What’s in it for me? Be awed by the power of the human brain.
What do a nurse who persistently hallucinates cartoon people; a mother whose own hand tries to strangle her, Dr. Strangelove-style; and a librarian who laughs uncontrollably for hours at a time all have in common?
They’re all crazy, right?
Actually, no. In most respects, all of these people are lucid, rational individuals with whom you could have a normal conversation. What they have in common is that they’ve all suffered damage to a portion of their brain, producing some odd – but ultimately predictable – symptoms.
Neurologists are interested in studying these exceptional people – not just because they have a morbid taste for the strange or deviant, but because exceptional brains have a lot to teach us about how “normal” brains function.
So, while these blinks might appear to be talking about the brains of others, they’re really talking about yours and about how it constructs every aspect of your experience – from your perception to your very identity.
In these blinks, you’ll learn
how the admiral Lord Nelson proved the existence of the soul;
which part of the brain lets you speak directly to God; and
a simple trick for bleaching your hair stark white.
Neurological disorders offer insight into the functions of each part of the brain.
Let’s begin with a thought experiment. Imagine a sort of futuristic helmet with a bunch of wires sticking out of it. When you place it on your head, it fires a powerful magnetic field onto a very small cluster of neurons in your brain – allowing you to activate any part of your brain at will. Actually, this isn’t science fiction. It is a real device called a transcranial magnetic stimulator.
So, let’s say you had access to one of these helmets. Which parts of the brain would you stimulate?
You could, for example, stimulate parts of the motor cortex to make your muscles twitch and flex of their own accord. Or you could stimulate the septum to induce pleasure more intense than the most exquisite orgasm. If you’re blind, you could even stimulate the visual cortex to experience what the sighted describe as “color.”
The key message here is: Neurological disorders offer insight into the functions of each part of the brain.
The point is, whatever part of the brain you chose to stimulate, you’d experience something different. And that’s because the various parts of the brain each have a different purpose.
For example, despite their symmetry, we now know that the left and right hemispheres of the brain are radically specialized for distinct tasks.
The left hemisphere is responsible for, among other things, most aspects of language formation – from the comprehension of meaning to the actual production of sounds. By contrast, the right hemisphere is relatively ineloquent, although it is involved in the more creative aspects of language like nuance and allegory.
Unfortunately, many discoveries about the functions of parts of the brain were only made after something went terribly wrong. For example, the reason we know that the hippocampus plays an essential role in the formation of new memories is that doctors, as a last resort, once decided to surgically remove the tiny, seahorse-shaped structure from an epileptic patient’s brain. After the operation, the patient was no longer capable of forming new memories, although he remembered everything that had happened prior to surgery.
This tragedy resulted in an important discovery – and doctors treat the hippocampus with much more respect because of it. Obviously, experimental surgery that disables patients in the process is far from an ethical research methodology.
That’s why neuroscientists study neurological disorders; they afford an opportunity to examine unique brains without causing any damage.
Phantom limb syndrome is caused by a misalignment between our internal body image and the physical body.
John was an aspiring athlete until he lost one of his arms in a car accident. But, though his arm was gone, John continued to feel as though it were still there, even years later. He could wave it around, scrunch his fist in frustration, and even grab objects in the world around him. Once, the author picked up a coffee cup that John was holding in his phantom hand, and John yelped in pain: “Oww! Hey, don’t do that, that hurts!”
John has what’s called a phantom limb. Phantom limbs are like the ghostly memory of an appendage that continues to endure, sometimes for decades, after the physical limb was lost. Most reported cases of phantom-limb syndrome involve an arm or leg, although other phantom appendages – including phantom breasts and phantom erections – have also been reported.
The key message here is: Phantom limb syndrome is caused by a misalignment between our internal body image and the physical body.
So, what’s the nature of these ghostly appendages?
Well, Lord Nelson, a famous admiral, declared that his phantom arm was direct evidence for the existence of the soul. After all, he claimed, if an immaterial arm can survive the loss of the physical limb, why couldn’t an immaterial form survive the loss of the entire body?
In a sense, Lord Nelson had a point. It turns out, we all have a sort of internal body image that’s distinct from the physical body. For most of us, our body image and our actual bodies are so thoroughly integrated that we tend to take for granted that they’re the same thing– while cases of phantom-limb syndrome show that there is actually a difference. We have good reason to think these phantoms couldn’t survive the total loss of the body – for they’re very much dependent on our brains.
If you look at the surface of the frontal lobe in the brain, you’ll find a vertical strip of tissue called the motor cortex, which is responsible for facilitating movement by sending signals to the muscles. Thanks to magnetic resonance imaging, we know that a representational map of the entire human body is laid out, upside down, on this strip of tissue.
