While their body was held in place by a robot arm, the rat would be free to ‘walk’ across the ball. To do so, Tóth built a custom “VR for rats” rig, that placed one of the three rats – Romero, Carmack, or Tom – on a large makeshift trackball in front of a curved monitor that would fill the rat’s field of view. Now, a year later, he’s succeeded in “training rats to kinda play Doom“ (as spotted by PCGamer).

This involved teaching “rats or mice to kill demons and find the exit point by decoding their motor intent and translating it into in-game actions”. In his original experiment, neuroengineer Viktor Tóth writes that he set out to “train rodents to play Doom II with full cerebral control”. READ MORE: Halo, goodbye – how one video game changed my perspective about a whole genre.A neuroscientist has trained lab rats to play a custom version of classic id Software shooter Doom – and named them after three of the original game’s key creators: John Romero, John Carmack, and Tom Hall.

Original doom