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NewsvineHundreds of people are walking around with literally half a brain.
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A radical procedure in which doctors remove an entire hemisphere of a person’s brain is sometimes necessary in cases of incapacitating epilepsy. A recent study reported on dozens of people who received hemispherectomies at Johns Hopkins over the last 30 years. Get this: They’re all fine.
The study describes chess champions, bowling stars and successful college students. All of the patients have lost function in the hand opposite their missing hemisphere, and have no sight in that half of their field of vision. However, most are seizure-free, and their drastic brain surgery seems to have had no effect on their learning, memory or personality. On the whole, it seems having a complete brain is pretty much optional.
I guess I should be impressed with the power and plasticity of the human brain. But it just seems sort of — I don’t know — creepy. If I only really need half my brain, what is the rest of it doing all the time? Napping? Thinking about CSI reruns? Plotting against me?
My suspicions that the brain is not to be trusted are confirmed by a litany of bizarre neurological conditions.
Anosognosia is an impressive word for a strange disease. In his book “Descartes’ Error,” neurologist Antonio Damasio describes the 1975 case of Supreme Court Justice William Douglas. A debilitating stroke left him confined to a wheelchair, paralyzed on his left side. Against medical advice, Justice Douglas checked himself out of the hospital, dismissing reports of his paralysis as “a myth,” and publicly invited reporters to go hiking with him.
Douglas, like other patients with anosognosia, was completely unaware of his injury. He went so far as to claim he was kicking 40-yard field goals with his paralyzed leg. Clearly delusional, Douglas was forced to retire from the Supreme Court.
In addition to accompanying paralysis, anosognosia can come along with blindness. Blind anosognosics spend their days bumping into walls and furniture, all the while insisting they can see just fine.
The list of neurological terrors goes on. Sufferers of Capgras syndrome believe that their friends and loved ones have been replaced by identical-looking imposters. Psychiatrist Joseph Capgras, who christened the disorder, described the case of one woman who believed not only that her husband was an imposter, but that the imposters themselves were being continually replaced! She believed her husband had been swapped out over 80 times.
Prosopagnosia, described memorably in Oliver Sacks’ “The Man Who Mistook His Wife for a Hat,” means inability to recognize faces. The titular character could recognize his family and friends by their voices, but had no idea what their faces looked like. He saw faces where none existed, and went around saluting doorknobs and patting fire hydrants on the head. In the doctor’s office, his wife was standing next to the hat rack where he’d left his hat. Mistaking her face for his hat, he tried to lift it off her neck and place it on his head.
The most horrifying thing to me about these disorders is that sufferers are so convinced that they’re right. Their brains have fooled them utterly.
Turns out your brain fools you, too. A striking example comes with so-called split-brain experiments, described by Steven Pinker in “The Blank Slate.” As a treatment for severe epilepsy, doctors can actually slice a patient’s brain in two by cutting through the corpus callosum, a structure that contains most of the connections between the brain’s left and right hemispheres.
With split-brain patients, researchers can talk to just one brain hemisphere at a time. To talk to the right hemisphere, for example, they flash a picture in only one side of the patient’s visual field. If they flash a picture of a dinosaur to the right brain only, a person cannot say what they are seeing. This is because it is the left hemisphere that controls language. Cut off from this language center, the right brain is helpless to speak about what it’s seeing. However, the patient’s right hemisphere can communicate if the patient uses his hand to pick out a toy dinosaur.
When a person’s right brain is shown a command like “WALK,” the patient obeys and begins to walk out of the testing room. But when asked why he is leaving, the patient will make up a reason, like “to get a drink of water.”
A similar experiment shows a picture of a chicken to a patient’s left hemisphere and a picture of a snowstorm to his right hemisphere. Then both hemispheres have to pick out an object to go with their picture. The left hemisphere will pick a claw (to go with the chicken) while the right hemisphere will pick a shovel (to clear the snow). Both are correct. But when the patient is asked why he made those choices, he says something like “A claw is part of a chicken, and the shovel is for cleaning out the chicken coop.”
Pinker says, “The conscious mind is a spin doctor, not the commander in chief.” The conscious mind is the great rationalizer, spouting off convincing (and false) reasons for why we do what we do. Not only split-brain patients have a BS-generator in their left brain. We all do.
My brain seems more and more sinister. Maybe those kids with the hemispherectomies are better off.