Archive for the ‘ Biology ’ Category

Hey, Wait a Minute! – Biological roots of today’s anger

David P. Barash in The Chronicle Review:

No fair! No fair!

“No fair” must rank among the loudest and most readily evoked complaints. Nor is the din of inequity limited to children. Consider the widespread anger generated by the Wall Street and AIG bailouts: Regardless of whether they were justified as national policy, those and other departures from perceived evenhandedness have a long history of rousing departures from citizen complacency, and even from civility. Ditto for outrage over executives getting outsized bonuses and golden parachutes while the rest of us are left to soldier on as best we can.

In evolutionary terms, what’s going on here?

Another way of asking that question is to turn it around. Why do we feel so violated? Lixing Sun, a professor of biology at Central Washington University, thinks we have a “fairness instinct.” And he may be right. He maintains that high on the roster of human propensities is a “Robin Hood mentality” that characterizes our species and qualifies as one of those “mental modules” that evolutionary psychologists consider part of our likely biological inheritance. If so, our fairness instinct goes far beyond the pleasure we take in romantic tales of medieval Merry Men adventuring in Sherwood Forest. Sun believes that despite the fact of our specieswide social and economic disparities—perhaps in part because of them—human beings are endowed (or burdened) with an acute sensitivity to “who is getting how much,” in particular a deft attunement to whether anyone else is getting more or less than one’s self.

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The Struggle for the (Possible) Soul of David Eagleman

Robert Jensen in Killing the Buddha:

A neuroscientist imagines life beyond the brain.

There’s a struggle inside the brain of David Eagleman for the soul of David Eagleman.

That is, there might be such a struggle if Eagleman’s brain believed that Eagleman had a soul, which he is not sure about. In fact, Eagleman’s brain is not completely sure that there is an Eagleman-beyond-Eagleman’s-brain at all—with or without a soul, whatever that term might mean.

Welcome to the world of “possibilian” neuroscientist-writer David Eagleman, to life in the space between what-is and what-if, between the facts we think we know and the fictions that illuminate what we don’t know.

Eagleman-the-scientist would love to rev up his high-tech neuroimaging machines to answer the enduring questions about the brain and the mind, the body and the soul. But Eagleman-the-writer knows that those machines aren’t going to answer those questions.

Eagleman rejects not only conventional religion but also the labels of agnostic and atheist. In their place, he has coined the term possibilian: a word to describe those who “celebrate the vastness of our ignorance, are unwilling to commit to any particular made-up story, and take pleasure in entertaining multiple hypotheses.”

Taking seriously the old saying “the absence of proof isn’t the proof of absence,” Eagleman recognizes that people who don’t believe in God (at least not in God defined as a supernatural force or entity) can never say with certainty what doesn’t exist. So, the difference between agnostic and atheist is typically a matter of attitude, and such is the case with adding possibilian to the mix. Eagleman is not trying to support or rule out any particular claim but simply suggesting that it’s healthy to imagine possibilities.

While he reports on what-is in scientific journals, Eagleman’s brain and mind run free pondering the what-ifs. In his 2009 book Sum: Forty Tales from the Afterlives, Eagleman imagines life beyond death, in a playful series of short philosophical musings: What if there were an afterlife in which we relive all our experiences but shuffled into a new order? What if in an afterlife we confront all the possible versions of ourselves that could have been? What if we experience death in stages: when the body stops functioning, when we’re buried, and the moment when your name is spoken by another for the last time? Sum offers 40 such what-ifs. The stories aren’t meant as serious proposals about what an afterlife may be. They are vehicles for Eagleman’s ruminations on the vexing philosophical questions of human life.

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Lost Sleep Is Hard to Find

Erin O’Donnell in Harvard Magazine:

it’s a time-honored practice among medical residents, cramming undergrads, and anyone else burning the candle at both ends: get very little sleep for days, maybe even pull an all-nighter, and then crash for an extra-long night of shut-eye to catch up.

Ten hours of sleep at once may indeed recharge us, and allow us to perform well for several hours after waking, according to research recently published inScience Translational Medicine. But “the brain literally keeps track of how long we’ve been asleep and awake—for weeks,” says Harvard Medical School (HMS) neurology instructor Daniel A. Cohen, M.D., lead author of the study. And that means that the bigger our aggregate sleep deficit, the faster our performance deteriorates, even after a good night’s rest.

