The Neuro-Overrider is an object that appears in the Sonic the Hedgehog comic series and its spin-offs published by Archie Comics. It was a small computer-chip-like device invented by Rotor Walrus. It lets the user retain free will after Roboticization.
The device was first meant to be used in a sabotage attempt on Robotropolis that involved roboticizing Princess Sally Acorn. Unfortunately, it fell off her in during roboticization. It was discovered by Snively and destroyed by Robotnik. Sally was under the dictator's control until she and the Freedom Fighters were rescued by Dulcy the Dragon.
Sonic the Hedgehog later proposed a plan to let himself become a Robian while wearing one of the devices in order to destroy Robotropolis with an enhanced body, but it was rejected by Princess Sally on account of being too risky. Sonic was then Roboticized against his will, but even if approved, his plan would not have worked anyway. After Snively analyzed Sally's Neuro-Overrider and deduced its function, Robotnik upgraded all his Roboticizers with Brain-Burn-Thru software which assured complete control over all Robians, particularly Mecha Sonic.
In order to combat Mecha Sonic when he attacked Knothole Village, Knuckles became Mecha Knuckles using a Neuro-Overrider and an old Roboticizer that did not have the Brain-Burn-Thru software so that he would not turn on the Knothole Freedom Fighters.