
According to electromagnetic theory any current flowing through a conductor will produce a magnetic field. This is true in the human body of the electrical signals that are conducted through neurons and muscles. These magnetic fields can be measured using devices called magnetometers. Most of these use superconducting sensors cooled by liquid helium to measure the very small magnetic fields produced by the brain. By measuring these fields it is possible to determine the areas of the brain with migh electrical activity during various activities.
To my knowledge it is not possible to 'demagnetize' the body, but strong magnetic field pulses can be used to induce currents in muscles and neurons. One device called a transcranial nerve stimulator (or transcranial magnetic stimulator) can cause a person to move their arm or even put them into a seizure.
Hope it helps.
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