Can an artificial brain also generate consciousness?

Scientists are gradually approaching the ability to "grow" human brains in the laboratory, which has sparked ethical debates about the "welfare" of these laboratory-grown tissues.

At the core of the controversy are "brain organoids," which are sometimes mistaken for the "brains in a vat" from science fiction. In fact, these small pieces of brain tissue grown from stem cells are too simple to function like a real human brain. Therefore, the scientific community generally believes that brain organoids lack consciousness, resulting in relatively lenient supervision of related research.

However, not all scientists agree with this view.

Christopher Wood, a bioethics researcher at Zhejiang University, said: "We believe that under the influence of fear of hype and science fiction exaggeration, the academic community's stance has swung too far." Wood and his colleagues pointed out in a perspective article published in the journal Patterns [1] on September 12 that technological advancements may soon make "conscious organoids" a reality.

The authors believe that the relevant regulations on organoid research should be re-examined. Boyd Lomax, a neuroscientist at Johns Hopkins University, said that it is "immoral" to let conscious organoids develop their own thoughts or feel pain.

However, defining "consciousness" is not an easy task.

Consciousness is Difficult to Define

The stem cells used to create brain organoids grow side by side in a two-dimensional plane (such as a petri dish) and lack complex structural organization. But when they grow in suspension in a solid gel or a rotating bioreactor, they form a three-dimensional anatomical structure similar to the shape of an embryonic brain.

Although these organoids have three-dimensional features, many neuroscientists believe they are still too simple to possess consciousness. True brain consciousness stems from the communication between different brain regions, while organoids are only similar to a part of the brain. In addition, the existing "mini brains" are less than 0.16 inches (about 4 millimeters) in diameter, indicating that they lack the important structures required for consciousness.

People usually think that consciousness is the awareness of oneself by humans or animals. However, Andrea Lavazza, a moral philosopher and neuroethicist at the University of Pegaso in Italy, pointed out : "We believe that the consciousness of organoids is at the most basic level of perception, that is, the ability to feel pain and pleasure."

Alysson Muotri, a neuroscientist at the University of California, San Diego, said that most neuroscientists define consciousness as self-awareness or the ability to feel and experience something. But there is still no unified definition.

Some definitions associate consciousness with the ability to perceive the environment, such as vision or hearing. However, Lavazza pointed out that brain organoids are cultured in vitro and cannot receive these sensory signals. But in the future, more complex organoids may theoretically still experience pain. For humans, the meninges that surround the brain contain neurons that can transmit pain signals - which raises concerns that more complex organoids may also have similar abilities.

On the other hand, Lomax believes that "if an organoid has the neural structures representing pain inside, it can 'feel pain' without external signals." He pointed out that this is similar to the principle of "phantom limb pain" in amputees.

However, Wood pointed out that it is still unclear whether organoids can experience sensations similar to "phantom pain," as that may require the memory of a "lost limb." In short, this issue is very complex.

How to Measure Consciousness?

The perspective article points out that even in humans, scientists lack a good objective method to measure consciousness. Lavazza said that the only way to accurately detect consciousness is to directly ask individuals about their feelings. This does not mean that those who cannot communicate do not have consciousness, but it is much more difficult to accurately measure consciousness.

Lomax pointed out that in comatose patients or those with "locked-in syndrome" - a neurological disorder that causes total paralysis and makes communication extremely difficult - doctors usually rely on indirect signals (such as electroencephalogram activity) to judge consciousness. Based on these electroencephalogram signals, they can only infer whether the patient has consciousness, but cannot make a conclusive measurement.

Another method is called "perturbational complexity," which is used to evaluate the complexity of the brain signals generated after the brain is stimulated (for example, by a magnetic field acting on the scalp). Lomax explained that doctors generally believe that the more complex the neuron firing pattern, the more likely the patient is to have consciousness.

However, he also emphasized that some "indirect signals of consciousness," including perturbational complexity, can even be observed in neurons in a petri dish. This indicates that these indicators may not be reliable bases for judging consciousness.

Complexity Breeds Consciousness

Skeptics believe that brain organoids cannot generate consciousness because they lack sufficient structural complexity, including diverse cell types and vascular supply - which are crucial for complex signal transmission.

