Ethics debate overdue in human brain research: experts

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What if human brain tissue implanted into a pig transferred some of the donor's self-awareness and memories?

Such a scenario, out of reach for now, is becoming more and more conceivable, according to a group of scientists, ethicists, and philosophers who called Wednesday for a debate on the ethics of storing and using human brain matter.

Brain "surrogates" composed of real human cells—whether in tiny organoids grown in the lab, in grey matter removed from a human patient, or brain tissue implanted into animals—are crucial for studying the organ that allows us to think.

But there are risks, 17 experts warned in a comment published in the science journal Nature.

"As brain surrogates become larger and more sophisticated, the possibility of them having capabilities akin to human sentience might become less remote," they wrote.

"Such capacities could 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."

There is a need, the group argued, for "clear guidelines for research", and for special oversight committees.

They pointed to a study in which scientists noted "neural activity" after shining light on a region of a human "organoid" with eye and .

Organoids are rudimentary, 3-D structures grown from human stem cells and used to mimic features of a developing organ to study disease and disability.

The authors pointed to another study in which tiny, human brain organoids—implanted into the brains of mice—survived and communicated with the host brain.

"Without knowing more about what consciousness is, and what building blocks it requires, it might be hard to know what signals to look for" in experiments, the letter states.

One solution, it proposed, could be for researchers to use anaesthesia to keep animals with human brain tissue in a comatose state.

"Perhaps certain brain functions or a pre-specified level of brain activity, signalling a lack of capacity, could be used to delineate ethically justifiable research."

Such difficult questions should not halt critical research, the team underlined.

Brain surrogates can help unlock the mysteries of psychiatric and neurological illnesses.

"But to ensure the success and social acceptance of this research long term, an ethical framework must be forged now, while surrogates remain in the early stages of development."

Explore further

Researchers grow capillaries with a neural organoid

More information: Debate ethics of growing or sustaining human brain tissue outside the body, Nature (2018).
Journal information: Nature

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Apr 25, 2018
There is no magical boundary where an animal becomes self-aware. There is a gradient of consciousness. I would not be too worried about a cluster of human brain cells living inside an animal. Even if the mass of cells had the ability to develop human level consciousness (it doesn't) it would take years of growth and learning. Brains of fully developed animals are more self-aware than immature human brains.

If the animals approach human level consciousness after years of research has allowed almost completely human brains to grow and replace the original brain, then we will surely know this has happened by observing the animal, and a decision can be made then. And if an animal has to live it's life as an almost-human in an animal's body, it's far from the worst tragedy ever. People suffer daily all around the world in worse ways. There's nothing saying that a self-aware animal would not enjoy living in it's animal body (the only one its ever known), just as we enjoy living in ours.

Apr 27, 2018
There is no magical boundary where an animal becomes self-aware. There is a gradient of consciousness.

Not necessarily. That's assuming conciousness is an elaboration of a simpler mechanism in the brain, a difference in quantity rather than a difference in quality.

But neural networks can work in variety of ways, they can form a simple and direct "transfer function" that maps inputs to outputs, or they can have various levels of internal and external feedback loops, and internal representations of sensory data, or any combination, all representing a different paradigm of operation.

When the networks evolve/learn to perform tasks, the first thing they do is elaborate on the existing structure. A direct transfer network simply adds more conditional states - but as the task gets harder this eventually fails and the network has to change in type.

It's like, if you need to lift a bigger stone, you use a longer lever, but eventually you'll need to invent a pulley.

Apr 27, 2018
Point in case: even humans aren't conscious all the time, and even when we are conscious we're usually conscious only of a limited amount, and in general we are more than capable of performing "automatically" for extended periods of time.

With careful observation it's also possible to catch yourself operating automatically, although people are usually frightened by this - since the common belief is that the conscious you is the boss. We say "my brain is doing...", instead of saying "me the brain is doing..."

In reality the automatic you is doing most of the things most of the time and that's more "you" than the commentator's voice in your head that says "I am doing this". It's not unreasonable then that most animals would have no such commentator at all - why would they?

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