Transcranial magnetic stimulation (TMS) is a technique whereby magnetic fields are used to temporarily alter the function of the brain by inducing an electrical current in the brain tissue.
In neuroscience research, TMS usually refers to the use of powerful magnetic fields (about 1.5 tesla or 40,000 times the earth’s magnetic field) focused on approximately 1x1cm areas of the cortex.
Repetitive TMS (rTMS) can be used either to make the area more active or less active over a specific time period (often 30 minutes or so), while single pulse TMS is used to harmlessly ‘knock out’ an area for approximately 100ms.
Much weaker magnetic fields (about the strength of a loudspeaker) but much more complex in form, have also been used to induce unusual experiences by stimulating the temporal lobes, most notably by neuroscientist Dr Michael Persinger.
A new project called Open-rTMS aims to develop this latter type of system (actually, generally not referred to as TMS in the neuroscience literature) and publish the plans and software online.
They’re currently looking for people to sign up to the mailing list and kick the project off, so if you’re looking for a way to alter your state of consciousness with magnets, this might be your chance.