Scientists Fear Mixing Tiny Human Brains with Animal Brains May Lead to ‘Chimeras’

As scientific breakthroughs continue to happen at breakneck speed, ethical questions that require serious, well-thought-out answers are popping up more and more frequently. One of the most interesting, and perhaps divisive, moral dilemmas for scientists stems from the question: How much human-brain capacity should be given to animals? And while the mere idea of smartening up animals with human brains seems absurd, it’s already happening to some extent in practice, and some researchers are now fearing the worst.

In a new perspective paper published in the journal Cell Stem Cell ( via Gizmodo), researchers at the University of Pennsylvania say that “Recent demonstrations of human brain organoid transplantation in rodents have accentuated ethical concerns associated with these entities, especially as they relate to potential ‘humanization’ of host animals.” That “humanization of host animals,” the abstract for the paper goes on to note, could lead to “human-animal brain chimeras,” which are essentially animal brains augmented with some level of human intelligence. (A “perspective paper,” by the way, is one in which a scientific opinion is provided, but not necessarily supported by evidence.)

Cerebral organoids like this one are raising ethical questions in the scientific community

NIH Image Gallery 

For those unfamiliar with what a “human brain organoid” is, go ahead and use your imagination to guess and you’ll probably land pretty close to the definition. As the name implies, a brain organoid, which is also known as a “cerebral organoid,” is very much like a tiny human brain. In fact, it seems cerebral organoids can be likened to the brain of a ten-week-old embryo, even though they’re grown in vitro from stem cells.

Considering the fact that these cerebral organoids are equivalent to very early stage human brains, as well as the fact that they are “most similar to layers of neurons [in] the cortex…” it makes sense that the researchers behind the paper, authored by H. Isaac Chen et al., believe that this particular area of advancement needs to be closely monitored for ethics violations. The idea of augmenting animals with human intelligence seems like an issue so important even the Pope may want to weigh in on it.

In the video clip above, Sarah Chan, a bio-ethicist at the University of Edinburgh who was not involved in this particular paper, outlines the concerns that scientists have regarding the implantation of cerebral organoids into animal brains. And while Chan notes that the scientific consensus is that mouse brains don’t have the “superstructure” required to develop human-level intelligence, she does note that scientists have already been able to smarten them up. Chan also adds that “it’s interesting to contemplate the prospect that we might make animals smarter through the use of human cells, and what sorts of possibilities that might open up for us to communicate with animals… [and have them] become more useful to us….”

What do you think of the ethics of human-animal brain chimeras? Will we ever be able to sit and have a philosophical conversation about this topic with say, a dog, or is the idea of a super-smart animal pure malarkey? Let us know your thoughts in the comments!

Feature image: NIH Image Gallery 

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