>'abnormal' brain functions might be similar to artificially induced abnormal brain functions?
Aye, if it weren't for the abnormal states, neuroscientists wouldn't know a fraction of what they've deduced about the normal* functioning of the brain.
I often wonder about how brain pathology would have been perceived back in prehistory. Given that trepanation seems to have originated back in the paleolithic, there must have been an awareness that the mushy stuff inside the skull has a link to behaviour, even if it was just the observation that a whack on the bonce can sometimes make people start to act strangely.
Here's some stuff about holes in the head in times gone by:
http://www.trepan.com/survey.html
*Please take the inverted commas as a given when I'm using the N-word and it's opposite.