Very occasionally I get these strange seizure-like sensations in my brain. I've had them throughout my whole life. The feeling is very difficult to describe; the best I can do is say it's like a quick series of painless electric shocks. It lasts for a second or two and then goes away instantly.
There's a disturbance to my vision as well, equally difficult to describe. Tilt your head to one side and then nod over and over as fast as you can again so that your face is moving in quick little circles. What you'll see is very nearly what I see during one of these episodes.
The attacks can happen any time I am awake, but they seem to be triggered sometimes when I enter a large building with a high ceiling. Cathedrals almost always do it, but I've also experienced it in a huge cave, and in a rainforest.
Any idea what's behind this sensation? Should I be worried?