What is neuropreservation?
Neuropreservation is preservation of the brain of a cryonics patient by the best means possible. Those means now include an advanced technology called vitrification that eliminates freezing injury. The goal of neuropreservation is to restore the patient to health by regrowing a new body around the brain using future tissue regeneration technology.
Doesn’t preserving only a brain make revival more difficult, and cryonics less likely to work?
Where cryonics is concerned, all cryonics patients have injuries that will require highly advanced technology to repair. Tissue regeneration, as complex as it is, is arguably a simpler problem than other needed repairs. While not preserving the body appears drastic, it is objectively a less serious injury than other injuries that occur during cryopreservation.
The brain is the most essential organ in the human body. All other tissues and organs can theoretically be replaced. In cryonics, the technology that best preserves the brain is therefore the technology that best preserves the life of the patient. There have been times in the history of cryonics when neuropreservation preserved the brain better than whole body preservation, such as between the years 2001 and 2005 when brain vitrification was only available for neuropreservation patients.
Why do people choose neuropreservation?
Neuropreservation is less expensive than whole body preservation. Neuropatients cost less to maintain than whole body patients, and can be moved much easier in emergencies. Disease, aging, and cryopreservation cause damage to almost every cell of a whole-body patient. Future physicians may decide that the best way to reverse this damage will be to regrow a young, healthy body around the repaired brain of a cryonics patient rather than devise separate repair strategies for all the different organs and tissues of the body. In both nature and industry, replacement of damaged parts is usually easier than repair. If so, then the extra money spent for whole body preservation today may be wasted.
Newer more advanced preservation technologies are often made available for neuropatients before whole body patients. For example, for several years vitrification was only available for neuropatients. Only recently did new technology make brain vitrification possible during whole body cryopreservation.
The quality of brain preservation in whole body patients may not be as good as for neuropatients. Cryoprotectant absorption of the entire body is measured during whole body cryopreservation. During neuropreservation, cryoprotectant absorption of each brain hemisphere is individually measured and optimized without interference from the rest of the body.
Are there other advantages to neuropreservation?
Yes. Alcor is currently testing storage systems to reduce or eliminate tissue fracturing injury in cryonics patients. These systems, which involve storing at temperatures warmer than liquid nitrogen, will be probably available for neuropatients years before they are for whole body patients. New and improved cryonics technologies are often available for neuropatients before whole body patients.
Are there any disadvantages to neuropreservation?
With neuropreservation, the mapping information of how nerves in the brain connect to specific muscles and senses in the body is lost. While basic connection patterns are determined by genes, it’s likely that many details are individualized like fingerprints and conditioned by life experience. It may be possible to recover this information by a high level analysis of memories within the brain, but this is speculative. Neuropatients may therefore require physical rehabilitation.
How is neuropreservation done?
The goal of neuropreservation is to preserve the whole brain without injury. The brain is therefore preserved within the head to avoid injuries that removal would cause. This has the additional advantage of preserving the nerve connections of our most complex senses (vision and hearing). “Neuroseparation” is performed by surgical removal of the body below the neck at the level of the sixth cervical vertebra at a temperature near 0ºC. (This leads to the mistaken belief that neuropreservation preserves “heads,” but the preservation target is really the brain.) The cephalon (head), is then perfused with cryoproectants via the carotid and vertebral arteries prior to deep cooling. For neuropatients cryopreserved before the year 2000, neuroseparation was performed at the end of cryoprotective perfusion via the aorta.
What happens to the non-preserved portion of the body after neuropreservation?
It is disposed of in accordance with member wishes, usually by cremation at Alcor’s expense. A closed-casket memorial service followed by cremation or burial is also possible. These arrangements can be made with a funeral director chosen by the member or his/her family in accordance with their religious preferences.
Neurological research banks remove donated brains from deceased persons for medical research without "neuroseparation," so why can’t Alcor do the same?
