Mind probe

A mind probe was a device which allowed an operator to extract information from a subject's mind through the use of some kind of projected energy. Although many civilisations used mind probes, they were dangerous to the subject, and sometimes unreliable.

Nature
Subjects were said to be at risk of brain damage if they were exposed to these devices for either long periods or high power outputs. (PROSE: Engines of War) Jack Harkness once claimed that mind probes had "a 100% success rate, counting only the survivors". (PROSE: The Undertaker's Gift)

The Third Doctor once told Jo Grant that he had found a way to defeat mind probes, and quipped that he'd once destroyed a government's entire supply of probes. His method was to tell the truth in obscure wording to make it seem like he was talking gibberish. (TV: Frontier in Space)

Gallifreyan mind probes
A mind probe of Gallifreyan design was going to be used on the Castellan to discover the truth about the Black Scrolls of Rassilon, but he was shot before they could use it on him. Nevertheless, he exhibited great fear of the mind probe, hinting at its power against the Time Lord brain. (TV: The Five Doctors)

The Eleven used a mind probe on Coordinator Farina in order to extract the access codes he needed to enter the Omega Vault. In doing so, he "burned out" her mind. (AUDIO: The Eleven)

War Interrogator Dionus took an "interrogation device" with him when he left the Homeworld's service, bringing it to Gulliver's Rest where he found refuge. He brought it out of storage to use it on an unconscious "Nari", on a low setting. This allowed him to realise that her "Nari" persona was not just an act as he had believed, but a fully-fledged alternative personality that the Homeworlder had constructed for herself to evade deduction. (AUDIO: Me & My Ghost)

During the Last Great Time War, two members of the High Council of the Time Lords on Gallifrey, Karlax and the Castellan, administered the probe to Cinder. Although human, she managed to survive it. (PROSE: Engines of War)

Human mind probes
Torchwood Three had access to a mind probe. They used it on Beth Halloran when they were trying to discover whether she had attacked the burglars who broke into her house. Ianto remarked that the last alien they used it on had exploded. (TV: Sleeper)

General Nikolai Hermack considered using a mind probe on Milo Clancey to see if Clancey was telling the truth about being robbed by space pirates. (TV: The Space Pirates)

Earth Security also employed mind probes around the time of the Daleks' attempt to stir up hostilities between the Earth Empire and the Draconian Empire. The Third Doctor as subjected to it while believed to be a Draconian spy. (TV: Frontier in Space)

Dalek mind probes
Dalek X used a mind probe to torture and interrogate the Tenth Doctor. (PROSE: Prisoner of the Daleks)-

The Daleks used mind probes to extract the blue prints for the persuasion machine. (AUDIO: Daleks Among Us)

Other mind probes
The Third Doctor used his technique to blewour Draconian and mind probes as well as the Earth Security's. (TV: Frontier in Space)