It’s time to consider the ethics of creating brains in labs
Could a clump of interlocking brain cells in a Petri dish ever experience selfawareness? Can you make a mouse or a monkey partly human by implanting human stem cells in its brain? If pieces of a dead person’s brain are reanimated in a lab, is the patient still completely dead?
Questions like these are being raised by advancing techniques at the cutting edge of neuroscience. Far-fetched though they may seem, they are forcing scientists to wrap their heads around what it takes to be a human brain.
Neuroscientists may not yet be creating conscious mini-brains in their labs. But that prospect, while distant, is real. And as things stand now, scientists may not truly recognize when they have crossed that indistinct boundary.
So it’s not too early to ponder scenarios that seem to have more in common with sci-fi thrillers than real life, according to a group of 17 neuroscientists and medical ethicists who made their case recently in the journal Nature.
In labs across the world, scientists have used stem cells to grow multicellular structures that resemble human organs, including the eye, gut, liver and kidney. Now the same techniques are being used to grow brain “organoids” — miniaturized, simplified versions of living brain tissue.
Brain scientists are transplanting these organoids, or the human stem cells from which they are grown, into other animals. Elsewhere, they are probing the function of brain tissue excised from people who have just died, or from patients who have had brain tissue removed to treat diseases such as epilepsy.
The knowledge gleaned from this research will help brain scientists understand at a very basic level how this complex organ develops, how its components work individually and together, and what goes wrong in certain psychiatric and neurological disorders.
“To ensure the success and social acceptance of this research long term, an ethical framework must be forged now,” wrote the experts.
Most of these brain organoids live in growth medium in a lab dish and lack the blood supply and specialized cells needed for basic housekeeping functions.
Yet these organoids are tiny facsimiles of part of a human brain. Already, they are being grown and fused into “assemblages” of brain structures.
Add time, academic ambition and scientific progress to these instances and you begin to appreciate the questions raised in the essay:
Should brain organoids, or non-human creatures bearing human brain cells, be protected by regulations that acknowledge the possibility of their greater awareness?
Should that possibility preclude the creation of chimeras that involve our close evolutionary relatives, such as chimps or monkeys?
Who owns the organoids or animals created by these processes, and what say should the human owners of stem cells or brain tissue have in their subsequent use? Should there be limits on the ability of human tissues to “live” outside of their original owner?
“There are so many issues we need to think about,” said Henry T. Greely, who drafted the essay along with bioethicist Nita Farahany.
The best evidence that the time has come to discuss these matters is the active engagement of scientists at the front lines, Greely said. Usually, “it’s a reflex” to resist discussions that might place strictures on their work.