Here’s interesting passage about magnets interacting with the brain from the National Geographic Brain book.

The brain creates its own tiny magnetic fields. A new, noninvasive process called transcranial magnetic stimulation, or TMS, subtly alters the brain’s magnetic processes without resorting to drugs or surgery.
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When applied to the prefrontal lobes, TMS has been shown to enhance the speed and agility of cognitive processing.

In the past, I’ve commented to friends that my generation is probably the last generation right before the era in which technology and bioengineering enable humans to live vastly longer and more powerful lives. I’ll be 85, in some hospital room hooked up to dialysis, and the nurse will come in and say, “Boy, if you’d only been born 20 years later we could have used nanobots and magnetic therapy to clean up your blocked arteries and enhance your mental function as well as making you look 50 years younger. As it is, you’re just a dejected, degenerate old man with a flaccid penis that everyone laughs about back at the nursing station.”