Scientists taught lab-grown human brain cells to play ‘Pong’
Researchers who have grown a culture of brain cells in the lab say they have taught the cells to play a version of Pong. Scientists at biotech startup Cortical Labs say this is the first demonstrated example of how a so-called “mini-brain” has been trained to perform purposeful tasks. “It is able to take in information from an external source, process it and then respond to it in real time,” said to BBC Dr Brett Kagan, lead author of the research article, published in the Neuron journal.
The culture of 800,000 brain cells is known as DishBrain. The scientists placed mouse cells (derived from embryonic brains) and human cells derived from stem cells into an electrode array that was connected to Pong, as The Age reports. Electrical impulses transmitted to 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 (actually a form of stimulus) when the paddle hit the ball, and a short, random pulse when it missed.
The researchers, who consider the culture 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 became better at the game. The scientists say this shows that 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.”
DishBrain’s future research will include studying how drugs and alcohol affect the culture’s ability to play pong, to see if it can be effectively used as a substitute for the human brain. Kagan expressed hope that DishBrain (or perhaps future versions of it) could be used to test treatments for diseases such as Alzheimer’s.
Meanwhile, researchers at Stanford University grew stem cells from human brain tissue, which were then transplanted into newborn rats. These so-called brain organoids were integrated with the rodent’s own brain. A few months later, the scientists discovered that the organoids make up about a third of the rat brain hemispheres and that they interact with rodent brain circuits.
As Wired points out, these organoids could be used to study neurodegenerative disorders or to test drugs designed to treat neuropsychiatric diseases. Scientists can also investigate how genetic defects in organoids can affect animal behavior.