Our brain is an ace and is capable of performing 15 quintillion operations per second thanks to our trillion neuronal connections.
Technology has transformed societies mainly because machines are now capable of performing increasingly complex activities like humans. However, they are still far from reaching the capabilities of the human brain, for machines alone to retain the same amount as our minds would require 34 coal-fired plants generating 500 megawatts per hour. Our brain is an ace and is capable of performing 15 quintillion operations per second thanks to our trillion neuronal connections. But scientists are still trying to emulate brain functions and have now created microchips from human cells capable of playing pong.
Study of the brain on a plate
Cortical Labs, a laboratory that calls itself the pioneer in biological computing, has recently published its first achievement in the journal Neuron, where it claims that its living chips are capable of playing pong, a video game inspired by table tennis. With this, they have demonstrated that hybridization between biology and mechanics is entirely possible.
The system, named “DishBrain”, contains two types of cells: the first would be live neurons that have been harvested from mouse embryos, and the other part would be human induced pluripotent stem cells. The latter are stem cells created from human tissues such as skin that can be reverted to a stem state and later reconverted into other cells, in this case, neurons.
The team, led by Brett Kagan, took advantage of the fact that both circuits share electricity as a common language; in computers with silicon chips, electrical signals travel through metal wires that connect the different components. In the brain, neurons communicate through synapses, junctions between nerve cells, using electrical signals. In this system, when neurons grow on the chips, they act as wires connecting the various components.
Cells playing pong
The study continued with the programming of the cells so that they would be able to perform a specific task, in this case playing the classic video game Pong where the player must hit a ball to avoid it touching the bottom. To do this, they placed plates with microelectrodes on which the cells were grown to read their activity and stimulate them.
Electrodes on both sides of the array were activated to tell DishBrain which side the ball was on, while the frequency of the signals indicated the distance of the racket. Feedback from the electrodes taught the system how to return the ball, so the cells began to act as if they were the racquet.
“We’ve never been able to see how cells act in a virtual environment before,” Kagan explained. “We were able to build a closed-loop environment that can read what’s going on in the cells, stimulate them with meaningful information, and then interactively change the cells so they can actually alter each other.”
The system supports the free-energy principle, where Karl Friston describes the basic workings of the brain. Dishbrain did not behave as silicon-based systems do, the team observed the chips learn to play in as little as five minutes after they began to be stimulated because the human brain cell systems learned to play faster than those created with mouse embryonic cells.
At the same time, there is also the question of how much these devices can feel. “As recently discussed, there is no evidence that neurons in a dish have a qualitative or conscious experience, so they cannot be distressed and, without pain receptors, they cannot feel pain,” Kagan explained.
Today, neurons have evolved to be able to process all kinds of information. So, all this study does is allow neurons to behave as their nature intended. According to the authors, the future of this work lies in disease modeling, drug discovery, and expanding the understanding of brain function. According to Hoy Weng Chong, the director of Cortical Labs.
[Photos: Cortical Labs]
Story originally published in Spanish in EcoosferaPodría interesarte