Scientists got lab-grown human brain cells to play ‘Pong’

Researchers who grew a brain cell culture in a lab claim that they taught the cells to play a version of Pong. Scientists from a biotech startup called Cortical Labs say it’s the first demonstrated example of a so-called “mini-brain” being taught to carry out goal-directed tasks. ”It is able to take in information from an external source, process it and then respond to it in real time,” Dr. Brett Kagan, lead author of a paper on the research that was published in Neuron, told the BBC.

The culture of 800,000 brain cells is known as DishBrain. The scientists placed mouse cells (derived from embryonic brains) and human cells taken from stem cells on top of an electrode array that was hooked up to Pong, as The Age notes. Electrical pulses sent to the neurons indicated the position of the ball in the game. The array then moved the paddle up and down based on signals from the neurons. DishBrain received a strong and consistent feedback signal (effectively a form of stimulus) when the paddle hit the ball and a short, random pulse when it missed.

The researchers, who believe the culture is too primitive to be conscious, noted that DishBrain showed signs of “apparent learning within five minutes of real-time gameplay not observed in control conditions.” After playing Pong for 20 minutes, the culture got better at the game. The scientists say that indicates the cells were reorganizing, developing networks and learning.

“They changed their activity in a way that is very consistent with them actually behaving as a dynamic system,” Kagan said. “For example, the neurons’ ability to change and adapt their activity as a result of experience increases over time, consistent with what we see with the cells’ learning rate.”

Future research into DishBrain will involve looking at how medicines and alcohol affect the culture’s ability to play Pong, to test whether it can effectively be treated as a stand-in for a human brain. Kagan expressed hope that DishBrain (or perhaps future versions of it) can be used to test treatments for diseases like Alzheimer’s.

Meanwhile, researchers at Stanford University cultivated stem cells into human brain tissue, which they transplanted into newborn rats. These so-called brain organoids integrated with the rodents’ own brains. After a few months, the scientists found that the organoids accounted for around a third of the rats’ brain hemispheres and that they were engaging with the rodents’ brain circuits. As Wired notes, these organoids could be used to study neurodegenerative disorders or to test drugs designed to treat neuropsychiatric diseases. Scientists may also look at how genetic defects in organoids can affect animal behavior.