correct me if im wrong, but the nervous system uses electrisity to transmit data. your body aslo contains iron - would it not be possible with a strong enough EM feild to simulate the entire nervous system - similar to a taser.

Some researchers do use strong magnetic fields to stimulate very small regions of the brain. This technique, known as Trans-cranial Magnetic Stimulation (TMS), uses a strong, focused magnetic field to activate certain cortical circuits. When the magnetic pulse is applied involuntary movements can be elicited from test subjects (when the magnet is positioned over motor cortex). I have only seen these experiments done with motor cortex but it could be used on any part of the nervous system.

 

Edit:Magnetic pulses elicit neuronal activity by creating currents with all ions present in the nervous system, but potassium and sodium do most of the work for generating action potentials.