An electro-prober was a device used aboard Federation starships in the 23rd century to measure and record an officer's brain patterns and transmit them into a cerebot's memory banks. The process incapacitated the officer for at least several hours, during which time the body needed to be kept in a life support cabinet, and resulted in him having a terrible headache for several days.
History and specifics[]
In the year 2266, Montgomery Scott used an electro-prober to copy the brain patterns of Leonard McCoy and Spock into cerebots. (TOS comic: "The Trial of Captain Kirk")