Cohen and his coauthors monitored nine young men and women who spent three weeks on a challenging schedule: awake for 33 hours, asleep for 10—the equivalent of 5.6 hours of sleep a day. (This approximates the schedule of a medical resident, but many of us live under similar conditions; the National Sleep Foundation reports that 16 percent of Americans sleep six or fewer hours a night.) When the study participants were awake, they took a computer-based test of reaction time and sustained attention every four hours.

The researchers were surprised to discover just how much an extended rest boosted test performance. “Even though people were staying awake for almost 33 hours, when they had the opportunity to sleep for 10 hours, their performance shortly after waking was back to normal,” Cohen says. “The really interesting finding here is that there’s a short-term aspect of sleep loss that can be made up relatively quickly, within a long night.”

But the days and weeks of lost sleep eventually took their toll. The investigators knew from previous research that people awake for 24 hours straight display reaction times comparable to those of people who are legally drunk. Cohen’s new study reveals that those who pull an all-nighter on top of two or three weeks of chronic sleep loss reach that level of severe impairment faster—after just 18 hours awake.

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Left-sided Cancer: Blame your bed and TV?

R. Douglas Fields in Scientific American:

Curiously, the cancer rate is 10 percent higher in the left breast than in the right. This left-side bias holds true for both men and women and it also applies to the skin cancer melanoma. Researchers Örjan Hallberg of Hallberg Independent Research in Sweden and Ollie Johansson of The Karolinska Institute in Sweden, writing in the June issue of the journal Pathophysiology, suggest a surprising explanation that not only points to a common cause for both cancers, it may change your sleeping habits.

For unknown reasons the rates of breast cancer and melanoma have both increased steadily in the last 30 years. Exposure to the sun elevates the risk of melanoma, but the sun’s intensity has not changed in the last three decades. Stranger still, melanoma most commonly affects the hip, thighs and trunk, which are areas of the body protected from the sun. What is responsible for the left-side dominance and increasing incidence of these cancers?

An intriguing clue comes from the Far East. In Japan there is no correlation between the rates of melanoma and breast cancer as there is in the West, and there is no left-side prevalence for either disease. Moreover, the rate of breast cancer in Japan is significantly lower than in the West; only 3 percent of what is seen in Sweden, for example. The rate of prostate cancer in Japan is only 10 percent of that in the U.K. and U.S.

The researchers suggest an explanation based on differences in sleeping habits in Japan and Western countries. Previous research has shown that both men and women prefer to sleep on their right sides. The reasons for this general preference are unclear, but sleeping on the right side may reduce the weight stress on the heart, and the heartbeat is not as loud as when sleeping on the left. Still, there is no reason to suspect that people in Japan sleep in positions that are any different from those in the West. The beds in Japan, however, are different. The futons used for sleeping in Japan are mattresses placed directly on the bedroom floor, in contrast to the elevated box springs and mattress of beds used in the West. A link between bedroom furniture and cancer seems absurd, but this, the researchers conclude, is the answer.

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Sky-blue-pink. A colour never before seen?

Richard Dawkins writing for richarddawkins.net:

A recurring conundrum in philosophy is the impossibility of sharing, or describing to a blind person, the subjective sensation of colour. Is my sensation of red the same as yours? Or do you see an entirely different hue that I cannot even dream of?

Do you see the number 15 here? People with color blindness cannot

It seems impossible for me to imagine a colour that I have never seen. I don’t mean some subtle shade in a paint catalogue, intermediate between colours that I know well. I mean a completely new colour, as different from the familiar as red is from blue. Proverbially we call it sky-blue-pink, but of course it would resemble no name-able colour.

I have long argued that subjective hues are constructions manufactured in the brain as convenient internal labels for light of different wavelengths. There is no reason why your brain should use the same label for red as my brain does, just because both are labelling light of the same wavelength. I have even gone so far as to speculate that bats might hear in colour. The bat’s brain constructs a detailed picture of the world using echoes instead of light. A bat, when echolocating an insect, might use the subjective sensation that we call ‘red’ as a convenient label for the furry texture of a moth, and might use ‘blue’ as an internal label for the leathery texture of a locust. These qualia are just conveniences, to be pressed into service in the way that is most useful for the species concerned. Since the mammalian brain has the capacity to construct the qualia that we call hues, and use them as internal labels to facilitate sensory distinctions, why wouldn’t bats, as fully paid-up mammals, press into sonar service the labels that we call red and blue? By the same token, I went on, perhaps rhinoceroses smell in colour.

