01. June 2008 · Comments Off on Albert Einstein's brain and information-theoretic death · Categories: Death, Neuroscience, Science · Tags: , , ,

People like you and I, though mortal of course like everyone else, do not grow old no matter how long we live…[We] never cease to stand like curious children before the great mystery into which we were born.”

Albert Einstein

One sign of the lack of faith in the future progress of technology and the poor acceptance of the neurological basis for mind is the way in which our society treats the “post-mortem” human brain.

In some cases, the brains of those whom modern medicine cannot help are removed after cardiopulmonary arrest and donated (by the permission of the patient or the family) for research. In such cases, the brains are preserved so they can be studied over a long period of time. They are also sectioned and prepared in other ways for examination. Such donated brains have helped scientists learn about the human brain, with an eye to improving methods for treating conditions such as Alzheimer’s or mental illness. However, other brains have been preserved mainly because they belonged to famous people.

One of the more famous cases is the brain of Albert Einstein, removed in 1955 and preserved apparently without his or his family’s permission, and then made available for study. According to an NPR report, Einstein’s brain was fixed, sectioned into over 200 blocks, embedded in celloidin, and then stored in formalin.

Since that time, Einstein’s brain has been further sectioned and divided among researchers. A 1985 study by Diamond et al. reported that the Einstein brain sections’ neurons were still observable, and the study’s authors even assumed the number of neurons preserved in Einstein’s brain would be the same as those in recent preserved brains.

Presumably, people have wanted to study the brains of famous people in order to learn something about what made those people special. Turning a person into a mere object of study is a questionable notion, though, and the idea that the study could yield any information about the person’s mind underscores how it is widely accepted by scientists that the brain instantiates the mind, and thus the person.

Neuroscience is still too much in its infancy to make much sense of the evidence of the brain, as the scientific reception to the Diamond study showed. We do not yet know how to “read” the brain for the specific memories and personality traits and other phenomena of mind stored in it. However, because we do know enough now to know that the mind arises from the brain, we must realize that to preserve the brain is to preserve the potential of mind, and to preserve the potential of mind is to preserve the possibility of life for the person whose brain it was.

The neural basis of personhood sits ill with older notions such as immaterial souls or spirits. The neural basis of personhood also fits poorly with existing medical and public policies such as commonly accepted definitions of death and laws related to end of life. If death is understood as irreversible damage to certain identity-critical areas of the brain, the irreversibility of such damage is put into question by every advance in the treatment of injury and disease of the brain, as well as by the brain’s mysterious ability to recover from conditions such as minimally conscious state after many years. The cardiopulmonary-arrest definition of death does not involve the condition of the brain, and the usual definitions of brain-death do not distinguish between identity-critical areas or aspects of the brain and other areas or aspects of the brain. A more rigorous definition of personal death has been developed by Ralph Merkle, who states:

“A person is dead according to the information-theoretic criterion if their memories, personality, hopes, dreams, etc. have been destroyed in the information-theoretic sense. That is, if the structures in the brain that encode memory and personality have been so disrupted that it is no longer possible in principle to restore them to an appropriate functional state then the person is dead. If the structures that encode memory and personality are sufficiently intact that inference of the memory and personality are feasible in principle, and therefore restoration to an appropriate functional state is likewise feasible in principle, then the person is not dead.”

Although there is still some lack of clarity about the “etc.” and “appropriate functional state”, this definition of death at least is founded on the neural basis of personhood. Those who believe in the future progress of technology and accept the neural basis of personhood are led inevitably to understand that preserving the brain is preserving the person, potentially for later resuscitation.

It is not impossible to imagine that, in a more advanced future time, the formalin-fixed, celloidin-embedded brain sections could be reassambled, and if the synaptic circuitry of the neurons were well preserved, any significant damage could be repaired. The brain might be able to be returned to a viable state by reversal of the fixation and removal of the celloidin embedding. Resuscitation of an isolated brain would be unacceptable, but eventually it might be possible to restore the rest of the body around the brain by cloning or regeneration of the cells or some other prosthetic embodiment.

As amazing as it may seem, a patient reduced to a preserved brain, whose mind would be in a stopped state, might be able to be healed, that is, totally restored to a healthy body and a mind which could resume the life it left off, with all the memories and personality intact.

The case of Albert Einstein’s brain is unfortunate. All the impudent cutting, handing around, and tampering with Einstein’s brains sections, and the crude preservation method, may have irreversibly damaged the neural basis of his personhood. Yet we do not know enough today about the brain to know how much of it needs to be preserved, and in what state, to be able to revive a person with future technology. The preservation of the brain, though, would provide a theoretical possibility of future resuscitation. It may not be possible to someday restore Albert Einstein from the remains of his brain, but if it were possible, those in possession of the brain sections would first have to be willing to consider whether their “specimens” might be the restorable fragments of a still potentially living person who deserves to live more than to be studied.

