After a simple dental operation, William lost the ability to remember anything. What happened to him? The answer to this medical mystery has the potential to change the way we think about the brain, says BBC Future.
William's internal clock stopped at 13.40 on March 14, 2005, during a visit to the dentist.
William, a British military officer, returned to his duty station in Germany the night before after driving home to attend his grandmother's funeral. In the morning, he visited the gym, where he played volleyball for 45 minutes. Then he went to his office to clean up the blockages of e-mails, and then went to the dentist, who had a root canal operation.
“I remember sitting down in the chair and the dentist injecting me with local anesthesia,” William told me. And then what? Complete emptiness.
Since then, he has not been able to remember anything for more than an hour and a half. And while he can still tell me about his first meeting with the Duke of York (Prince Andrew, brother of Prince Charles, heir to the British throne) at a Defense Department briefing, he can't even remember where he lives now. Every morning he wakes up with the feeling that it is 2005, he is in Germany and he has to visit the dentist.
Now, if he does not write down everything new that happens to him, the passage of time loses its meaning for him. The only thing he knows for sure today is that there is a problem, since he and his wife are leaving detailed notes on his smartphone in a folder entitled "Read this first."
Everything looks as if any new memories are recorded in invisible ink that slowly fade away. How could a minor dental surgery have such a profound effect on his brain? This real-life medical puzzle offers a rare insight into the hidden depths of the brain.
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Even the very events that led to the loss of William's memory seem very mysterious. During the operation, the doctor did not immediately realize that something was wrong. Only after the doctors asked William to take off his protective dark glasses did it become clear that he was completely pale and could hardly get to his feet. They called his wife.
“He was lying on the couch,” recalls Samantha (both spouses' names have been changed). - The eyes were fixed on one point; when he saw me, he seemed surprised; he had no idea what was going on at all."
By five o'clock in the afternoon he was transferred to the hospital, where he stayed for three days. Even after the mental fog had cleared a little, he still couldn't remember anything after a few minutes.
At first, the doctors suspected that he had responded poorly to the anesthesia, which caused a cerebral hemorrhage. However, they could not find any signs of injury. He was discharged, but the veil of secrecy continued to cover William's case and the family moved to England, where he was referred to Dr. Gerald Burgess, a clinical psychologist practicing in Leicester.
For William, every new day is like a blank sheet that must be filled with lost memories again.
The printing press in the brain
Most obvious explanation: William suffers from a form of anterograde amnesia, such as that of Henry Molison (1926-2008), known as N. M. or a Man without memory, to whom we owe much of what we now know about the properties of memory. During brain surgery in 1953 as an attempt to cure epilepsy, neurosurgeons led by William Scoville removed a lump of Molison's gray matter, including the hippocampus (the seahorse-shaped parts of the brain responsible for memory consolidation).
The hippocampus, which controls the function of internal organs, smell, memory and sleep in the limbic system of the brain, serve as a kind of memory printing press. They capture episodic memories of events by storing them in long-term storage. Having lost this part of the brain, Molison was unable to retain in his memory everything that happened after the operation.
At the same time, the first doctors who treated William noticed that these critical areas were not damaged on scans of his brain. He also did not exhibit the symptoms commonly seen in other patients with anterograde amnesia. Although Molison was unable to recall details of events in his personal life, he, for example, was able to master some procedural skills as they are processed elsewhere in the brain.
When Burgess suggested that William think about how to go through the difficult maze, he completely forgot the skill he had acquired three days ago. “It was like a deja vu copy of the same mistakes. It took him the same amount of time to learn how to solve the problem again,”Burgess says.
The hippocampus (marked in green) play a key role in processing memories
One explanation may be that William's amnesia is in the nature of a psychogenic illness. Some patients complain of memory loss after traumatic events, but this is usually a defense mechanism to avoid thinking about distressing events. This usually does not affect a person's ability to remember the present.
Samantha says that William did not suffer any trauma and was otherwise in complete emotional health. “He was an exemplary father and a promising military officer,” notes Burgess. "There was no reason to think there was anything wrong with him - psychiatrically."
Based on the available evidence, Burgess believes the clue lies in the midst of tiny neural connections, called synapses, that carry nerve impulses chemically from cell to cell. Once we have experienced a particular event, the memories of it are slowly cemented in the long-term memory system through changes in the intricacies of these complex networks.
The consolidation process is associated with the production of new proteins that are used to recreate synapses in their new form; without it, memory remains fragile and easily erodes over time.
Block the synthesis of these proteins in rats, and they will quickly forget what they just learned. An hour and a half is approximately the time during which the consolidation of memories in long-term memory occurs. It is after such a period of time that William begins to forget the details of the recent event.
Unlike Molison's brain, which, figuratively speaking, the printing press broke down, in William's case, it appears to have simply run out of ink.
But even in this case, it remains unclear how the operation on the root canal of the tooth caused such a "drying out" of his brain. "It's a million pound question," Burgess says, "and I don't have an answer." After studying the medical literature, he discovered five more cases of mysterious memory loss without brain damage.
While none of these cases involved a visit to the dentist, they appear to have occurred in the wake of periods of psychological stress caused by a medical emergency. “It could be a genetic predisposition that requires some kind of catalyst to start the process,” Burgess says.
Gerald Burgess hopes that his new article, published in May in the professional medical journal Neurocase, will encourage other psychologists to share information about similar cases, which may lead to insights and new theories. The colleagues in the scientific community are already intrigued.
"Yes, there is a lot to puzzle over," agrees Professor John Eggleton of Cardiff University in Wales, United Kingdom. He would like to see the results of more detailed tests in order to be able to look more closely at the chains of long-distance connections in the brain. Even if William's own brain cells are not damaged, he may be missing some of the necessary neural plexuses in the hippocampus and other segments of the entire memory processing highway, he believes.
In the meantime, William's case reminds us of how little we know about our own consciousness. Fascinated by the colorful MRI scans, many now imagine the brain as a kind of computer with individual chips responsible for memory, fear or sex. What happened to William perfectly demonstrates that this modular view of the mind is too primitive.
Even in those cases when all the mechanisms are outwardly in order, you can still find yourself lost in the present, unable to build a bridge from the past to the future. Obviously, the brain is made up of so many more layers that have to be removed one by one before we can get to the core of who we really are.
Every morning, William learns anew that his daughter and son are now 21 and 18 years old and are not the little children he remembers.
William also demonstrated how powerful emotions are in shaping our consciousness. Over the past 10 years, he has managed to grasp one new fact - the death of his father. In an inexplicable way, the power of grief helped him pave a new path in his brain and hold in his memory this sad event, while everything else slipped away. And yet, he cannot remember the events that accompanied his father's death, just as he cannot remember the vigils at the bedside of a dying man in his last few days.
When I spoke to him, he just learned - for the thousandth time - that his daughter and son are now 21 and 18 years old and are no longer the little children he remembers. William hopes that their future life will not be lost to him. “I want to take my daughter down the aisle and remember this. If they become parents, I would like to remember that I have grandchildren and who they are."