Why do phantom limbs occur? Well, our best explanation is that the area of the brain responsible for controlling the limb continues to send it signals, even after it's gone.
In other words, the representational map and the actual, physical body don’t match up.
Perception involves many different processes – and not all of them are conscious.
When Ellen returned home from the hospital, her family immediately noticed that something was wrong. The hair on one side of her head was combed; on the other, it was knotted into clumps. Her shawl hung only over one shoulder; the rest trailed on the floor. And, most disconcerting of all, she was wearing lipstick and mascara on just one side of her face.
Ellen was exhibiting a syndrome called hemi-neglect, which can be characterized as a profound indifference to the left side of the world. It’s not that she was blind, technically. It’s that she was utterly indifferent to anything that happened on the left side of her visual field. It was as if, for her, “leftness” just didn’t exist.
The key message here is: Perception involves many different processes – and not all of them are conscious.
It’s not exactly clear what’s going on in the minds of patients like Ellen. But what we do know is that hemi-neglect only occurs after a patient has suffered a stroke to the right parietal lobe, which indicates that this area plays an important role in perception.
Admittedly, that’s not saying much. There are about 30 areas of the brain involved in perception, and we don’t know what most of them do. Unfortunately, this is another situation where we only figure out how things work when they go wrong. For example, we know that the middle temporal area is responsible for processing movement because a Swiss woman was no longer able to perceive motion after receiving damage to this area. To her, a car driving down the street would appear as a strobe-like series of static images.
So, what’s going on in Ellen’s case?
Well, it seems like the right parietal lobe must be responsible for a kind of perception. People with typical brain function possess an internal “searchlight” that’s able to scan the visual field and fall upon specific objects. This searchlight ability seems to be lacking in hemi-neglect patients.
But, remarkably, studies suggest that many of these patients’ other perceptual processes continue to function. For example, patients faced with a picture of a house that was on fire only on the left side invariably said they wouldn’t want to live in it – even though they couldn’t explain why.
The implication is that not all the processes involved in perception are involved in conscious awareness. It seems parts of our brain are “seeing” without keeping us in the loop.
What we might see as “delusions” are rational from the perspective of a patient’s altered reality.
When Arthur was a student, he received a severe blow to the head in a near-fatal car accident. For weeks, he lay in a coma. After he awoke, he embarked on the usual grueling path toward rehabilitation – gradually relearning to walk, talk, and recall the past. Miraculously, he was able to make a full recovery, although there was one small problem: he declared his parents had been replaced by imposters, and no amount of evidence or persuasion could convince him otherwise.
Arthur had acquired Capgras syndrome – a delusion wherein the sufferer believes their loved ones have been replaced by duplicates. Arthur admitted that these duplicates looked just like his parents, but he insisted they really weren’t.
The key message here is: What we might see as “delusions” are rational from the perspective of a patient’s altered reality.
Capgras syndrome is usually directed at close relatives, but other people, animals, or even things can be perceived as “replaced.” For example, one patient believed his pet poodle was an imposter. A much more tragic and grisly case involved a patient who, believing his stepfather to be a robot, decapitated him and opened his skull in search of microchips.
Most would be tempted to conclude that these patients are acting irrationally. Certainly, from our perspective, they are. But for a neurologist, this dismissive attitude doesn’t help explain why these patients manifest such a specific delusion. For a neurologist, the salient issue is to find out what has changed in a patient’s brain that would make such a delusion seem rational from the patient’s perspective.
Our biggest clue to understanding what’s going on comes from studies that measure changes in the galvanic skin response, or sweat, on the palms of patients’ hands when they look at familiar faces. Capgras patients exhibit no change whatsoever when they see an image of their mother. This indicates a total lack of response from the limbic system, which isn’t typical behavior.
It’s possible that the emotional response elicited from the limbic system by a familiar face plays a part in helping the brain identify who we’re looking at. So when Arthur looks at his mother and feels absolutely nothing toward her, perhaps the way the brain makes sense of this contradiction is to conclude that this person isn’t really his mother.
If this interpretation is correct, then it explains how the “duplicate” delusion might seem rational to a brain not receiving the emotional feedback that a loved one is present; in this case, the familiar face must be a copy.
Many delusions are neurological, rather than psychological, in origin.
Mrs. Dodd had grown impatient with her doctors. Why were they insisting that her left arm was paralyzed when she knew she could move it just fine?
