Dr. Thomas Hartung with brain organoids in his lab at the Johns Hopkins Bloomberg School of Public Health in Baltimore.
(Courtesy: Will Kirk/Johns Hopkins University)
(CNN) --
Computers powered by human brain cells may sound like science fiction, but a team of US researchers believe that these machines, part of a new field called "organoid intelligence," could shape the future, and now they have a plan to achieve it.
Organoids are laboratory-grown tissues that resemble organs.
These three-dimensional structures, usually derived from stem cells, have been in use in laboratories for nearly two decades, where scientists have been able to avoid harmful tests on humans or animals by experimenting with substitutes for kidneys, lungs and other organs.
Brain organoids don't actually resemble tiny versions of the human brain, but cell cultures the size of a ballpoint pen contain neurons capable of performing functions similar to those of the brain, forming a multitude of connections.
Scientists call this phenomenon "intelligence on a plate."
This enlarged image shows a brain organoid produced in Hartung's lab.
The culture was stained to show neurons in magenta, cell nuclei in blue, and other supporting cells in red and green.
(Courtesy: Jesse Plotkin/Johns Hopkins University)
Dr. Thomas Hartung, Professor of Environmental Health and Engineering at the Johns Hopkins University Bloomberg School of Public Health and Whiting School of Engineering in Baltimore, began growing brain organoids by altering samples of human skin in 2012.
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He and his colleagues envision combining the power of brain organoids into a type of biological
hardware
that is more energy efficient than supercomputers.
These "biocomputers" would use networks of brain organoids to revolutionize pharmaceutical testing for diseases like Alzheimer's, provide insights into the human brain, and change the future of computing.
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The research outlining the organoid intelligence blueprint laid out by Hartung and his colleagues was published Tuesday in the journal Frontiers in Science.
"Computer science and artificial intelligence have fueled the technological revolution, but they are reaching a limit," said Hartung, the study's lead author, in a statement.
"Bioinformatics is a huge effort to compact and increase efficiency to overcome our current technological limits."
The human brain versus artificial intelligence
Although artificial intelligence is inspired by human thought processes, the technology cannot fully replicate all the capabilities of the human brain.
This is why humans can use a completely automatic and public Turing test to differentiate computers from humans (CAPTCHA) from image or text as an internet security measure to prove that they are not robots.
The Turing test, also known as the imitation game, was developed in 1950 by British mathematician and computer scientist Alan Turing to assess how intelligently machines display human-like behavior.
But how is a computer really different from a human brain?
A supercomputer can process massive amounts of numbers faster than a human being.
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"For example, AlphaGo (the artificial intelligence that beat the world's number one Go player in 2017) was trained on data from 160,000 games," Hartung said.
"A person would have to play five hours a day for over 175 years to experience this many games."
On the other hand, a human brain is more energy efficient, as well as better at learning and making complex logical decisions.
Something as basic as being able to tell one animal from another is a task that the human brain easily performs and a computer cannot.
Frontier, a $600 million supercomputer from Tennessee's Oak Ridge National Laboratory, weighs in at a whopping 8,000 pounds, with each cabinet weighing the equivalent of two pickup trucks.
The machine in June surpassed the computing power of a human brain, but consumed a million times more energy, according to Hartung.
"The brain is still unmatched by modern computers," says Hartung.
"Brains also have an amazing capacity to store information, estimated at 2,500 [terabytes]," he added.
"We are reaching the physical limits of silicon computers because we can't fit more transistors on a tiny chip."
How could a biocomputer work?
Stem cell pioneers John B. Gurdon and Shinya Yamanaka received the Nobel Prize in 2012 for developing a technique that made it possible to generate cells from fully developed tissues such as skin.
The groundbreaking research allowed scientists like Hartung to develop brain organoids that were used to mimic living brains and to test and identify drugs that could pose risks to brain health.
Hartung has been working with brain organoids for years.
(Courtesy: Will Kirk/Johns Hopkins University)
Hartung remembers being asked by other researchers whether brain organoids could think or achieve consciousness.
The question led him to consider the possibility of giving organoids information about their environment and how to interact with it.
"This opens up research into how the human brain works," says Hartung, who is also co-director of the Center for Alternatives to Animal Experiments in Europe.
"Because you can start to manipulate the system, doing things that ethically cannot be done with human brains."
Hartung defines organoid intelligence as "the reproduction of cognitive functions, such as learning and sensory processing, in a laboratory-grown model of the human brain."
The brain organoids that Hartung currently uses would have to be expanded for organoid intelligence.
Each organoid has about the same number of cells as the nervous system of a fruit fly.
The size of an organoid is one three-millionth of the human brain, which is equivalent to about 800 megabytes of memory.
