The Medtronic Mag Pro, used by an Autralian research neurologist, is used to selectively activate and supress different areas of the brain, to elicit savant-like capabilities, enhanced creativity and mathematical abilities among other things. Really really hard things like instantaneous recognition of large prime numbers. For the non-mathematicians, it’s a very difficult thing to do.
All of this is based on theories about autism and autisitc savants The article explains it well enough. Suffice it to say, maybe you really do only use ten per cent of your brain.
Transcranial Magnetic Stimulation. I’m reminded of the science fiction of Ted Chiang, one of the better speculators about enhanced intelligence. His collection of short stories, Stories of your Life and Others is superb.