Theoretical Neurobiology of Consciousness Applied to Human Cerebral Organoids.

Human cerebral organoids (HCOs), grown from stem cells to mimic developing brain tissue, may eventually manifest rudimentary consciousness, despite current limitations. Since HCOs provide no behavioral indicators of consciousness, this article applies three neurobiological theories—the Temporal Circuit Hypothesis, the Global Neuronal Workspace Theory, and the Integrated Information Theory—to assess whether HCOs could possess a neurobiological capacity for consciousness, analogous to how these theories are used with unresponsive brain-injured patients.

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Abstract

Organoids and specifically human cerebral organoids (HCOs) are one of the most relevant novelties in the field of biomedical research. Grown either from embryonic or induced pluripotent stem cells, HCOs can be used as in vitro three-dimensional models, mimicking the developmental process and organization of the developing human brain. Based on that, and despite their current limitations, it cannot be assumed that they will never at any stage of development manifest some rudimentary form of consciousness. In the absence of behavioral indicators of consciousness, the theoretical neurobiology of consciousness being applied to unresponsive brain-injured patients can be considered with respect to HCOs. In clinical neurology, it is difficult to discern a capacity for consciousness in unresponsive brain-injured patients who provide no behavioral indicators of consciousness. In such scenarios, a validated neurobiological theory of consciousness, which tells us what the neural mechanisms of consciousness are, could be used to identify a capacity for consciousness. Like the unresponsive patients that provide a diagnostic difficulty for neurologists, HCOs provide no behavioral indicators of consciousness. Therefore, this article discusses how three prominent neurobiological theories of consciousness apply to human cerebral organoids. From the perspective of the Temporal Circuit Hypothesis, the Global Neuronal Workspace Theory, and the Integrated Information Theory, we discuss what neuronal structures and functions might indicate that cerebral organoids have a neurobiological capacity to be conscious.