"They are too small, each containing about 50,000 cells. For organoid intelligence, we would have to increase this number to 10 million," he explains.
The researchers also need ways to communicate with the organoids to send them information and receive readouts of what they "think."
The study authors have developed a blueprint that includes bioengineering and machine learning tools, along with new innovations.
Allowing different types of input and output through the organoid networks would allow more complex tasks to be performed, the researchers write in the study.
"We have developed a brain-computer interface device that is a kind of EEG (electroencephalogram) cap for organoids, which we presented in a paper published last August," explains Hartung.
"It is a flexible shell densely covered with tiny electrodes that can pick up signals from the organoid and transmit them to it."
Hartung hopes that one day there will be a beneficial communication channel between artificial intelligence and organoid intelligence "that allows both to explore the capabilities of the other."
Ways to use organoid intelligence
According to the researchers, the most impressive contributions of organoid intelligence could be manifested in human medicine.
Brain organoids could be developed from skin samples from patients with neuronal disorders, allowing scientists to test how different drugs and other factors might affect them.
"With organoid intelligence we could also study the cognitive aspects of neurological conditions," says Hartung.
"For example, we could compare memory formation in organoids derived from healthy people and those with Alzheimer's, and try to repair the relative deficits. We could also use the organoids to test whether certain substances, such as pesticides, cause memory or learning problems. ."
Brain organoids could also open up a new avenue for understanding human cognition.
"We want to compare brain organoids from typically developing donors versus brain organoids from donors with autism," Lena Smirnova, co-author and co-investigator of the study and assistant professor of Environmental Health and Engineering at Johns Hopkins, said in a statement.
"The tools we are developing towards biological computing are the same ones that will allow us to understand changes in neural networks specific to autism, without having to use animals or access patients, so that we can understand the underlying mechanisms of why patients have these problems and cognitive deficiencies," he says.
The use of brain organoids to create organoid intelligence is still in its infancy.
Developing organoid intelligence comparable to a computer with the brain power of a mouse could take decades, according to Hartung.
But already there are promising results that illustrate what is possible.
Study co-author Dr. Brett Kagan, scientific director of Cortical Labs in Melbourne, Australia, and his team recently showed that brain cells can learn to play the video game Pong.
"His team is already testing it with brain organoids," says Hartung.
"And I would say that replicating this experiment with organoids already meets the basic definition of organoid intelligence. From here, it's just a matter of building the community, tools and technologies to harness the full potential of organoid intelligence."
The ethics of brain organoids
Creating human brain organoids capable of cognitive functions raises a number of ethical issues, including whether they can develop consciousness or feel pain, and whether the people whose cells were used to make them have any rights to the organoids.
"A fundamental part of our vision is to develop organoid intelligence in an ethical and socially responsible way," says Hartung.
"That is why, from the beginning, we have collaborated with ethicists to establish an integrated ethical approach. All ethical questions will be continually evaluated by teams of scientists, ethicists, and the public, as the research evolves."
Julian Kinderlerer, Emeritus Professor of Intellectual Property Law at the University of Cape Town, South Africa, says in a separately published article that it is essential to include the public in the understanding and development of organoid intelligence.
Kinderlerer was not involved in the new study on organoid intelligence.
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"We are entering a new world, where the interface between humans and human constructions blurs the distinctions," Kinderlerer wrote.
"Society cannot passively wait for new discoveries; it must participate in the identification and resolution of potential ethical dilemmas and ensure that any experimentation falls within ethical limits yet to be determined."
Watching the development of artificial intelligences like ChatGPT has caused some to question how close computers are to passing the Turing test, writes Gary Miller, associate dean for Research Strategy and Innovation and professor of Environmental Health Sciences at the University of Columbia of New York, in another Viewpoint article, published Tuesday.
Miller was not involved in the Johns Hopkins study.
Networks of brain organoids could one day be used to support biocomputers.
(Courtesy: Will Kirk/Johns Hopkins University)
Although ChatGPT can efficiently collect information over the Internet, it cannot react to a change in temperature like a cultured cellular system can, he wrote.
"Brain organoid systems could display key aspects of intelligence and sensitivity," Miller wrote.
"This requires a robust examination of the ethical implications of the technology, which must include ethicists. We must ensure that each step of the process is carried out with scientific integrity, while acknowledging that the most important issue It's the potential impact on society."
Artificial intelligence is blurring the line between human cognition and artificial intelligence, and technology and biology are advancing at a speed that could outpace necessary ethical and moral debates.
This emerging field must take a bold approach to addressing the ethical and moral questions that come with this type of scientific advancement, and it must do so before the technology crashes into the moral chasm."
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