Transcranial magnetic stimulation alters the activity of the brain without the need for an invasive physical procedure. But for such a ground-breaking and potentially alarming technique, it is not very well known.
If you were to tell people that the technology exists to manipulate the workings of people's brains, they may not believe you. That sort of thing is the stuff of cheap sci-fi B movies. If someone in the real world were to try to develop it, that's exactly the sort of scenario where they'd send James Bond in to stop them before it got too far.
But the fact is that this technology genuinely exists and is widely used in neuroscientific research. It is known as Transcranial magnetic stimulation, or TMS, and as the name suggests it stimulates the brain through the cranium using magnetism.
Magnets and the brain work together a lot. Neuroscience is an increasingly media-friendly area of science, and this is due in part to the increasing use of magnetic resonance imaging (MRI), an invaluable but complex technique that uses intense magnetic fields and radio waves to produce eye-catching images of a working body and brain.