The inescapable fact is that the brain is an unnerving place as well as a marvelous one. There seems to be an almost limitless number of curious or bizarre syndromes and conditions associated with neural disorders. Anton-Babinski syndrome, for instance, is a condition in which people are blind but refuse to believe it. In Riddoch syndrome, victims cannot see objects unless they are in motion. Capgras syndrome is a condition in which sufferers become convinced that those close to them are impostors. In Klüver-Bucy syndrome, the victims develop an urge to eat and fornicate indiscriminately (to the understandable dismay of loved ones). Perhaps the most bizarre of all is Cotard delusion, in which the sufferer believes he is dead and cannot be convinced otherwise.
Nothing about the brain is simple. Even being unconscious is a complicated matter. As well as being asleep, anesthetized, or concussed, you can be in a coma (eyes closed and wholly unaware), a vegetative state (eyes open but unaware), or minimally conscious (occasionally lucid but mostly confused or unaware). Locked-in syndrome is different again. It is being fully alert but paralyzed and often able to communicate only with eye blinks.
No one knows how many people are alive but minimally conscious or worse, but Nature Neuroscience suggested in 2014 that the number globally is probably in the hundreds of thousands. In 1997, Adrian Owen, then a young neuroscientist working in Cambridge, England, discovered that some people thought to be in a vegetative state are in fact fully aware but powerless to indicate the fact to anyone.
In his book Into the Gray Zone, Owen discusses the case of a patient named Amy who suffered a serious head injury in a fall and for years lay in a hospital bed. Using an fMRI scanner, and carefully watching the woman’s neural responses when researchers asked her a series of questions, they were able to determine that she was fully conscious. “She had heard every conversation, recognised every visitor, and listened intently to every decision being made on her behalf.” But she was unable to move a muscle—to open her eyes, scratch an itch, express any desire. Owen believes that something in the region of 15 to 20 percent of people thought to be in a permanent vegetative state are in fact fully aware. Even now the only certain way to tell if a brain is working is if its owner says it is.
Perhaps nothing is more unexpected about our brains than that they are much smaller today than they were ten thousand or twelve thousand years ago, and by quite a lot. The average brain has shrunk from 1,500 cubic centimeters then to 1,350 cubic centimeters now. That’s equivalent to scooping out a portion of brain about the size of a tennis ball. That’s not at all easy to explain, because it happened all over the world at the same time, as if we agreed to reduce our brains by treaty. The common presumption is that our brains have simply become more efficient and able to pack more performance into a smaller space, rather like cell phones, which have grown more sophisticated as they have contracted in size. But no one can prove that we haven’t simply grown dimmer.
Over roughly the same period, our skulls have also become thinner. No one can really explain that either. It may be simply that a less robust and active lifestyle means that we don’t need to invest in skull bone in the way we used to. But then again it may simply be that we aren’t what we once were.
And with that sobering thought to reflect upon, let’s look at the rest of the head.
*1 I am much indebted to Dr. Magnus Bordewich, director of research in the Department of Computer Science at Durham University, for some of these calculations.
*2 You have two of each, one in each hemisphere, so really they ought to be referred to in the plural (thalami, hippocampi, amygdalae, and so on), but they seldom are.
*3 Another extraordinary example of imaginary memories occurred in an experiment at an unidentified university in Canada where sixty volunteer students were confronted with the accusation that during adolescence they had committed a crime involving theft or assault for which they had been arrested. None of this had actually happened, but after three sessions with a kindly but manipulative interviewer, 70 percent of the volunteers confessed to these imaginary incidents, often adding vivid incriminating details—entirely imaginary but sincerely believed.
*4 In surely its most questionable entry, the 2001 Oxford Companion to the Body says, “For many people the term ‘lobotomy’ conjures up images of disturbed beings whose brains have been damaged or mutilated extensively, leaving them at best in a vegetative state without a personality or feelings. This was never true.” Actually, it was.
5 THE HEAD
This was not merely an idea, but a flash of inspiration. At the sight of that skull, I seemed to see all of a sudden, lighted up as a vast plain under a flaming sky, the problem of the nature of the criminal.
—CESARE LOMBROSO
WE ALL KNOW that you can’t live without your head, but how long exactly is a question that received rather a lot of attention in the late eighteenth century. It was a good time to wonder because the French Revolution gave inquiring minds a steady supply of freshly lopped heads to examine.
A decapitated head will still have some oxygenated blood in it, so loss of consciousness may not be instantaneous. Estimates of how long the brain can keep working range from two seconds to seven, and that is assuming a clean removal, which was by no means always the case. Heads don’t come off easily even with stout blows from a specially sharpened ax wielded by an expert. As Frances Larson notes in her fascinating history of decapitation, Severed, Mary, Queen of Scots, needed three hearty whacks before her head hit the basket, and hers was a comparatively delicate neck.
Many observers at executions claimed to have witnessed evidence of consciousness from newly separated heads. Charlotte Corday, guillotined in 1793 for the murder of the radical leader Jean-Paul Marat, was said to wear a look of fury and resentment when the executioner held her head up to the cheering crowd. Others, as Larson notes, were reported to have blinked or moved their lips as if trying to speak. A man named Terier was said to have turned his gaze to a speaker some fifteen minutes after being separated from his body. But how much of this was reflex, or exaggerated in the retelling, no one could say. In 1803, two German researchers decided to bring some scientific rigor to the matter. They pounced on the heads as they fell and examined them immediately for any sign of alertness, shouting, “Do you hear me?” None responded, and the investigators concluded that loss of consciousness was immediate or at least too swift to measure.
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No other part of the body has received more misguided attention, or proved more resistant to scientific understanding, than the head. The nineteenth century in particular was something of a golden age in this respect. The period saw the rise of two distinct but often confused disciplines, phrenology and craniometry. Phrenology was the practice of correlating bumps on a skull with mental powers and attributes of character, and it was always a marginal pursuit. Craniometrists virtually without exception dismissed phrenology as crackpot science while promulgating an alternative nonsense of their own. Craniometry focused on more precise and comprehensive measurements of volume, shape, and structure of the head and brain but in pursuit, it must be said, of equally preposterous conclusions.*1