A team of researchers at the Cortical Laboratories in Melbourne conducted experiments with human and mouse cells and found that the nerve cells in the test dishes could learn to play the game, Pong.
“Organs-on-chips” is one of the systems used in recent years to understand organ functioning better. Brains-on-chips are a type of system in which cells in test dishes interact with chips that mimic the functioning of organs. The latest study by Dr. Brett Kagan and colleagues is an example of brain-on-a-chip research.
Human and mouse nerve cells were used in the experiments. The cells are stimulated by a chip consisting of a network of electrodes, and their responses are detected and recorded by the same chip.
There are over 80 billion neurons in the human brain and around 70 million in the mouse brain. The systems in the experiments have about 800,000 neurons. This is almost as many neurons as there are in a wasp’s brain.
The chip, designed to simulate the game of Pong, stimulates nerve cells by applying voltage. The chip fires electrodes on the right or left side to tell the cells whether the ball is on the right or left side. The distance to the ball is expressed by varying the frequency of the applied voltages. The chip moves the virtual palette according to how the nerve cells respond to these impulses. If the ball is not reflected off the track, the cells are exposed to high voltages generated by electrodes at random points. The experiments show that the cells’ responses to the signals from the chip evolve over time and that the cells gradually learn to play the game.
Researchers say that the development of nerve cells’ responses to stimuli over time is not an indication of consciousness and that the observed process can be likened more to reflexes.