But Wood pointed out that in the next 5 to 10 years, technological advancements may enable scientists to grow more complex and potentially conscious organoids. A study in August this year [2] demonstrated a method to "implant" blood vessels into organoids; another study in September [3] found a way to introduce a new cell type - "microglia." Previously, scientists had also grown organoids with "primitive eyes" [4] or a "blood-brain barrier" [5].

Although existing organoids only represent a single brain region, neuroscientists can fuse multiple organoids into a "combination" to simulate the interaction between multiple brain regions. Lavazza pointed out that if these "combinations" have a neural network for pain perception, they may "feel pain" even without pain-sensing neurons.

Should the Regulatory Rules be Revised?

The regulations related to brain organoid research are relatively lenient partly because of the stance of the International Society for Stem Cell Research (ISSCR): the organization believes that these organoids cannot feel pain. Its guidelines state: "Currently, there is no biological evidence to suggest that there are issues worthy of concern, such as consciousness or pain perception, in organoids corresponding to central nervous system tissues. Therefore, there is no need for a special ethical review process."

But many experts believe that with recent technological breakthroughs, this stance should be re-examined.

Muotri pointed out: "The view of the ISSCR is too conservative. It should be revised by an interdisciplinary team (not just stem cell biologists)." Muotri himself is the founder of Tismoo, a company that develops brain organoids.

Part of the ethical concern is that organoids may feel pain or develop independent thoughts. Wood explained: "Once a conscious organoid is created, it becomes a morally significant entity, and its welfare must be considered."

Lavazza has a different view. "Personally, I don't think it is immoral to grow conscious organoids," he said. "After all, scientists also conduct experiments on other conscious organisms (such as mice)." Lomax believes that if organoids truly have consciousness, they should be regulated in a similar way to animal experiments.

Although a laboratory "brain" sounds like a plot from Brave New World, it may not be far from reality. How to evaluate consciousness and formulate corresponding regulations will be a tricky problem. Wood believes that instead of asking supporters to prove that organoids may have consciousness, we should ask skeptics to prove that they "definitely cannot" have consciousness.

At least, as he pointed out in the article, scientists should not rule out this possibility.

References

[1] Wood, C., Wang, H., Yang, W., & Xi, Y. (2025). Facing the possibility of consciousness in human brain organoids. PubMed, 6(9), 101365.

[2] Navarro, J. F., Crilly, S., Chan, W. K., Browne, S., Mason, J. O., Vallejo‐Giraldo, C., Pandit, A., & Lomora, M. (2025). Cerebral Organoids with Integrated Endothelial Networks Emulate the Neurovascular Unit and Mitigate Core Necrosis. Advanced Science.

[3] Lange, S., Ebeling, M., Loye, A., Wanke, F., Siebourg-Polster, J., Sudharshan, T. J. J., Völlmy, F., Kralik, J., Vidal, B., Hahn, K., Foo, L. C., & Hoeber, J. (2025). Human myelinated brain organoids with integrated microglia as a model for myelin repair and remyelinating therapies. Science Translational Medicine, 17(815).

[4] Gabriel, E., Albanna, W., Pasquini, G., Ramani, A., Josipovic, N., Mariappan, A., Schinzel, F., Karch, C. M., Bao, G., Gottardo, M., Suren, A. A., Hescheler, J., Nagel-Wolfrum, K., Persico, V., Rizzoli, S. O., Altmüller, J., Riparbelli, M. G., Callaini, G., Goureau, O., ... Gopalakrishnan, J. (2021). Human brain organoids assemble functionally integrated bilateral optic vesicles. Cell Stem Cell, 28(10), 1740-1757.e8.

[5] Dao, L., You, Z., Lu, L., Xu, T., Sarkar, A. K., Zhu, H., Liu, M., Calandrelli, R., Yoshida, G., Lin, P., Miao, Y., Mierke, S., Kalva, S., Zhu, H., Gu, M., Vadivelu, S., Zhong, S., Huang, L. F., & Guo, Z. (2024). Modeling blood-brain barrier formation and cerebral cavernous malformations in human PSC-derived organoids. Cell Stem Cell, 31(6), 818-833.e11.

Original article: https://www.livescience.com/health/neuroscience/tiny-brains-grown-in-the-lab-could-become-conscious-and-feel-pain-and-were-not-ready

This article is from the WeChat official account "Neural Reality" (ID: neureality). Author: Kamal Nahas, Translator: EY. Republished by 36Kr with permission.