It sounds like something out of a science fiction movie: a "biocomputer" powered by human brain cells. In fact, a team of researchers in the journal Frontiers in Science presented a roadmap that could make this scenario a reality in a few decades. In it, the authors outline the development of “organoid intelligence” (OI), which not only makes more powerful and economical computers possible, but could also advance the development of medicines. The basis are brain organoids – tissue structures grown in the laboratory from human cells that are typical for certain brain regions.
Despite all the impressive advances that computer technologies and especially artificial intelligence (AI) have made in recent decades, the human brain is still considered unsurpassed in terms of its learning and memory abilities. However, a new breed of biological computing systems could push the boundaries. So far, the main aim of AI was to make computers more brain-like, but now the brain organoids are to become more computer-like.
Team leader Thomas Hartung from Johns Hopkins University sees three main areas of application for organoid intelligence: It could help to better understand how the brain works. It could also revolutionize the development of drugs to treat neurodegenerative diseases such as dementia. And finally, it could revolutionize computer technology.
According to Hartung, computers can generally process data and numbers faster than humans. But this is still better when it comes to complex logical problems. In addition, a single neuron in the brain can connect to up to 10,000 other nerve cells, which is a completely different way of processing and storing information, according to the scientist.
The team uses illustrations to show what the biological hardware could look like: One of them shows a clump of cells – the organoid – floating in a bowl of liquid and connected to the outside with tiny tubes.
For such organoids, the researchers use cells from human skin samples, which are first transformed into a stem cell-like state and then caused to develop into brain cells. Each of the three-dimensional brain organoids created in this way contains around 50,000 cells, which is still not enough for the intended biocomputer: "In order to support sophisticated calculations, we want to increase this number to ten million," writes the team.
The tube and liquid system shown in the illustration serves the organoids: they receive oxygen, nutrients and growth factors while eliminating waste products. In addition, technologies are described that allow the cells to send information and read out what they "think". The authors plan to adapt tools from different disciplines such as bioengineering and machine learning, as well as to develop new stimulation and recording devices.
Hartung explains: “We developed a brain-computer interface, a kind of EEG cap for organoids, which we presented in a paper published in August. It's a flexible shell densely covered with tiny electrodes that can both pick up signals from and transmit signals to the organoid."
Earlier work has already shown that OI is fundamentally feasible, says Hartung, who specifically cites a study by his co-author Brett Kagan (Cortical Labs in Melbourne). In 2022, his team showed that it is possible to teach brain cell cultures the video game "Pong", in which a point on the screen is hit back and forth in a manner similar to tennis.
According to Hartung, it could still be decades before organoid intelligence can power a system that is as intelligent as a mouse. But there are already complex ethical questions in the room. Could brain organoids feel suffering or even develop consciousness? And what rights do the skin cell donors have? To address these uncertainties, the authors propose that the research process be continuously monitored by a team of ethicists, researchers and members of the public, who jointly identify, discuss and answer relevant questions.
In fact, a statement by the National Academy of Sciences Leopoldina as early as 2022 dealt with the brain organoids, which with the current possibilities could currently reach a maximum of the size of a pea. The Leopoldina authors stated: “The production and research of these new entities can easily evoke unease and concern about exceeding ethically formulated limits of action, since it is about such cell assemblies that form the biological substrate of the human mind and are instrumentalized in a highly artificial way .” In the foreseeable future, however, it is not to be expected that they will be able to develop pain sensations or other, even rudimentary, states of consciousness.
"At the same time, however, brain organoid research is a highly dynamic research field in which substantial progress has been made in recent years and more can be expected in the future," it continues. Then regulations by a special ethics committee could possibly become necessary.
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