In fact, she could not move her arm. Mrs. Dodd was completely paralyzed on the left side of her body after a stroke to the right hemisphere of her brain. However, it didn’t seem to bother her much; despite having spent the last two weeks in a wheelchair, she seemed blissfully unaware of her predicament and denied it vehemently.
When the doctor asked her to touch his nose with her left arm, the limb remained limp and motionless. But that didn’t stop Mrs. Dodd from exclaiming: “There, I’m touching it!” Asked to clap her hands, Mrs. Dodd merely raised her right arm and silently swung it in the air.
Mrs. Dodd was displaying an extreme form of anosognosia: the inability to perceive one’s own illness.
The key message here is: Many delusions are neurological, rather than psychological, in origin.
But what’s going on here? Is this really a neurological disorder? Isn’t the problem more psychological? Mrs. Dodd seems to be suffering from extreme denial in the face of a traumatic event. Perhaps her response is simply a psychological defense mechanism.
In some cases, there may well be a psychological component to denial. The author recalls a patient who was tragically diagnosed with terminal brain cancer. Strangely enough, the man didn’t seem concerned about the diagnosis at all; instead, he spent much of his time complaining about a blister on his forehead. On the face of it, this example seems like a clear-cut case of deflection – the mind’s attempt to divert attention away from overwhelming stress and toward more manageable problems.
While psychological explanations for denial are certainly relevant in many cases, we have reason to believe there’s a neurological basis for denial, at least in some severe cases.
The fact is, patients who exhibit anosognosia have almost always suffered a stroke to the right hemisphere of the brain. Tellingly, those who suffer a stroke to the left hemisphere actually exhibit opposite tendencies – they’re prone to obsess over their illness and fret over their chances of recovery.
In the future, we might well discover that a great many psychological problems actually have their root in neurological damage. Since traditional therapy isn’t likely to be effective in repairing physical problems, we could potentially save patients countless wasted hours on the couch.
The human brain has an innate propensity for spiritual experiences.
Not all neurological disorders have a negative impact on a person’s life. In fact, every now and then, you meet a person whose so-called “disorder” has profoundly transformed their life for the better.
Enter Paul. Paul was an assistant manager at his local Goodwill store. But in his spare time, he liked to read, write, and have conversations with God.
Paul began hearing God in his early teens – around the same time he started having epileptic seizures. During his seizures he felt immersed in a bright light, gripped by a serene clarity, and filled with a sense of oneness with the Creator of all things. These experiences were so rapturous that he had no interest in sex; it paled in comparison.
The key message here is: The human brain has an innate propensity for spiritual experiences.
Our understanding of seizures tends to be limited to the muscular variety – violent, involuntary contractions of the muscles that can cause someone to fall to the ground and convulse. These are known as grand mal seizures, and they occur when the entire brain is engulfed by a storm of electrical activity. But seizures can also be localized. If the electrical disruption happens in the limbic system, then the symptoms will be predominantly emotional.
Patients like Paul who have these emotional sorts of seizures report symptoms ranging from incomparable ecstasy to fits of extreme terror, rage, or despair. But the most profound experiences that can occur are spiritual in nature. Patients recount feeling a divine presence and deep connection to the cosmos.
Now, whether these patients genuinely are, or are not, experiencing communion with the divine is a question for another time. The point is that we have neural circuitry in our brains that, when stimulated, tends to induce profound, metaphysical experiences. Could it be that humans have evolved specialized neural circuitry for the sole purpose of facilitating the mystical – just as we have specialized circuitry for understanding language or perceiving color?
It’s possible this capacity to experience the spiritual conferred some kind of evolutionary advantage on our ancestors. But at present, we’re not able to conclude whether the brain evolved specifically to have these kinds of experiences, or if they’re just an accidental by-product of circuitry that developed for another purpose.
Either way, a truly exciting aspect is that questions of spirituality, which have traditionally been the territory of religion, may soon be addressed by science.
Even laughter, with all of its cultural associations, is the product of specialized networks in the brain.
Willy loved his mother deeply, and he grieved heavily when he heard the news of her passing.
When the day of her funeral came around, he performed every solemnity that you would expect. He donned a crisp black suit, spoke lovingly at the funeral service, and mourned with his family at the open grave where his mother was to be buried. It wasn’t until his mother’s casket was being lowered into the earth that Willy began to laugh.
At first it was only a hushed snicker, but it soon became a giggle. He clasped his hand to his mouth, trying to smother his mirth, but to no avail – he soon exploded with a hearty laugh. He kept laughing until he was doubled over and, in that bent position, he desperately tried to stagger away. The other attendees could only watch, mouths agape.
