In Which Our Intrepid Hero has Transcranial Magnetic Stimulation

Once again, I have put my body to the test. Opened myself to prods and insistent questions. Sacrificed so that the sum of knowledge could grow. Yes, that's right, I was a paid subject for a human experiment.

This experiment was not terribly unpleasant. It was all a matter of sitting still while the experimenter discharged big capacitor banks through (insulated) wire coils he pressed up against the back of my head. No biggie. Turns out that when you discharge the capacitors, a great big current pulse flows through the coils. When that happens, there's a big pulse of magnetic field along (most particularly) the axis of coils. Further, magnetic pulse tends to interact with your brain in interesting ways.

A great deal of literature indicates that this practice is quite safe; people've been doing these experiments for at least 15 years and there's no indication that it has any malinfluence on the subjects.

Anyway, the magnetic field can stimulate the brain in nifty ways. In this case, he aligned the coils so the magnetic field would interact with the primary visual cortex. As a result, when the caps (capacitors) were discharged, the pulse of magnetic field would make me see this crazy spot just right of the center of my field of vision.

Apparently the idea is to flash some picture up on a screen and then, an instant later, stimulate the cortex and determine how the picture persists in the brain. Pretty swell stuff. I'm going to do it again next week for an hour; we'll see if there are more cool stories of bizarre field-induced hallucinations.