Human cerebral organoids and consciousness: surveying relevant theoretical neurobiology

As explained in the previous chapter, human brain organoids are organoids that resemble parts or aspects of the human brain, and human cerebral organoids (HCOs) are one type of brain organoid that mimics the cerebrum. They can be described as miniature 3D biological models of the cerebrum derived from human embryonic or induced pluripotent stem cells. Insofar as these organoids accurately resemble the cerebrum in early development, they can advance our understanding of how this part of the human brain develops and propel neurological progress. But given that they resemble a part of the human brain thought to corresponds to consciousness, the research development and use of HCOs elicit a question with substantial ethical implications: Can these brain organoids become conscious? Whether HCOs could become conscious depends on two factors. The first factor, which was addressed in the previous chapter, is how consciousness relates to the brain. The second factor, which is addressed in this chapter, is whether or not the neurobiological conditions for consciousness are present in the organoids. To this second factor, Owen et al. (2024) applied three neurobiological theories of consciousness: the Temporal Circuit Hypothesis, the Global Neuronal Workspace Theory, and the Integrated Information Theory. This chapter extends their work by applying several additional theoretical frameworks: Higher-Order Thought Theory, the Attention Schema Theory, as well as Predictive Processing and Neurorepresentationalism. After introducing each theory, we consider what it implies about the neurobiological conditions that HCOs need to meet in order to become conscious.