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Disembodied pig brains and transplanted heads: new advances in science and the ethics of the brain

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It is with considerable difficulty that I remember the original era of my being; all the events of that period appear confused and indistinct. A strange multiplicity of sensations seized me, and I saw, felt, heard, and smelt at the same time; and it was, indeed, a long time before I learned to distinguish between the operations of my various senses."

And so begins the narration of the monster to its creator, Dr. Frankenstein, about the dawn of his existence. In her horror novel, Mary Shelley envisioned the traumatic event of coming to life and acquiring consciousness after death, hypothesizing it as a traumatic and overwhelming event for the conscious being.

The restoration of life after death is a topic that, together with the human aspiration to defeat death, has always dominated our culture. Such a topic has been relaunched last spring, after neuroscientist Nenad Sestan went to a meeting held at the National Institutes of Health on March 28 to report the work of his team at Yale University.

In the attempt to create a brain atlas, mapping neuronal connections, the team of Sestan succeeded in bringing back to functionality pigs’ brains collected from a slaughterhouse. The brains were brought back to “life” for up to 36 hours. Researchers restored circulation in the disembodied brains by keeping them connected to a system of pumps, heaters, and bags with artificial blood.

Already in 1993, the European Journal of Neuroscience published a work describing the whole brain perfusion of ex vivo guinea pigs’ brains. Such brains were found to have viable cells and a complex sensory system. Similarly, Yale’s researchers found billions of healthy cells exhibiting activity in the pigs’ brains. Nevertheless, EEG recordings showed no sign of brain activity but rather a flat brain wave, thus excluding the potential for regain of consciousness.

The news of a “brain resuscitation”, which is in fact very similar to the restoration of microcirculation in organs prepared for transplants, brought up the necessity for new ethical regulations on human brain experiments. Indeed, one month after the report of the work of Sestan’s lab, Nature published an editorial, on which Sestan himself is a signatory, identifying three different classes of human brain experiments which might need special control. First, brain organoids, a human induced pluripotent stem cells (hiPSCs)-derived experimental model consisting of 3D multicellular structures recapitulating human brain development. To date, organoids lack vascularisation and microglia, signifying that they probably cannot acquire consciousness at the current stage.

Second, human-animal chimeras, generated by transplantation of hiPSC-derived cells into the brains of experimental animals. Recent advances also permitted transplantation of brain organoids into the mouse brain, which subsequently became vascularised and integrated into the surrounding tissue.

Third, ex vivo human brain tissue, such as surgically removed samples from the brains of patients. They are used as tissue slices, thus lacking sensory inputs and indicating that they are not capable of perception or consciousness. Were it to be attempted on the entire human brain, also the restoration of circulation of ex vivo brains should be granted a spot in this list.

As mentioned above, one of the main issues is whether such “brains in a bucket” are capable of reacquiring awareness and consciousness. It is important to remember that they are completely disconnected from a body and, thus, incapable of receiving sensorial stimuli or “experiencing”. So, while Frankenstein's monster found himself overwhelmed by sensations such as seeing, feeling, hearing, and smelling all at the same time, it could be very different for a disembodied brain restored to life. It would probably be more like being trapped in a perceptionless box, or even to only be able to think and, in case the old memories from the pre-mortem life could be restored, reminisce. Something that could drive you totally crazy or extremely bored.

Similar issues could arise in the case of a head transplant, which is scheduled to be performed in China by the hands of an Italian and a Chinese surgeon. This new, dangerous procedure aims at taking the head of a patient, most likely affected by paralysis, and transferring it onto the body of a donor who died of traumatic brain injury. It has been hypothesized that, in case of a successful re-conjunction of the head to a different body, the brain would be overwhelmed by foreign signals coming from the new body (chemicals, hormones, electrical impulses) and might as well go crazy.

And so, the possibility of advanced studies, such as restoration of life to a disembodied brain or the transplantation of an entire head, should make us think about what this would all mean from the point of view of the consciousness and awareness of the existing entity - a highly uncharted territory. It could, in fact, result in the madness of such a conscious - yet incapable of communicating - being;  or else, it might lead to its mental torture due to the seclusion in the perceptionless box. Would you consider that worse than death, too?

Written by Chiara Galante; Edited by Fazi Bekbulat. Featured image NGC/Carine Thalman.


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