The Longform Guide to the Brain

Experimental neuroscience, conjoined brains, and everlasting consciousness.

 Preserved brains are displayed at the new 'Brains' exhibition at the Wellcome Collection on March 27, 2012 in London, England.
 Preserved brains are displayed at the new ‘Brains’ exhibition at the Wellcome Collection on March 27, 2012 in London, England.

Photo by Dan Kitwood/Getty Images

Every weekend, Longform shares a collection of great stories from its archive with Slate. For daily picks of new and classic nonfiction, check out Longform or follow @longform on Twitter. Have an iPad? Download Longform’s app to read the latest picks, plus features from 70 of the world’s best magazines, including Slate.

Though many mysteries of the brain remain unsolved, advances in medicine and technology are bringing us closer to understanding exactly how it functions. Here are stories on brain breakthroughs, the scientists who made them, the patients who experienced them, and the ethics behind it all:

The Brain That Changed Everything
Luke Dittrich • Esquire • October 2010

When a neurosurgeon cut in to Henry Molaison’s brain in 1953, his life changed forever. So would everything that science ever knew about memory.

“Brain surgery is an ancient craft — there is a four-thousand-year-old hieroglyphic text describing successful operations — and among my grandfather’s most interesting artifacts was a collection of premodern and tribal neurosurgical instruments. As a kid, I found those picks and blades fascinating and terrible to contemplate. It wasn’t just the age of the tools, it was the acts they were intended for. Brain surgery, whatever the era, always requires at least two frightening qualities in its practitioners: the will to make forcible entry into another man’s skull, and the hubris to believe you can fix the problems inside.”

Could Conjoined Twins Share a Mind?
Susan Dominus • New York Times Magazine • May 2011

On the shared life of Tatiana and Krista Hogan.

“Twins joined at the head—the medical term is craniopagus—are one in 2.5 million, of which only a fraction survive. The way the girls’ brains formed beneath the surface of their fused skulls, however, makes them beyond rare: their neural anatomy is unique, at least in the annals of recorded scientific literature. Their brain images reveal what looks like an attenuated line stretching between the two organs, a piece of anatomy their neurosurgeon, Douglas Cochrane of British Columbia Children’s Hospital, has called a thalamic bridge, because he believes it links the thalamus of one girl to the thalamus of her sister. The thalamus is a kind of switchboard, a two-lobed organ that filters most sensory input and has long been thought to be essential in the neural loops that create consciousness. Because the thalamus functions as a relay station, the girls’ doctors believe it is entirely possible that the sensory input that one girl receives could somehow cross that bridge into the brain of the other. One girl drinks, another girl feels it”

The Itch
Atul Gawande • The New Yorker • June 2008

What the sensation of an uncontrollable itch can tell us about how the brain operates.

“Contemplating what it’s like to hold your finger in a flame won’t make your finger hurt. But simply writing about a tick crawling up the nape of one’s neck is enough to start my neck itching. Then my scalp. And then this one little spot along my flank where I’m beginning to wonder whether I should check to see if there might be something there. In one study, a German professor of psychosomatics gave a lecture that included, in the first half, a series of what might be called itchy slides, showing fleas, lice, people scratching, and the like, and, in the second half, more benign slides, with pictures of soft down, baby skin, bathers. Video cameras recorded the audience. Sure enough, the frequency of scratching among people in the audience increased markedly during the first half and decreased during the second. Thoughts made them itch.”

The Strange Neuroscience of Immortality
Evan R. Goldstein • The Chronicle of Higher Education • July 2012

How some scientists are turning to connectomes—maps of the brain’s neural circuitry—to make the case for brain preservation, mind uploading, and eternal life.

“Among some connectomics scholars, there is a grand theory: We are our connectomes. Our unique selves—the way we think, act. Feel—is etched into the wiring of our brains. Unlike genomes, which can never change, connectomes are forever being molded and remolded by life experience. Sebastian Seung, a professor of computational neuroscience at the Massachusetts Institute of Technology and a prominent proponent of the grand theory, describes the connectome as the place where ‘nature meets nurture.’

“Hayworth takes this theory a few steps further. He looks at the growth of connectomics—especially advances in brain preservation, tissue imaging, and computer simulations of neural networks—and sees something else: a cure for death.

The Brain on Trial
David Eagleman • Atlantic • July 2011

Should the discovery of a brain disease or disorder excuse a person from prosecution? How recent advancements in brain science are changing understandings of volition.

“As our understanding of the human brain improves, juries are increasingly challenged with these sorts of questions. When a criminal stands in front of the judge’s bench today, the legal system wants to know whether he is blameworthy. Was it his fault, or his biology’s fault?

“I submit that this is the wrong question to be asking. The choices we make are inseparably yoked to our neural circuitry, and therefore we have no meaningful way to tease the two apart. The more we learn, the more the seemingly simple concept of blameworthiness becomes complicated, and the more the foundations of our legal system are strained.”

The Split Brain: A Tale of Two Halves
David Wolman • Nature • March 2012

How a radical surgery intended to separate the right hemisphere of the brain from the left impacted both researchers and patients.

“But what Vicki could never have known was that her surgery would turn her into an accidental superstar of neuroscience. She is one of fewer than a dozen ‘split-brain’ patients, whose brains and behaviours have been subject to countless hours of experiments, hundreds of scientific papers, and references in just about every psychology textbook of the past generation. And now their numbers are dwindling.

“Through studies of this group, neuroscientists now know that the healthy brain can look like two markedly different machines, cabled together and exchanging a torrent of data. But when the primary cable is severed, information — a word, an object, a picture — presented to one hemisphere goes unnoticed in the other.”

As Good as Dead
Gary Greenberg • The New Yorker • August 2001

Is there really such a thing as brain death?

“When I spoke to Nick’s parents, they still had trouble with the notion that, to become a donor, it was not enough for their son to die with his body more or less intact. He would have to have the right kind of death, with the systems in his body shutting down in a particular order. ‘I’m so confused about this part of it,’ his mother said. ‘I don’t understand why, if his heart stops beating, they can’t put him back on a respirator.” Rick, too, was confused about the moment at which “the plug will be pulled.’ In reality, there is no moment when the plug is pulled; to keep the organs viable, the respirator is left operating—and the heart keeps beating—until the surgeon removes the organs.

“Confusion about the concept of brain death is not unusual, even among the transplant professionals, surgeons, neurologists, and bioethicists who grapple with it regularly. Brain death is confusing because it’s an artificial distinction constructed, more than thirty years ago, on a conceptual foundation that is unsound. Recently, some physicians have begun to suggest that brain-dead patients aren’t really dead at all—that the concept is just the medical profession’s way of dodging ethical questions about a practice that saves more than fifteen thousand lives a year.”

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