Archives for June 2005

In 1955, he had conducted a routine autopsy of Einstein after the 76-year-old physicist died at Princeton Hospital. The remains were to be cremated. Harvey, however, decided to preserve the organ responsible for the theory of relativity and the principle of the atomic bomb.

It was not such an unusual thing to do. Einstein’s ophthalmologist had removed the scientist’s eyeballs and put them in a safe-deposit box. Earlier acquisitive anatomists had preserved Galileo’s finger, Haydn’s head and Napoleon’s penis.

For Harvey, however, more than morbid curiosity was at work. He believed that the slippery worms of Einstein’s brain tissue, pickled in warm formalin, embodied some clue to the mystery of intelligence. He held on to that hope through 40 years of indecision.

Eventually, it led the soft-spoken Quaker to Witelson, a raven-haired Canadian psychologist with a taste for black leather and red showgirl nails.

She had brains, dozens of them — the largest collection of normal brains in the world.”

Inside her walk-in refrigerator at McMaster University here in Ontario, her collection filled three walls of metal shelves. The 125 putty-colored specimens sat in frosted jars and snap-top plastic tubs like quarts of boiled shrimp and wedges of cheese.

Every one posed a riddle that had shaped her research for 30 years: How does the structure of the brain influence intelligence?

A professor of psychiatry and neuroscience, Witelson grappled with such a fundamental mystery by studying a somewhat smaller one: why certain abilities develop on one side of the brain rather than the other.

The two hemispheres of the brain are almost symmetrical physically but can seem to be separate minds when it comes to awareness and mental processing. They even have different problem-solving styles, researchers report. Yet they work together seamlessly to produce a single mind.

By 1977, Witelson was trying to learn why language skills developed on the left side of the brain for all right-handers but on the right side for many left-handers.

To compare the two sides, she needed normal brains — more than anyone had gathered before.

For 10 years, she worked through a network of doctors and nurses, hoping to persuade terminal cancer patients to make a last contribution to medicine. Her research was funded by the U.S. National Institutes of Health.

By 1987, 120 men and women had agreed to donate their brains after death. They all submitted to thorough psychological and intelligence tests so that each brain would be accompanied by a detailed profile of the mind that had animated it.”

Her findings — published in Science, the New England Journal of Medicine, the Lancet and other peer-reviewed journals — buttress the proposition that basic mental differences between men and women stem in part from physical differences in the brain.

Witelson is convinced that gender shapes the anatomy of male and female brains in separate but equal ways beginning at birth.

On average, she said, the brains of women and men are neither better nor worse, but they are measurably different.

Men’s brains, for instance, are typically bigger — but on the whole, no smarter.

“What is astonishing to me,” Witelson said, “is that it is so obvious that there are sex differences in the brain and these are likely to be translated into some cognitive differences, because the brain helps us think and feel and move and act.

“Yet there is a large segment of the population that wants to pretend this is not true.”

But even at this relatively early stage in exploration of the brain’s microanatomy, battle lines between scientists, equal rights activists and educators have formed.
Some activists fear that research like Witelson’s could be used to justify discrimination based on gender differences, just as ill-conceived notions of human genetics once influenced laws codifying racial stereotypes about blacks, Asians and Jews.

Other experts argue that the physical differences Witelson observed may result not from the brain’s basic design but from conditioning that begins in infancy, when the brain produces neurons at a rate of half a million a minute and reaches out to make connections 2 million times a second.

Spurred by learning, neurons and synapses are ruthlessly pruned, a process that continues in fits and starts throughout adolescence, then picks up again in middle age.

“The brain is being sculpted gradually through sets of interactions,” said Anne Fausto-Sterling, a gender studies expert at Brown University. “Even when something in the brain appears biological, it may have come to be that way because of how the body has experienced the world.”

As Witelson’s research helped establish, however, the mental divide between the sexes is more complex and more rooted in the fundamental biology of the brain than many scientists once suspected.

In the last decade, studies of perception, cognition, memory and neural function have found apparent gender differences that often buck conventional prejudices.

Women’s brains, for instance, seem to be faster and more efficient than men’s.

All in all, men appear to have more gray matter, made up of active neurons, and women more of the white matter responsible for communication between different areas of the brain.

Overall, women’s brains seem to be more complexly corrugated, suggesting that more complicated neural structures lie within, researchers at UCLA found in August.