But always, lurking in the background is the desire to imagine a completely strange and alien colour sensation, a colour never seen. I have no hope of ever enjoying that remarkable experience, not even on an LSD trip. But yesterday I nearly hit another cyclist who shot a red light and pleaded colour-blindness as his excuse, and immediately an intriguing thought occurred to me.

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Michelangelo’s secret message in the Sistine Chapel: A juxtaposition of God and the human brain

R. Douglas Fields in Scientific American:

At the age of 17 he began dissecting corpses from the church graveyard. Between the years 1508 and 1512 he painted the ceiling of the Sistine Chapel in Rome. Michelangelo Buonarroti—known by his first name the world over as the singular artistic genius, sculptor and architect—was also an anatomist, a secret he concealed by destroying almost all of his anatomical sketches and notes. Now, 500 years after he drew them, his hidden anatomical illustrations have been found—painted on the ceiling of the Sistine Chapel, cleverly concealed from the eyes of Pope Julius II and countless religious worshipers, historians, and art lovers for centuries—inside the body of God.

This is the conclusion of Ian Suk and Rafael Tamargo, in their paper in the May 2010 issue of the scientific journalNeurosurgery. Suk and Tamargo are experts in neuroanatomy at the Johns Hopkins University School of Medicine in Baltimore, Maryland. In 1990, physician Frank Meshberger published a paper in the Journal of the American Medical Association deciphering Michelangelo’s imagery with the stunning recognition that the depiction in God Creating Adam in the central panel on the ceiling was a perfect anatomical illustration of the human brain in cross section. Meshberger speculates that Michelangelo surrounded God with a shroud representing the human brain to suggest that God was endowing Adam not only with life, but also with supreme human intelligence. Now in another panel The Separation of Light from Darkness (shown at left), Suk and Tamargo have found more. Leading up the center of God’s chest and forming his throat, the researchers have found a precise depiction of the human spinal cord and brain stem.

Is the ceiling of the Sistine Chapel a 500 year-old puzzle that is only now beginning to be solved? What was Michelangelo saying by construction the voice box of God out of the brain stem of man? Is it a sacrilege or homage?

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Can AIDS Be Cured?

Jon Cohen in Technology Review:

In an aging research building at the University of Southern California, a $14.5 million biomedical experiment is under way that until a few years ago would have made many AIDS researchers snicker at its ambition. Mice are the main research subjects (for now), and some 300 of them live in a room the size of a large walk-in closet. Signs plastered to the room’s outer door include blaze-orange international biohazard symbols and a blunter warning that says, “This Room Contains: HIV-1 Infected Animals.” Yet the hazard is accompanied by an astonishing hope. In some of the infected mice, the virus appears to have declined to such low levels that the animals need no further treatment.

This is a feat that medications have not accomplished in a single human, although daily doses of powerful anti-HIV drugs known as antiretrovirals can now control the virus and stave off AIDS for decades. Every person who stops taking the drugs sees levels of HIV skyrocket within weeks, and immune destruction follows inexorably. The lack of a cure–a way to eliminate HIV from an infected person or render it harmless–remains an intractable and perplexing problem.

“This doesn’t look like a multimillion-dollar operation at all, does it?” jokes Paula Cannon, a lead researcher on the project, as she enters the ill-smelling room, which has shelves lined with mice living together in plastic cages that resemble large shoeboxes. As she leads a tour of the cramped space, Cannon wears a face mask, a hairnet, a gown over her clothes, latex gloves, and cloth shoe coverings over her stylish heeled boots. She takes these precautions not to protect herself but to ensure that she won’t transmit a dangerous infection to this colony of mice–which is worth somewhere around $100,000.

The experiment costs so much in part because Cannon and her team had to purchase mice bred to have no immune systems of their own; the AIDS virus normallycannot copy itself in mouse cells, making ordinary mice worthless as disease models. Human immune-system stem cells are transplanted into pups bred from these mice when they are two days old, and over the next few months, those cells mature and diversify into a working immune system. Then the mice are infected with HIV, which attacks the immune cells. But before transplanting the original human cells, the researchers introduce an enzyme that interferes with the gene for a protein the virus needs to stage the attack. This modification makes a small percentage of the mature immune cells highly resistant to HIV, and because the virus kills the cells it can infect, the modified cells are the only ones that survive over time. Thus, the HIV soon runs out of targets. If this strategy works, the virus will quickly become harmless and the mice will effectively be cured.

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