Could a clump of interlocking brain cells in a petri dish ever experience self-awareness? Can you partially humanize a mouse or a monkey by implanting human stem cells in their brain? When parts of the brain of a dead person are revived in a laboratory, is the patient still completely dead?
Questions like these are raised by cutting-edge, state-of-the-art neuroscience techniques. Although they seem so far-fetched, they force scientists to turn their heads around what it takes to be a human brain.
Neuroscientists may not yet create conscious mini-brains in their labs. But this perspective, though far away, is real. And as things stand now, scientists may not really know when they've crossed that blurry line.
So it's not too early to think about scenarios that have more to do with science fiction thrillers than real life, a group of 1
In laboratories around the world, scientists have used stem cells to grow multicellular structures that resemble human organs. including eye, intestine, liver and kidney. Now the same techniques are used to breed brain "organoids" – miniaturized, simplified versions of living brain tissue.
Brain researchers transplant these organoids or the human stem cells from which they are derived into other animals to study the function of brain tissue removed from just-deceased people, or from patients with brain tissue removed to treat diseases such as epilepsy to treat.
The knowledge gained from this research will help brain scientists at a very basic level how this complex organ develops, how its components function individually and together, and what goes wrong with certain psychiatric and neurological disorders
Unfortunately, the renunciation of this research would probably be unethical, the authors of the New Essay wrote: But going forward also has its ethical dangers.
"Ensuring long-term success and social acceptance of this research is an ethical fracture Work must now be forged," wrote the experts who met at Duke University's Science and Society Initiative last May, to work out a list of concerns.
Most of these brain organoids live in growth medium in a laboratory dish and have no blood supply and specialized cells needed for basic household functions. They consist of about 2 to 3 million cells (a mature human brain has about 170 billion) and are no larger than about an adult fruit fly.
But these organoids are tiny facsimiles of a part of a human brain. They are already grown and fused into "assemblages" of brain structures. It is hard to imagine that researchers could one day create a miniaturized model of the exquisitely complex organ that can create, store and retrieve memories, love and hate other living beings and view their own place in the universe.
Scientists have already transplanted organoids of the human brain to rodents. In a short time, the accumulation of human brain cells whipped up the neurons of their hosts, and rodent neurons seemed to return the embrace. Indeed, the researchers found evidence of crossovers between the human organoid and the rodent brain that had become their host, according to a study published in Nature Biotechnology this month.
In related works, neuroscientists have already used human stem cells to grow glial cells (a type of brain cell involved in brain cleaning) and transplanted them into the brains of mice. For certain learning tasks, the hybrid mice performed better than their counterparts, which were 100 percent mouse.
Meanwhile, researchers from the Yale School of Medicine (including neuroscientist and essay co-author Dr. Nenad Sestan) reportedly restored blood flow to the brains of decapitated pigs and kept the revived organs "alive" for up to 36 hours. , Although the swine brains showed no signs of consciousness, the experiment indicated that the brain cells could be capable of normal activity upon death of their host, with sufficient propensity.
And in Harvard, the stem cell biologist Paola Arlotta (also one of the essays Englisch: bio-pro.de/en/region/stern/magazine/…2/index.html The authors developed 31 human brain organoids over periods up to For nine months, they observed how pluripotent stem cells formed human retinal cells alongside other brain cells, and when their team shed light on the retinal cells that grew in a lab bowl, they effectively "blinked" the brain cells in response to "an external stimulus becoming one ] Nature .
Complete this time with time, academic ambition, and scientific advances, and you begin to appreciate the issues raised in the paper:  Should be brain organoids or nonhuman beings that carry human brain cells, protected by regulations that increase the possibility of their larger Acknowledge consciousness?
Should this possibility exclude the formation of chimeras that affect our close evolutionary relatives, such as chimpanzees or monkeys?
Who owns the organoids or animals produced by these processes, and what do the human owners of stem cells or brain tissue say in their later use? Should there be limits to the ability of human tissues to live outside their original owner?
"There are so many issues that we need to think about," said Henry T. Greely, who co-authored the essay with the Duke bioethicist Nita Farahany
Another outstanding business: how to define consciousness Attribute that would certainly warrant greater protection for the organoids and other organisms believed to have it
"The signals for awareness or unconsciousness of living adults who use electroencephalography (EEG) electrodes, for example 'Do not necessarily have to be infants, animals or experimental brainsets,' the group wrote. "Without knowing more about what consciousness is and what building blocks it needs, it might be hard to know which signals to look for in an experimental brain model."
Greely, a lawyer who directs Stanford University's program in neuroscience and society, said the thorniest ethical issues are not immediate. "But I think in 5 to 10 years there is a really good chance we have to ask," Are we there yet? "
The best evidence that it is time to discuss these issues is the active involvement of scientists at the front of such work," said Greely. Usually "it's a reflex" to resist discussions that could severely limit their work.
"You are all convinced that these ethical concerns are really important," said Greely. "That's a pretty strong signal for me."
Ethics debate overdue in human brain research: experts