If you were around in the 80s you might remember one of the first video games, called Pong. While it looks ridiculously simple and boring to a player of today's video games, Pong made a huge splash when it came out, and teenagers and kids were just as excited about playing it as today's players might be with a current release. The game consists of a paddle (or two in the two-player version) that moves up and down the screen, and a ball that stays in motion, bouncing around the screen. As the ball approaches the side with the paddle, the paddle has to hit the ball, like in a ping-pong match, and if it doesn't, the game ends.
So how little skill is required to play this very basic game? Very little, it seems. Scientists have now taught a mass of brain stem cells growing on a microelectric array in a dish to play the game. The pre-print study has been reported on bioRxiv.
The human stem cells on the array can detect activity in the cells around them, and stimulate one another. The array provides a source of electricity, which is used by neurons in the human body to propagate signals. The electrical signals sent to the array can 'tell' the neurons where the ball is; if the cells are stimulated by electrodes to their right, this tells the cells that the ball is to the left. The signal's position can be modified to provide information about frequency too.
This system was termed a cyborg by the researchers, who taught the cyborg to play the game by moving the paddle into the ball's path by sending electrical signals through the electrodes. The cells learned to play in only about five minutes, which is quicker than artificial intelligence (AI) machines. However, the researchers noted that the cyborg was not as good at playing the game as humans or AI.
This work could help improve machine learning or therapeutics for the brain, the researchers suggested.