Likely they are causing the pituitary gland to enlarge and then removing it.
A quote from the book:
Transhumanism: The History of a Dangerous Idea
https://www.goodreads.com/book/show/26270060-transhumanism
Thelema is the religion started by Aleister Crowley.
The Cabal is run by a Thelemic order of the Lamp of Invisible Light or LIL.