By Jean Balchin 27/04/2018

In this week’s Nature, there is an intriguing op-ed about the ethics of growing or sustaining human brain tissue. We must consider the fact that researchers one day might be able to create a model in the laboratory that may be capable of what might appear to be conscious experiences. If this were to happen, it would raise a number of issues concerning ownership, stewardship, rights, disposal and data protection? To this end, Nita Farahany, Henry Greely and co-authors pose a number of difficult questions. 

In order to study disorders such as Parkinson’s disease and schizophrenia, researchers are growing miniaturized, simplified versions of human brain tissue from stem cells, called brain organoids.

“Brain organoids can be produced much as other 3D multicellular structures resembling eye, gut, liver, kidney and other human tissues have been built2–4. By adding appropriate signalling factors, aggregates of pluripotent stem cells (which have the ability to develop into any cell type) can differentiate and self-organize into structures that resemble certain regions of the human brain.”

These brain organoids are far from the hypothetical situation posed in the first paragraph. But it doesn’t take any stretch of the imagination to realise that someday, full brain models might be possible.

Another model type involves the use of slices of brain tissue that have been removed from individuals during some surgical procedure, for example to treat seizures. Such samples have been employed for more than a century in research, but technological advances, including in imaging and in the techniques used to preserve the functional properties of brain tissues in the lab (ex vivo), could make this approach considerably more powerful.

Other researchers have transplanted human brain cells into mice and some study brain tissue removed from patients during surgery. While these animal models are (and will remain) useful, most therapies for these diseases developed in animal models fail to work in people.

Laboratory models of the human brain could be enormously valuable,

“Yet the closer the proxy gets to a functioning human brain, the more ethically problematic it becomes,” argue Farahany and colleagues.

The authors discuss a number of issues that they think researchers, funders, review boards and the public ought to consider regarding this research. These issues include whether it is even possible for researchers to assess any sentient capabilities of a brain surrogate, as well as the potential for these to challenge our understanding of life and death.

Sentient capabilities of a brain surrogate might include being able to feel (to some degree) pleasure, pain or distress; being able to store and retrieve memories; or perhaps even having some perception of agency or awareness of self.

“To ensure the success and social acceptance of this research long term, an ethical framework must be forged now,” they conclude, noting that “experimental models of the human brain could help to unlock mysteries about psychiatric and neurological illnesses that have long remained elusive.”

You can read the full opinion piece here.