Written by: Devin Juros ‘23
Edited by: Jason Mero ‘22
The sacrifice of animals has always been an unfortunate consequence of medical science. To develop our new COVID-19 vaccines, chemotherapy treatments, and over-the-counter drugs, we often first test them on various animal models, like rats, dogs, and monkeys, with much justified ethical concern. Cell culture, a lab technique that involves growing cells in a petri dish, has developed as a possible alternative to animal experimentation, especially with new advances in growing cells to form 3D “organoids,” which are conglomerates of cells that functionally resemble human organs. However, recent research involving brain organoids grown in a dish yielded cells that resembled preterm human brains. This raises a new concern: whether we can and should grow consciousness from the bottom up. Is it actually possible to grow consciousness from cells in a dish? If so, is cell culture of brain organoids necessarily more ethical than animal experimentation?
Organoids are generated by putting human stem cells in a petri dish along with many other chemicals and nutrients to support cell growth. These cells divide, become heterogenous, and ultimately form complex groupings of cells that exhibit stability, self-renewal, and some functional aspects of a human organ . Organoids have been grown to resemble many human organs with the goal of studying diseases specific to those organs, including colon organoids to study celiac disease  and lung organoids to study asthma . Brain organoids have already been used to study several neurological disorders, including autism and schizophrenia . COVID-19 research has also utilized brain organoids to study which cell types and areas of the brain are most susceptible to infection by the virus . These organoids provide a flexible experimental model to study how a real organ might respond to certain diseases and treatments while being able to easily modulate the environment of the organoid.
As our cell culture techniques improve, it seems that the organoids we can grow become more and more similar to human organs. For a colon or lung organoid, this is ideal: the closer a lung organoid resembles a human lung, the more translatable medical findings are from the organoid to humans. For a brain organoid, a rather peculiar ethical dilemma seems imminent. As we grow brain organoids closer and closer to human brains, could these brain organoids become conscious?
There is evidence that suggests that these brain organoids are demonstrating some behaviors similar to those of human brains. For example, the Muotri Lab has developed brain organoids that live for several months, undergo cellular development resembling early human brain development, and exhibit brain activity akin to that of a preterm human . The Arlotta Lab has been able to grow brain organoids that develop photoreceptors, the light-sensitive cells in the retina that are involved in sight, that actually respond when light is shined on them by increasing their activity, much as the photoreceptors in your eye do when you look at something . From this, it certainly seems that brain organoids are becoming more like brains than the cells they came from. But, are they conscious?
The answer to this question is likely no for the time being, as the activity of these brain organoids is still relatively disorganized and sporadic. However, the possibility of consciousness emerging in the future in these brain organoids is certainly something to consider, and along these lines, the US National Academies of Sciences, Engineering, and Medicine has recently begun an investigation into ethical and legal issues related to brain organoids .
The biggest problem for solving these ethical questions surrounding consciousness in brain organoids is that we still do not have a single agreed upon definition of consciousness. Certain patterns of brain activity or behaviors are frequently cited as evidence of consciousness in animals, but brain organoid development may not exactly parallel human brain development. Discerning these patterns might be difficult, and it's hard to ascertain whether these patterns are even indicative of consciousness.
In the end, as with animal experimentation, it becomes a balance between the ethics of killing something that might be conscious and the ethics of delaying the development of new medicines for humans who are certainly conscious. We will have to wait to see if it is actually possible to grow consciousness in a dish through brain organoids, or rather if we can agree that these mini-brains are actually conscious. At the very least, it seems our advances in cell culture are leading to ethical concerns of the type that beset animal experimentation. Preemptively investigating the potential ethical concerns with this burgeoning field of research is imperative due to its rapid progress.
 3D Organoid Culture: New In Vitro Models of Development and Disease. (n.d.). Retrieved November 14, 2020, from https://www.sigmaaldrich.com/technical-documents/articles/biology/cell-culture/3d-organoid-culture.html
 Farahany, N. A., Greely, H. T., Hyman, S., Koch, C., Grady, C., Pașca, S. P., . . . Song, H. (2018). The ethics of experimenting with human brain tissue. Nature, 556(7702), 429-432. doi:10.1038/d41586-018-04813-x
 Human Colon Organoids. (n.d.). Retrieved November 14, 2020, from https://www.sigmaaldrich.com/technical-documents/protocols/biology/cell-culture/human-colon-organoids.html
 In Vitro Differentiation of Human iPS Cells into Airway Epithelial Lung Organoids for Respiratory Disease Research Applications. (n.d.). Retrieved November 14, 2020, from https://www.sigmaaldrich.com/technical-documents/articles/biology/cell-culture/human-lung-organoids.html
 Quadrato, G., Nguyen, T., Macosko, E. Z., Sherwood, J. L., Yang, S. M., Berger, D. R., . . . Arlotta, P. (2017). Cell diversity and network dynamics in photosensitive human brain organoids. Nature, 545(7652), 48-53. doi:10.1038/nature22047
 Reardon, S. (2020, October 27). Can lab-grown brains become conscious? Retrieved November 14, 2020, from https://www.nature.com/articles/d41586-020-02986-y
 Trujillo, C. A., Gao, R., Negraes, P. D., Chaim, I. A., Domissy, A., Vandenberghe, M., . . . Muotri, A. R. (2018). Nested oscillatory dynamics in cortical organoids model early human brain network development. doi:10.1101/358622
 Zhang, B., Chu, H., Han, S., Shuai, H., Deng, J., Hu, Y., . . . Huang, J. (2020). SARS-CoV-2 infects human neural progenitor cells and brain organoids. Cell Research, 30(10), 928-931. doi:10.1038/s41422-020-0390-x
[Image Citation] Fessl, S. (2019, December 11). Is It Ethical to Grow a Brain in a Petri Dish? Retrieved November 13, 2020, from https://daily.jstor.org/is-it-ethical-to-grow-a-brain-in-a-petri-dish/