Clusters of brain cells, so-called brain organoids, have been bred in the biologist’s lab at the University of California, San Diego. According to the New York Times, the scientists altered human skin cells into stem cells, then “coaxed them to develop as brain cells do in an embryo”. “The organoids grew into balls about the size of a pinhead, each containing hundreds of thousands of cells in a variety of types, each type producing the same chemicals and electrical signals as those cells do in our own brains.” (NYT, 29 August 2019) The progression was stimulated by various means. A few days ago, the scientists reported that they have recorded simple brain waves in these organoids. “In mature human brains, such waves are produced by widespread networks of neurons firing in synchrony. Particular wave patterns are linked to particular forms of brain activity, like retrieving memories and dreaming.” (NYT, 29 August 2019) Someday it may be possible to use brain organoids to develop inverted or reversed cyborgs. Another method could be to take an adult brain from a deceased creature. There is no doubt that many interesting philosophical questions arise in this context, such as the boundaries between humans and machines and the rights of such cyborgs.
Chimeras in the biological and medical sense are organisms that consist of cells or tissues of different individuals and yet form closed and viable (not necessarily reproductive) organisms. They can be located within a species or between species and can be both plants and animals. There are natural (blood chimeras in mammals) and artificial mixed organisms (grafting in plants, animal-human embryos). Cyborgs are not chimeras in this sense. Nevertheless, research in this field might also be relevant for them, in particular for inverted or reversed cyborgs, for example robots in which an animal or human brain or organ is implanted. Animal-human chimeras for the production of human organs are regarded as unproblematic by many ethicists. According to a comment by Oliver Bendel, this is astonishing, since findings from animal ethics and veterinary medicine and in particular suffering and death of non-human living beings are ignored.