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Cerebral organoids: ethical issues and consciousness assessment
  1. Andrea Lavazza1,
  2. Marcello Massimini2,3
  1. 1Centro Universitario Internazionale, Arezzo, Italy
  2. 2Department of Biomedical and Clinical Sciences "Luigi Sacco", University of Milan, Milan, Italy
  3. 3IRCCS Fondazione Don Gnocchi Onlus, Milan, Italy
  1. Correspondence to Dr Andrea Lavazza, Centro Universitario Internazionale, via Garbasso 42, Arezzo 52100, Italy; lavazza67{at}


Organoids are three-dimensional biological structures grown in vitro from different kinds of stem cells that self-organise mimicking real organs with organ-specific cell types. Recently, researchers have managed to produce human organoids which have structural and functional properties very similar to those of different organs, such as the retina, the intestines, the kidneys, the pancreas, the liver and the inner ear. Organoids are considered a great resource for biomedical research, as they allow for a detailed study of the development and pathologies of human cells; they also make it possible to test new molecules on human tissue. Furthermore, organoids have helped research take a step forward in the field of personalised medicine and transplants. However, some ethical issues have arisen concerning the origin of the cells that are used to produce organoids (ie, human embryos) and their properties. In particular, there are new, relevant and so-far overlooked ethical questions concerning cerebral organoids. Scientists have created so-called mini-brains as developed as a few-months-old fetus, albeit smaller and with many structural and functional differences. However, cerebral organoids exhibit neural connections and electrical activity, raising the question whether they are or (which is more likely) will one day be somewhat sentient. In principle, this can be measured with some techniques that are already available (the Perturbational Complexity Index, a metric that is directly inspired by the main postulate of the Integrated Information Theory of consciousness), which are used for brain-injured non-communicating patients. If brain organoids were to show a glimpse of sensibility, an ethical discussion on their use in clinical research and practice would be necessary.

  • organoids
  • cerebral organoids
  • integrated information theory
  • perturbational complexity index

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  • Contributors AL and MM contributed equally to planning, conduct and reporting of the work described in the article. They are both responsible for the overall content as guarantors.

  • Funding This work was supported by European Union’s Horizon 2020 Research and Innovation Programme under Grant Agreement 720270 (HBP SGA1), James S. McDonnell Foundation Scholar Award 2013, EU Grant H2020-FETOPEN-2014 -2015-RIA 686764 Luminous and Canadian Institute for Advanced Research, Azrieli Program in Brain, Mind and Consciousness to MM.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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