We Are Our Brains (51 page)

Pain stimuli follow two routes. In the lateral system they travel up the side of the spinal cord to the part of the cerebral cortex where sensory input is processed. Since this part of the brain is left largely intact by Alzheimer's, pain stimuli are received and processed as normal, and people with the condition have normal pain thresholds. The second route transports pain stimuli up the center of the spinal cord to the cingulate cortex, an alarm center and an area much damaged by Alzheimer's. This is the medial pain system, which processes the emotional aspects of pain. Since the lateral pain system functions properly, people with Alzheimer's experience pain, but because their medial system is damaged, they don't understand what is going on. So they respond in ways that we don't associate with pain. They frown or appear fearful or agitated.

The extent to which patients with dementia suffer pain, moreover, depends on the cause of their dementia. Patients with vascular dementia experience more pain through disruption of fiber systems in the brain, while patients with frontotemporal dementia lose the ability to process pain emotionally. It wouldn't be my own choice, but there are people with dementia who decide to carry on to the bitter end. In their case it's crucial to ensure professional diagnosis and treatment of their pain, because no scientific evidence has yet been found to support the notion that suffering is ennobling.

On the evening of Tuesday, November 11, 2008, Nan Rosens's impressive film
Before I Forget
was the subject of debate in the Rode Hoed cultural center in Amsterdam. The building was packed. In the documentary, Paul van Eerde explains that he doesn't want to experience the humiliation and loss of dignity that Alzheimer's entails. His wife and children support him in his difficult decision, and the family enjoys their remaining time together. However, the one person who doesn't endorse Paul's own choice is his family doctor. Paul isn't the only one to find out belatedly what his doctor's stance is. Whereas the vast majority of the Dutch population favors euthanasia, assisted dying, or the concept of a suicide pill, 91 percent of the population don't know their own family doctor's views on the matter. But that doesn't have to be the case. I know an eighty-year-old entrepreneur who moved to a new city and found a new doctor. The first thing he said to the doctor was, “I have two questions I'd like to ask you; one is more urgent than the other: How do you feel about abortion and how do you feel about euthanasia?” Unfortunately not everyone is comfortable being so assertive.

The second lesson of the film was that the doctor who didn't want to cooperate also didn't refer Paul to a colleague who would be prepared to help. We should start tackling this issue by training medical students properly and making sure that doctors get on-the-job training to deal with the difficult issue of euthanasia. It's essential for a patient to build up a good long-term relationship with their doctor
so that both parties can anticipate the right moment to end life. You can't start such preparation early enough, and making a living will while you're still in the peak of health is a good way to establish your doctor's views on euthanasia and to start to build the necessary relationship—or to determine that you need a different doctor.

In its earliest stage, dementia can only be reliably diagnosed by a memory clinic. Get a referral to such a clinic if you or your partner is worried about your memory. If you're diagnosed with early dementia, you must start to anticipate “the right moment.” It's natural to want to enjoy life as long as possible, but if you wait too long you will no longer be able to confirm your wish for euthanasia, and your doctor will be unable to help you. In the early stages of Alzheimer's, people are still mentally competent. After that they have lucid moments in which they are aware of their situation, but there comes a time when those, too, disappear. The former health minister Els Borst-Eilers said that she would want to end her life when she was unable to recognize her children and grandchildren. That's so late in the progression of the disease that it may create problems for a doctor. The right moment to end one's life is different for everyone and must be decided in close consultation with one's physician. Bear in mind that doctors, too, find this far from easy. The pioneer in the field of euthanasia, Sytske van der Meer, has said that she prefers the lethal substance to be given as a drink, because the patient has to drink it of his own volition, showing that he has stuck to his decision right up to the end. Others prefer a drip, because death then follows very quickly. This choice, too, must be properly discussed with the doctor. The debaters in the Rode Hoed agreed that the current euthanasia legislation provides more scope for assisted dying in early dementia than is commonly thought. To date, an assessment committee has judged thirty-five cases of euthanasia or assisted dying to have been conducted with all due care. This shows that the law gives doctors the protection they need. And awareness of this fact is fortunately increasing.

Life and death are hard to define. Life must meet certain criteria, like movement, metabolism, growth, independent reproduction (for which information-carrying molecules like DNA or RNA are needed), integration, and regulation. Although the last two characteristics can also be found in unicellular organisms, they only really came into their own when neurons evolved. In isolation, these characteristics
aren't proof of life. Flowing water moves, iron undergoes metabolic changes that we call rusting, a crystal can grow, and these days an increasing number of young people believe that life has more to offer
without
reproduction. Integration and regulation are characteristics that can also be programmed into a computer. A combination of all of these criteria must be present for life to be said to exist.

For centuries, doctors have based their pronouncement of death on the absence of a heartbeat and breathing and the assumption that those functions won't resume. After a few tense minutes, a doctor can be increasingly certain of his diagnosis. As a one-line Dutch poem entitled “Death” puts it, “Nothing you can do about it.” We were always taught that neurons are extremely sensitive to oxygen deprivation. After four or five minutes without oxygen, irreparable brain damage was said to result. And that's true, but it's the capillary cells, not the neurons, that are particularly sensitive to lack of oxygen. It makes them swell so much that even if the heart starts to beat again and breathing resumes within four to five minutes, the red blood cells can no longer get through the capillaries in the brain to give off oxygen. Moreover, in the stage that follows, toxic substances are released and the neurons ultimately die.

