Brain cells on a plate learn to play pong

Scientists have taught a collection of brain cells living on a plate how to play a version of the arcade game pong. The research could one day give doctors a “sandbox” in which to test treatments for brain diseases.

For hundreds of years, the scientific community has attempted to unravel the inner workings of the human brain. This hypercomplex organ contains around 86 billion specialized messenger cells, known as neurons, that control everything from how we mediate our vital bodily functions to how we evoke and express complex thoughts.

Unlocking the secrets of their function would allow scientists to remedy countless ailments and advance a variety of related technologies.

To this end, some of the brightest brainiacs on Earth have created countless computer models of the brain at different scales and levels of complexity. However, an international team of scientists is trying a different approach, taking mouse embryonic brain cells and human brain cells created from stem cells and growing them on an array of microelectrodes.

This array is capable of tracking the behavior of the 800,000 cells and applying electrical stimulation to drive activity in them. In effect, DishBrain, as the team calls it, is a relatively simplistic living model of part of a living brain.

“In the past, models of the brain were developed according to how computer scientists think the brain might work,” says Dr. Brett Kagan, lead author of the new study and chief scientific officer of Cortical Labs. it is based on our current understanding of information technology, such as silicon computing. But in truth, we don’t really understand how the brain works.”

In a new study published in the neuron magazine, scientists took DishBrain and tried to make cells act in an intelligent and coordinated way to complete a task. More specifically, they wanted to see if they could make the myriad cells act as one and successfully play the game of tennis, Stink.

The team used an array of electrodes to create their virtual pong court. They were able to tell the cells which side of the court the ball was on using electrical signals, and the frequency of these signals was used to indicate their direction and how far the ball was from passing through an invisible wall to score.

According to a press release from the Australian site Science in Public, feedback from the electrodes was also used to teach the model brain how to return the ball. More specifically, the activity of cells in two defined regions of the dish was collected and used to move a virtual paddle up and down.

However, training the model’s brain to correctly move the paddle was a challenge. Normally, the brain releases dopamine to reward correct action, and this, in turn, encourages the subject to act in a specific way. With DishBrain, this was not an option.

Instead, the team turned to a scientific theory known as the “free energy principle,” which states that cells, like neurons, will go to great lengths to reduce the unpredictability of their environment.

The team implemented the theory by hitting home plate with an unpredictable electrical stimulus when the paddle failed to intercept the ball, after which the virtual ball would activate again in a random vector. In contrast, if the neurons were able to move the paddle to successfully deflect the ball, a predictable electrical stimulus was applied to all the cells at once, after which the game continued in a predictable fashion.

Since the cells were inclined to make their environment predictable, they worked to understand the game and prolong the pong rally.

“The beautiful and pioneering aspect of this work lies in equipping neurons with sensations, feedback, and, crucially, the ability to act on their world,” says Professor Karl Friston, co-author of the new University College study. London. “Surprisingly, cultures have learned how to make their world more predictable by acting on it.”

The team found that DishBrain’s ability to extend a rally improved significantly over the course of just five minutes. In other words, the cells were able to self-organize to complete a goal, using what the researchers defined as synthetic biological intelligence.

“The translational potential of this work is really exciting: it means we don’t have to worry about creating ‘digital twins’ to test therapeutic interventions,” says Professor Friston. “We now have, in principle, the ultimate biomimetic ‘sandbox’ in which to test the effects of drugs and genetic variants: a sandbox made up of exactly the same computing (neuronal) elements found in your brain and in mine”.

In the future, the researchers plan to give DishBrain alcohol to see how it affects his pong performance. One day, the study authors hope the model could provide a useful alternative to animal testing and enable clinicians to gain new insights into degenerative diseases such as dementia.

Anthony Wood is a freelance science writer for IGN.

Image Credit: Cortical Labs

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