25. February 2008 · Comments Off on Biostasis through chemopreservation · Categories: Cryonics, Death · Tags: , , , ,

Twenty years ago, Charles B. Olson published an article called “A Possible Cure for Death” in the journal Medical Hypotheses. In it, he favorably compares methods of chemical preservation to cryogenic preservation. Unfortunately, this article provoked no wide discussion or attempts at implementation. As the author notes on his website, other than requests for reprints, “nothing more came of it.” And yet the arguments in it are still sound and just as persuasive today as they were then. Why the reluctance?

Freezing has a certain subjective appeal. We freeze foods and rewarm them to eat. We read stories about children who have fallen into ice cold water and survived for hours without breathing. We know that human sperm, eggs, and even embryos can be frozen and thawed without harm. Freezing seems intuitively reversible and complete. Perhaps this is why cryonics quickly attained, and has kept, its singular appeal for life extensionists.

By contrast, we tend to associate chemical preservation with processes that are particularly irreversible and inadequate. Corpses are embalmed to prevent decay for only a short time. Taxidermists make deceased animals look alive, although most of their body parts are missing or transformed. “Plastinated” cadavers are used to demonstrate surface anatomy in schools and museums. No wonder, then, that cryonicists routinely dismiss chemopreservation as a truly bad idea. Although from time to time chemopreservation is raised as a possible alternative to cryonics (Perry, page 21-24), to this day it has not been given the full consideration it deserves

Part of the confusion around chemopreservation concerns the quality of preservation that is possible with this method. Chemical methods of preservation such as fixation are not only adequate, they have long been the gold standard for biologists studying the structure of cells and the brain. As Olson notes,

The technological advances in the preparation of tissue for microscopy have directly improved the prospects of brain preservation for reanimation. This is not a coincidence: the goals of microscopy and brain preservation for reanimation are fundamentally similar. In both cases, a maximal amount of structural detail is preserved such that information can be extracted.

When fixed immediately and properly embedded in a solid medium, tissue can preserve physical structure indefinitely. The entire brain can begin to be fixed by arterial perfusion within minutes after pronouncement of death. Fixation can be done by hospital pathologists or funeral home specialists. The brain can then be impregnated with a solid-setting polymer so that it becomes fully inert.

But what of reversibility? Olson dismisses the need for reversibility. The information in the brain can be retrieved and run on a different substrate — a new organic or machine brain. However, K. Eric Drexler’s proposal in Engines of Creation, nanoscale mechanical repair, could also apply to chemopreserved brains just as to cryopreserved brains. The damage caused by fixation and embedding might be able to be reversed just as the damage caused by freezing or vitrification, if, in both cases, identity-critical information preserved in the brain has not been lost.

If personal identity is preserved in the brain in physical structures such as synaptic circuits, then we know that chemopreservation can preserve these structures just as well as cryopreservation. In fact, chemopreservation entirely avoids the danger of ice formation and fracturing, which in theory could destroy physical structures in the brain and cause irretrievable identity-critical information loss. While fixatives cause molecular changes in the brain, by crosslinking and denaturing proteins, cryoprotectants also cause chemical damage which must later be repaired. While it is not certain that chemopreservation can preserve all identity-critical information, it is also not certain that cryonics stabilization, cryoprotection, and vitrification preserve all identity-critical information.

For those who accept the method of resuscitation by scanning the brain and running it its processes on a different substrate (“mind uploading“), chemopreservation might present additional benefits. The chemopreserved brain, unlike the cryopreserved brain, is ideally suited to microscopic extraction of information:

The molecules in a chemopreserved brain have been extensively crosslinked and can be embedded in a plastic which was designed for electron microscopy. Consequently they will be resistant to the heat and damage generated by whatever beam of particles (or other investigative device) is used to determine the details of the internal structure. In contrast, a frozen brain is not particularly prepared to resist damage, and is acutely sensitive to any heat generated.

But even for those who prefer mechanical repair of the brain, chemopreservation presents benefits that cryopreservation does not.

First, it is potentially cheaper, because it does away with the need for expensive long-term care. Chemopreserved patients would not require labor to keep them in the same condition, other than storage in a secure, designated area, unlike cryopreserved patients who are in continual danger of thawing. Cryopreserved patients require continual monitoring of liquid nitrogen levels and topping off with more liquid nitrogen, as well as special, expensive containers that can hold liquid nitrogen, and these containers need regular maintenance, repair, and replacement. Liquid nitrogen also presents hazards that require continual air monitoring and alarms.

The basic techniques for chemopreserving a brain — fixation and polymer impregnation — would also not require the services of specially trained volunteers or professionals; they are routine techniques used in hospital pathology labs and departments of anatomy around the world. As Olson notes, “the cost of brain chemopreservation could be less than that of a typical funeral.”

People are routinely turned away from cryonics providers because they cannot afford cryopreservation. So what are we waiting for?