The human brain has long been an inspiration for artificial intelligence (AI). This method has been incredibly successful: AI has achieved tremendous feats – from diagnosing medical conditions to producing poems. However, the original design still outperforms machines in many areas.

Recent advances in brain organoids derived from human stem cells promise to replicate critical molecular and cellular aspects of learning and memory and possibly aspects of cognition in vitro. This new interdisciplinary field is known as ‘organoid intelligence’ (OI).

A community of top scientists has gathered to develop this technology, which is said to usher in a new era of fast, powerful and efficient biocomputing.

Organoid intelligence requires various technologies to communicate with brain organoids.
Infographic: Organoid intelligence requires diverse technologies to interact with brain organoids CREDIT Frontiers/John Hopkins University

An example of cell culture grown in a lab is brain organoids. While brain organoids are not “little brains,” they share essential brain structure and function features, including neurons and other brain cells critical to cognitive processes such as memory and learning. In addition, organoids have a three-dimensional structure, while most cell cultures are flat. The cell density of the culture is increased 1000 times, allowing many more connections to be formed between neurons.

But even if brain organoids are good imitators of brains, why should they be good computers? After all, aren’t computers smarter and faster than brains?

Prof Thomas Hartung of Johns Hopkins University said: “While silicon-based computers are certainly better with numbers, brains are better at learning. For example AlphaGo [the AI that beat the world’s number one Go player in 2017] was trained on data from 160,000 games. Someone would have to play five hours a day for over 175 years to experience these many games.”

Brains not only learn better, they also use less energy. For example, more energy is put into teaching AlphaGo than it takes to support an active adult for ten years.

Hartung said, “Brains also have an amazing capacity to store information, estimated at 2,500 TB. We’re reaching the physical limits of silicon computers because we can’t fit more transistors into a small chip. But the brain is wired completely differently. It has about 100 billion neurons connected through more than 1015 connection points. It is a huge power difference compared to our current technology.”

Lab-grown brain organoid
A magnified view of a lab-grown brain organoid with fluorescent labels for different cell types. (Pink – neurons; red – oligodendrocytes; green – astrocytes; blue – all nuclei) CREDIT Thomas Hartung, Johns Hopkins University

“Current brain organoids need to be scaled up for OI. They are too small, each with about 50,000 cells. For OI, we should increase this number to 10 million.”

In addition, the authors are working on technology that will allow them to transmit the information from the organoids and read out what they are “thinking.” The authors plan to create new stimulation and recording devices and adapt techniques from other scientific fields, including bioengineering and machine learning.

Hartung said, “We have developed a brain-computer interface device that is a kind of EEG cap for organoids, which we presented in a paper last August. It is a flexible shell densely covered with small electrodes that can both pick up signals from the organoid and transmit signals to it.”

“Ultimately, OI would integrate a wide variety of pacing and recording tools. These will orchestrate interactions across networks of interconnected organoids implementing more complex computations.”

OI’s promise extends to both medical and computer science. Brain organoids can now be made from adult tissues thanks to a groundbreaking method by Noble Laureates John Gurdon and Shinya Yamanaka. This indicates that scientists can create custom brain organoids from skin samples from people with neurological disorders such as Alzheimer’s disease. Then they can perform various tests to examine how chemicals, drugs, and genetic factors may affect these conditions.

Hartung said, “With OI we could also study the cognitive aspects of neurological disorders. For example, we could compare memory formation in organoids from healthy people and Alzheimer’s patients and try to correct relative deficits. We could also use OI to test whether certain substances, such as pesticides, cause memory or learning problems.”

Complex ethical issues are being raised by the development of organoids in the human brain that can remember things and communicate with their environment. For example, could they attain consciousness even in a primitive form? Is there any pain or suffering for them? And what rights would individuals have over brain organoids made using their cells?

Hartung said, “An important part of our vision is to develop OI ethically and socially. That’s why we’ve been working with ethicists from the start to establish an ’embedded ethics’ approach. All ethical issues will continue to be reviewed by teams of scientists, ethicists and the public as research evolves.”

OI is still in its early stages, but a recently released study by Dr. Brett Kagan of the Cortical Labs, one of the paper’s co-authors, offers a proof of concept. His team showed that a normal, flat brain cell culture could learn to play the video game Pong.

Hartung added, “Their team is already testing this with brain organoids. And I would say that replicating this experiment with organoids already meets the basic definition of OI. From now on, it’s just a matter of building the community, the tools and the technologies to realize the full potential of OI.”

Magazine reference:

  1. Lena Smirnova, Brain Caffo et al. Organoid intelligence (OI): the new frontier in biocomputing and intelligence-in-a-dish. Frontiers in science. DOI: 10.3389/fsci.2023.1017235