Trepanation

Trepanation (from the Greek trypanon, "a borer") is the act of drilling or scraping a hole into the human skull, exposing the dura mater (the outermost of the meninges surrounding the brain). It is one of the oldest forms of medical intervention known today, and has been associated by some, including T. Lobsang Rampa, with increased sensitivity to psychic influences.