The Cerebration Mentor, also known as a Cerebraton Mentor, was a device capable of generating emotional impulses.
Its inventor, Professor Watkins, originally devised it as a sophisticated teaching aid. When the Cybermen learned of its existence, they asked their ally, Tobias Vaughn, to destroy it. However Vaughn, eager to use it as a weapon against the Cybermen, kidnapped Watkins and forced him to perfect the device.
Although Vaughn was prevented from mass-producing the Mentor, he ended up using Watkins' prototype against the Cybermen.