Researchers grew human brain tissue – and discovered it is capable of 'learning'

Scientists at the University of Tokyo grew tiny clumps of human brain tissue from stem cells, connected them to a chip network, and demonstrated that the tissue can learn to recognize different electrical signals. The experiment, published in Communications Biology, shows how networks of three connected clumps rewire themselves and divide roles, similar to the human brain.

A team of researchers at the University of Tokyo, led by brain researcher Yoshiho Ikeuchi, succeeded in growing tiny clumps of human brain tissue from stem cells in a lab dish, connecting them to an active chip network, and proving that the tissue can learn to distinguish between different electrical signals. The experiment was published in the journal Communications Biology. The researchers placed the tissue clumps on chips coated with tiny electrodes. Networks that included three connected clumps showed a dramatic change: the third clump, which did not receive direct currents, developed faster and more accurate responses and was able to identify where the electrical signal came from. In contrast, chips with one or two clumps showed no improvement. The study demonstrates that in order to learn and perform basic information processing tasks, brain cells must be organized into modular networks that divide roles among themselves. The researchers emphasize that the electrical pulses rewired the nerve cells and led them to specialize in different roles, similar to the human brain. The tissues are far from having consciousness, but this is the first experimental proof of its kind. The study of brain organoids is considered a growing field in modern biology, also used to examine neurological diseases such as Alzheimer's, Parkinson's, and epilepsy, and to test personalized drugs.