In a groundbreaking experiment conducted in Montpellier, scientists connected live slices of human brain cortex to a robotic hand and an electronic piano. After three days of training, the brain tissue was able to replicate piano notes played by humans by controlling the robotic hand, as detailed in a preprint study. The tissue was sourced from donors within 12 hours post-mortem. A slice of the brain, measuring 300 microns in thickness, was cultured on a grid of 60 electrodes, with six electrodes chosen at random—three designated as "motor" and three as "sensory."
During the initial three days, the researchers operated the setup manually. They applied a soft electrical pulse to one of the motor electrodes, prompting the robotic finger linked to that electrode to press a piano key. A microphone captured the sound produced, software identified the corresponding note, and a pulse was relayed to the relevant sensory electrode. At this phase, the tissue did not make any decisions; instead, it was simply required to learn the connection between two sequential events. Feedback regarding correctness was absent, meaning learning relied solely on the timing of the signals.
On the fourth day, the researchers altered the process. A human played a note, the software recognized it, and stimulation was delivered to the related sensory channel. The researchers then evaluated which motor channel exhibited the strongest response, prompting the robot to move the finger linked to that channel. If the brain tissue had grasped the association, the robot would successfully press the corresponding key.
The authors noted an increase in accuracy from 31% to 58.5%, compared to a baseline chance level of 33%. Out of the 16 brain slices, three managed to learn all three associations, while seven learned two out of three. When these slices were tested with untrained electrodes, performance resembled chance levels. Additionally, the use of pharmacological agents to inhibit neurotransmission interrupted the learned behavior. The researchers interpret these findings as evidence of acquired bidirectional plasticity in human brain tissue. The ethical implications of such experiments are a topic of debate, with some advocating for their validity while others express moral concerns.
Informational material. 18+.
