Photo: National Institute of Allergy and Infectious Diseases, NIH
Lab-grown brain organoids managed to balance an unstable vertical pole, demonstrating how living neural circuits can be guided to solve classic control problems through structured feedback, according to ScienceAlert.
Researchers cultivated clusters of mouse stem cells into small pieces of cortical tissue capable of transmitting neural signals. Placed in a closed system that delivered electrical feedback based on performance, the organoids steadily improved their ability to control a classic engineering benchmark: stabilizing a virtual inverted pole. Although they were far from functioning like biological computers, the results showed that neural tissue in a Petri dish can be tuned through feedback signals.
“We’re trying to understand the fundamental principles that allow neurons to be adaptively configured to solve problems,” said Ash Robbins of University of California, Santa Cruz. He noted that uncovering these mechanisms could open new ways to study how neurological disorders affect brain plasticity and learning.
The task used in the experiment—the “cart-and-pole” problem—is conceptually simple but mathematically unstable. A virtual cart must move left or right to keep a hinged pole balanced upright. Small errors quickly accumulate, making it a standard test in reinforcement-learning research because it demands continuous fine-tuning rather than a single correct response.
In the setup, electrical stimulation patterns signaled the pole’s tilt direction and angle. The organoids’ neural responses were interpreted as control signals that pushed the cart accordingly. Importantly, the tissue did not “understand” the task; scientists were testing whether neural connections could be shaped through feedback to improve performance.
Related work at Northwestern University previously showed that lab-grown spinal cord organoids could recover function after experimental injury, highlighting the potential of such systems for studying treatments for paralysis and other neurological conditions.