In “The Roller Coaster” (1953), a charming story about transplanting beautiful memories, the Dutch writer and doctor Belcampo predicted that by the year 2000 it would be possible to culture human neurons. Indeed, if the Netherlands Brain Bank receives postmortem tissue within ten hours of the donor's death, we can culture neurons in thin slices of brain tissue for weeks (
fig. 34
). In 2002, Ronald Verwer discovered that the cells in these slices are still able to produce proteins and to transport substances. They can also be electrically active. In fact, glial cells, which provide the support structure for the neural system, can even be cultivated from brain tissue a full eighteen hours after death.

Culturing slices of postmortem brain tissue shows that brain cells can survive ten hours of oxygen deficiency and that the death of an individual isn't the same thing as the death of his neurons. The question
of what life and death actually are becomes even more intriguing when one considers that these living cells are constructed from dead molecules like DNA, RNA, proteins, and fats. Would it be possible to create life from dead molecules? In 2003, Craig Venter made the first step in this direction by synthesizing a virus (Ph-X174) from dead material. But to reproduce, a virus needs the entire molecular machinery of the cell that it infects. Since a virus can't reproduce independently, occupying a space somewhere between living and dead material, Venter's experiment doesn't count as synthesizing life.

Full reincarnation can be said to exist at the level of molecular building blocks. Atoms have such a long life that each of our own atoms existed in many millions of organisms before being built into our bodies. So there's a good chance that your body houses atoms that were once part of a famous historical figure. Cells also contain water molecules, and these too are recycled. We drink water that once came from rivers. It leaves our bodies as urine, is purified, travels to the sea, evaporates, and then returns to our taps via rain and rivers. The biologist Lewis Wolpert calculated that the number of water molecules in a glass of water is so great (outnumbering the number of glasses of water in the sea) that there's a real likelihood of us drinking one that has been through, say, Napoleon's bladder. So our molecules have been constructed from hand-me-down atoms and are surrounded by water that has passed through countless bodies.

In principle, the molecular building blocks of life can be synthesized. The theory goes that if all the necessary molecules are brought together in the right way, life will appear as an emergent, new characteristic. That this is the case can only be proved by synthesizing, say, a living bacteria from dead material. In early 2008 Craig Venter synthesized the complete genome of the bacteria
Mycoplasma genitalium
, which involved over half a million building blocks. In 2010 he succeeded in getting the bacteria to replicate. After thirty cell divisions the original proteins were diluted out, so that the proteins of the cells were all produced by the synthetic genome. At the time
Venter estimated that the project to synthesize an entire bacteria would be complete by the end of that year. While he failed to meet this deadline, he certainly came closer to his objective. If he does eventually succeed, he can't be sure of a Nobel Prize, because creationists will surely claim that his experiment has been done before, citing a previous magical experiment described in Genesis 2:7, “Then the Lord God formed man of dust from the ground, and breathed into his nostrils the breath of life, and the man became a living being.”

Brain research has been conducted in Amsterdam since as early as the seventeenth century, although the context back then was rather different. Criminals who were condemned to death were hanged in the north of Amsterdam or on Dam Square. After execution, their bodies could be donated to the guild of surgeons for public dissection. The city authorities allowed such dissections to take place once a year (in winter, because they took three to five days, and the stench would have been unbearable in summer). Initially they were carried out in St. Margaret's cloister on Nes, where the Flemish arts center De Brakke Grond now stands. The guild chamber and dissecting room were located there from 1578 to 1619 and from 1639 to 1691, in the attic story of the meat market building. In the intervening period the surgeons' dissecting room moved to the Nieuwmarkt, above Amsterdam's weigh house. That is likely the place that inspired Rembrandt to paint
The Anatomy Lesson of Dr. Nicolaes Tulp
(1632), which now hangs in the Mauritshuis Museum in The Hague. The audience at public dissections consisted of a few hundred people who could afford the admission price of twenty cents. The heart,
liver, and kidneys were passed around among the spectators. The justification for using bodies to train surgeons can still be read on the wall of what used to be the anatomy theater: “Those who did wrong during their life become useful after their death.”

In 1656, Rembrandt records a crucial moment of such a dissection in his
Anatomy Lesson of Dr. Deijman
(
fig. 35
). The lecturer, Jan Deijman, stands behind the dissected cadaver of Joris Fonteijn, nicknamed “Black Jan,” a Flemish tailor turned thief who was condemned to be hanged on January 27, 1656. He was executed that same month,
probably on a temporary scaffold on Dam Square, in front of the old City Hall. His body was dissected at the surgeons guild in the former chapel of St. Margaret's cloister. Rembrandt's painting shows the assistant surgeon, Gijsbert Calcoen, patiently holding the top of the skull in which the brain will be deposited. Meanwhile, Dr. Deijman is using a pair of forceps to hold up the falx cerebri, the crescent-shaped membrane that separates the left and right cerebral hemispheres, thus exposing the pineal gland (
fig. 2
). The protocol required surgeons to do this, because in those days the pineal gland was thought to be the seat of the soul (as taught by Descartes), and as extra punishment the criminal's soul was made to see how the body had been dissected. Descartes lived in the Dutch Republic for nearly twenty years. He bought carcasses for his research at the cattle market near his lodgings, and his findings clearly left their mark on the Amsterdam of Rembrandt van Rijn.