Men and women appear to use different parts of the brain to encode memories, sense emotions, recognize faces, solve certain problems and make decisions. Indeed, when men and women of similar intelligence and aptitude perform equally well, their brains appear to go about it differently, as if nature had separate blueprints, researchers at UC Irvine reported this year.

“If you find that men and women have fundamentally different brain architectures while still accomplishing the same things,” said neuroscientist Richard Haier, who conducted the study, “this challenges the assumption that all human brains are fundamentally the same.”

Yet, for the most part, scientists have been unable to document such patterns conclusively.

No one, however, had scrutinized as many brains as Witelson.

Detailing Differences

She began by studying the corpus callosum, the cable of nerves that channels all communication and cooperation between the brain’s two hemispheres.

Examining tissue samples through a microscope, she discovered that the more left-handed a person was, the bigger the corpus callosum.

To her surprise, however, she found that this held true only for men. Among women there was no difference between right-handers and left-handers.

“Once you find this one difference,” she remembered thinking, “it implies that there will be a cascade of differences.”

He had the fragile organ infused with fixative and dissected it into 240 pieces, each containing about two teaspoons of cerebral tissue. He shaved off 1,000 hair-thin slivers to be mounted on microscope slides for study.

For years, Harvey agonized over how next to proceed. His odd pursuit inspired two books: “Possessing Genius” by Carolyn Abraham and “Driving Mr. Albert” by Michael Paterniti. Through the decades, however, he drifted in obscurity.

Finally in 1985, pioneering neuroanatomist Marion Diamond at UC Berkeley persuaded him to part with four small plugs of brain tissue. Diamond discovered that the physicist’s brain had more cells servicing, supporting and nurturing each neuron than did 11 other brains she studied. These unusual cells were in a region associated with mathematical and language skills.

When they published their findings, the researchers speculated that these neurons might help explain Einstein’s “unusual conceptual powers.”

Critics contended the study was riddled with flaws, its findings meaningless.

Eventually, Harvey mailed bits of Einstein’s motor cortex to a researcher at the University of Alabama, who reported that the cortex appeared to be thinner than normal but with more tightly packed neurons.

Had it simply been compacted by time and storage conditions?

DNA testing revealed nothing. The preservative fluids apparently had scrambled Einstein’s genetic code.”

She found that one portion of Einstein’s brain perhaps related to mathematical reasoning — the inferior parietal region — was 15% wider than normal.

Witelson also found that it lacked a fissure that normally runs along the length of the brain. The average human brain has two distinct parietal lobe compartments; Einstein’s had one.

Perhaps the synapses in this area were more densely interconnected.

“Maybe this was one of the underlying factors in his brilliance,” she said. “Maybe that is how it works.”

She took it as confirmation of her suspicions about the anatomy of intelligence. If there were differences affecting normal mental ability, they would show up in the arrangements of synapses at particular points in the brain.

Einstein, she was convinced, had been born with a one-in-a-billion brain.

“We suggest that the differences we see are present at birth,” Witelson said. “It is not a consequence of environmental differences.”

She turned again to the brains in her refrigerator. Wherever she looked, she began to see evidence of how microanatomy might underlie variations in mental abilities.

As she matched the brain specimens to the intellectual qualities of their owners, she discovered that differences in the size of the corpus callosum were linked to IQ scores for verbal ability, but only in women. She found that memory was linked to how tightly neurons were packed, but only in men.

Witelson determined that brain volume decreased with age among men, but hardly at all among women. Moreover, those anatomical changes appeared to be closely tied to a gradual decline in mental performance in men. “There is something going on in the male brain,” she said, “that is not going on in the female brain.”

“This was the first time a player took on a persona in the game. Instead of controlling inanimate objects like tanks, paddles and missile bases, players now controlled a ‘living’ creature,” says Leonard Herman, author of “Phoenix: The Rise and Fall of Videogames.” “It was something that people could identify, like a hero.”

It all began in Japan, when Toru Iwatani, a young designer at Namco, caught inspiration from a pizza that was missing a slice. Puck-Man, as it was originally called, was born. Because of obvious similarities to a certain four-letter profanity, “Puck” became “Pac” when it debuted in the U.S. in 1980.”

As part of a final project for a class in New York University’s Interactive Telecommunications graduate program last year, students with cell phones and Wi-Fi Internet connections mimicked the game, tracking their movements on a grid spanning several city blocks.

They called this analog re-enactment, where four people dressed as ghosts searched for Pac-Man on the streets around New York’s Washington Square Park, Pac-Manhattan.

“We never had anyone clear the entire board,” said Frank Lantz, a game designer who taught the course.”