Neurological research banks usually dissect brains for research, so injury during removal is permissible. In cryonics, it would be unethical to injure a brain by removing it from the skull for purely aesthetic purposes.
How, exactly, will neuropreservation patients be recovered?
In the future medicine will learn to master growth and development programs within the human body. Cells will be reprogrammed to heal severed spinal cords, regrow lost limbs, and even regenerate new organs. This kind of tissue regeneration already occurs naturally in children that lose fingertips, and in organs such as the liver. Extending these regenerative capabilities will be a matter of uncovering old programs that may still be dormant in our genes, and eventually writing new programs. In cases of severe injury, it is possible to imagine placing patients in a fluid support environment in which blood is artificially circulated to maintain life until vital organs are regenerated and all injuries healed. Such a healing process could theoretically start with just a brain. Programming a brain to regrow a new body may seem incredible, but nature already does things that are even more incredible. The body you have right now is the product of a growth program that started from a single cell.
How do I explain neuropreservation to my friends and family?
One of the advantages of neuropreservation is that remains can be returned for memorial services. Unless you choose to, there is no reason to tell anyone about your cryonics arrangements except your medical doctor and immediate family. For those whom you choose to tell, a variety of approaches are possible. In some cases, you might simply say that you’ve made plans to donate brain tissue for scientific research (all cryonics patients are legally anatomical gifts). In other cases, you might say you have cryonics arrangements with Alcor without specifying further details (recommended approach for health care providers). For your family and close friends, you can tell them how some scientists believe that someday all cryonics patients may be revived starting only from their brain, and that therefore preserving the brain makes the most sense scientifically and economically. Rather than wasting money for something that is less likely to work, it makes the most sense to carry the most important part of you forward into the future in the best possible way.
Do I need to tell my doctor about neuropreservation?
Your physician and institutions caring for you need to know that you are an Alcor member, especially if you are seriously ill. However they do not need to know that you have chosen neuropreservation. Alcor recommends that you don’t discuss neuropreservation with health care providers. Stabilization and transport procedures are identical for all Alcor patients. The final preservation option that you select is a confidential matter between you, Alcor, and your immediate family. Neuropreservation is prone to sensationalization and misunderstanding that can jeopardize medical cooperation with cryonics cases.
Is vitrification of the brain always successful?
No. Sometimes, especially if a cryonics patient is not immediately stabilized after cardiac arrest, cryoprotectant chemicals may not circulate well through the brain. Instead of vitrification, partial freezing may occur inside patients cryopreserved under poor conditions.
Can brains that are successfully vitrified be revived now?
No. Vitrification as currently implemented by Alcor is morphological vitrification, which means that cell structure is preserved well, but not necessarily cell viability. Current vitrification solutions are toxic to cell biochemistry by an unknown mechanism. However the toxic effects may be minor and ultimately reversible in light of published studies showing that small organs can survive exposure to similar solutions. Chemical mixtures permitting successful preservation of both structure and viability of large organs must await future breakthroughs in the field of organ preservation. The eventual application of such technologies to the human brain will be an unprecedented medical breakthrough – a scientifically certain way to preserve human lives indefinitely.
Will whole body preservation ever be a superior option to neuropreservation, possibly resulting in earlier revival?
Yes, eventually. A turning point will be reached when preservation of the whole body, including brain, becomes so good that tissue regeneration begins to look like a hard problem compared to tissue repair. At that point, whole body preservation will be better than neuropreservation. Alcor therefore advises young members to purchase sufficient life insurance for whole body preservation even if choosing neuropreservation now.
Isn’t neuropreservation bad public relations?
Neuropreservation is a powerful reminder that cryonics is really about preserving information, not appearances, and that cryonics in all forms still requires distant future technology to succeed. To the extent that neuropreservation educates people about the harsh scientific realities of cryonics, it is good public relations. Promotion of whole body preservation based on the idea that because it looks better it must be better, is misleading. In the long run, truth is the best public relations. At Alcor, we will keep telling the neuropreservation story as long as it takes for people to understand it.