Physicists have taught a collection of living brain cells to play an arcade version of 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 uncover the inner workings of the human brain. This hypercomplex organ contains about 86 billion specialized message cells, called neurons, which control everything from how we mediate our vital bodily functions, to how we plan and express complex thought.
Unlocking the secrets to their role allows educated people to cure countless ailments, and to advance a range of related technologies.
To this end, some of the most famous brains on Earth have created countless computer models of brains at various scales and levels of complexity. However, an international team of scientists seeks a different approach by taking embryonic mouse brain cells and human brain cells created from stem cells and growing them on top of microelectrodes.
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This system can track the behavior of 800,000 cells and apply electrical stimulation to prompt action in them. In fact, DishBrain, as the team calls it, is a relatively simplistic living model of a living part of the brain.
“In the past, models of the brain have been developed based on how computational scientists think the brain might work,” comments Dr. Brett Kagan, author of the new study and chief scientific officer at Cortical Labs. “That’s mostly based on our understanding of information technology, like the computing chip. But we don’t really understand how the brain works.
In a new study published in the journal Neuron, scientists took DishBrain and tried to make the cells actually intelligent, organized in a way to complete the task. More specifically, they wanted to see if the myriad cells could play one, and successfully played the game of tennis, Pong.
The team used a series of electrodes to create a virtual pong court. They could tell the cells from the other side of the ball using electrical signals, and the frequency of these signals was used to indicate its direction, and how far the ball would pass from the invisible wall to score.
According to a press release from the Australian Science in Public website, the feedback from the electrodes was also used to teach the brain model how to return the ball. More specifically, the activity of cells in two defined regions of the dish was collected and used to move the pin up and down to the right.
But the training of the brain model to move the oar correctly was challenging. Normally, dopamine is released by the brain to reward the correct action, and this in turn challenges the subject to a specific action. With DishBrain, it didn’t go well.
Instead, the team turned to a scientific theory called the “free energy principle,” which posits that cells like neurons will do what they can to reduce fluctuations in their environment.
The team implemented the theory by hitting the disc with a stray electrical impulse when the pin failed to intercept the ball, after which the virtual ball went off again in a random direction. Conversely, if the neurons were able to successfully deflect the stick to the ball, a predictive electrical stimulus was applied to all cells at once, after which the game continued in the predictive manner.
As the cells trained to predict their environment, they worked to understand the game and prolong the pong match.
“The beautiful and powerful system of this work is based on the neurons of the senses – the ability to respond and fix the action in the world,” says Professor Karl Friston, co-author of the new study from University College London. “Cultures have learned in a strange way how to make their world predictable by acting on it.”
The team found that DishBrain’s ability to increase capacity significantly increased over the course of just five minutes. In other words, cells would be able to self-organize to achieve a goal, using what researchers have 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,” comments Professor Friston. Now we have at the beginning the “ultimate biomimetic sandbox” in which to test the effects of drugs and genetic variants – a sandbox from the same computing elements (neuronal) found in the brain and mine.
The development researchers plan to give DishBrain alcohol to see how it affects its performance in pong. One day, the authors of the study hope that the model can provide a useful alternative to animal testing, and allow doctors to gain new insights into degenerative diseases like dementia.
Anthony Wood is a science writer for IGN
Image credit: Cortical Labs
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