High Quality Content by WIKIPEDIA articles! "Spock`s Brain" is the first episode of the third season of Star Trek: The Original Series, first broadcast September 20, 1968. It was the first episode to air after NBC moved the show from 8:30 P.M. to 10 P.M. on Friday nights. It was repeated July 8, 1969. It is episode #56, production #61, written by Gene L. Coon (under the pseudonym Lee Cronin) and directed by Marc Daniels.