The key message here is: Even laughter, with all of its cultural associations, is the product of specialized networks in the brain.
Willy had experienced an outburst of compulsive laughter. Cases are rare in the medical literature, but what we know is that compulsive laughter is almost always associated with abnormal behavior in the limbic system, a cluster of structures involved in producing emotions.
That said, it’s not exactly clear what caused Willy’s limbic system to malfunction so strikingly. Could it have been caused by the shock of his mother’s death? To answer that question, we need to explore what this strange paroxysm of sound – laughter – is actually for.
Some evolutionary psychologists speculate that laughter first developed in our ancestors as a form of communication. They suggest that laughter might have served to alert others in a group that a potential threat was actually a false alarm. The laugh signals to everyone simultaneously that there’s really nothing to worry about – we can all relax.
Of course, this theory doesn’t account for all the nuanced functions of laughter in today’s society. But perhaps once this primordial laughter structure was in place, it was co-opted for other functions. This is a very common evolutionary strategy. Feathers, for example, were originally developed in birds for insulation; only later were they adapted for use in flying.
So maybe laughter is like the feather. It originally developed for something simple, like helping the group to relax after encountering a potential danger in the wild. Later on, it evolved to trigger relaxation when faced with other stresses, too. That would explain why so many jokes are about sensitive topics, like sex and death.
And it might also explain poor Willy’s outburst. Perhaps his uncontrollable laughter was an exaggerated response from his “false alarm” system in an attempt to relax him after a traumatic experience.
Western medicine needs to study the mind-body connection more.
The year was 1932, and Mary Knight was nine months pregnant. She had felt the baby kicking for a while now, and she knew it was nearly due. But, as money was tight, Mary had put off seeing a doctor. She only made a visit to Dr. Monroe when she felt she was close to delivering.
During the check-up, everything looked as it should. Mary’s abdomen was enlarged, her breasts were swollen, and her nipples were mottled. But something wasn’t right. Her navel wasn’t pushed out. When the doctor put his stethoscope to her belly, he couldn’t find the baby’s heartbeat. Had she miscarried? No, she hadn’t. As it turned out, there had never been a fetus at all.
The key message here is: Western medicine needs to study the mind-body connection more.
Mary had a case of pseudocyesis, or phantom pregnancy. This is a real, albeit quite rare, disorder that still affects women today. They develop all the physical symptoms of a real pregnancy – their menstruation stops, lactation begins, they even feel morning sickness. But there’s one critical difference: there’s no fetus.
Pseudocyesis is a curious syndrome because it seems to be a case of the mind acting on the body in a profound way. It seems to occur only in women who have a deep desire to be pregnant or, conversely, a deep desire not to be. This desire produces actual bodily symptoms of pregnancy, which then reinforce the woman’s belief that she is pregnant.
It’s also further cause to examine the relationship between the mind and the body. If the mind can conjure a pregnancy, what else can it do?
The medical literature is full of similarly strange, and sometimes dubious, cases of apparent mind-body interaction – for instance, cases of people’s hair turning stark white after a terrible fright. There are cases of people with a pollen allergy suffering a reaction after exposure to a plastic flower. There are even instances where warts have fallen off the body after hypnosis.
Western doctors have been generally skeptical of mind-body interaction, and they’re quite right to be. Skepticism is healthy in science and truly a virtue in scientific inquiry. However, when skepticism takes the form of an unjustified prejudice against unusual ideas, then it may actually obstruct potentially useful research.
It’s time that scientists let go of their prejudices against mind-body interaction and, instead, submit these claims to rigorous testing.
Final summary
The key message in these blinks:
We take many of the most fundamental aspects of reality for granted. But they’re not so much inherent in the world “out there” as they are imposed on our experience by our brain. As we’ve seen, even basic concepts like “left” and “right” can vanish when the brain is damaged. How our brain functions also affects other aspects of our experience, including our sense of “oneness” with our body, feelings of familiarity with friends and family, and foundational aspects of culture such as spirituality and laughter.
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What to read next: The Man Who Mistook his Wife for a Hat, by Oliver Sacks
If you relished the fantastic and sometimes disturbing world of extreme neurological conditions, check out our blinks to the classic of clinical storytelling, The Man Who Mistook his Wife for a Hat.
These blinks recount many more stories from the clinic – extraordinary tales of almost otherworldly aberrations of the mind. You’ll learn about extreme delusions, altered perceptions, and out-of-control appendages. The aim of these blinks, beyond the intrigue, is to raise awareness and sympathy for people struggling to exist in altered realities quite unlike your own.