Current brain organoids are different in size and maturity from normal brains. More importantly, they do not produce any behavioral output, demonstrating they are still a primitive model of a real brain. However, as research generates brain organoids of higher complexity, they will eventually have the ability to feel and think. In response to this anticipation, Associate Professor Takuya Niikawa of Kobe University and Assistant Professor Tsutomu Sawai of Kyoto University's Institute for the Advanced Study of Human Biology (WPI-ASHBi), in collaboration with other philosophers in Japan and Canada, have written a paper on the ethics of research using conscious brain organoids. The paper can be read in the academic journalNeuroethics.

Working regularly with both bioethicists and neuroscientists who have created brain organoids, the team has been writing extensively about the need to construct guidelines on ethical research. In the new paper, Niikawa, Sawai and their coauthors lay out an ethical framework that assumes brain organoids already have consciousness rather than waiting for the day when we can fully confirm that they do.

"We believe a precautionary principle should be taken," Sawai said. "Neither science nor philosophy can agree on whether something has consciousness. Instead of arguing about whether brain organoids have consciousness, we decided they do as a precaution and for the consideration of moral implications."

To justify this assumption, the paper explains what brain organoids are and examines what different theories of consciousness suggest about brain organoids, inferring that some of the popular theories of consciousness permit them to possess consciousness.

Ultimately, the framework proposed by the study recommends that research on human brain organoids follows the ethical principles similar to those for animal experiments. Therefore, recommendations include using the minimum number of organoids possible and doing the upmost to prevent pain and suffering while considering the interests of the public and patients.

"Our framework was designed to be simple and is based on valence experiences and the sophistication of those experiences," said Niikawa.

This, the paper explains, provides guidance on how strict the conditions for experiments should be. These conditions should be decided based upon several criteria, which include the physiological state of the organoid, the stimuli to which it responds, the neural structures it possesses, and its cognitive functions.

Moreover, the paper argues that this framework is not exclusive to brain organoids. It can be applied to anything that is perceived to hold consciousness, such as fetuses, animals and even robots.

"Our framework depends on the precautionary principle. Something that we believe does not have consciousness today may, through the development of consciousness studies, be found to have consciousness in the future. We can consider how we ought to treat these entities based on our ethical framework," conclude Niikawa and Sawai.