According to New Scientist the cells are placed on top of a microelectrode array that analyzes the neural activity... To teach the mini-brains the game, the team created a simplified version of "Pong" with no opponent.
A signal is sent to either the right or left of the array to indicate where the ball is, and the neurons from the brain cells send signals back to move the paddle. OK, it is not to sports game standards but what do you expect from brain matter on a petri-dish?
Brett Kagan, chief scientific officer at Cortical Labs and research lead of the project, said that while the mini-brains can't play the game as well as a human, they do learn faster than some AIs.
"The amazing aspect is how quickly it learns, in five minutes, in real time," he told New Scientist. "That's really an amazing thing that biology can do."
The team at Cortical Labs hope to use their findings to develop sophisticated technology using "live biological neurons integrated with traditional silicon computing."
When the cells are in the game, they actually believe they are the paddle and are just living in the matrix.