10.14.2005

Dead Stars Captured by a Dying Hubble


On some nights, Astronomer Andrew Fruchter is jolted from sleep by a Prokofiev theme blaring from his cell phone. The urgent message: a massive star died at the edge of the universe—several billion years ago. Unable to fight the force of gravity, the star collapsed into a black hole, setting off a huge supernova explosion, and releasing a jet of high-energy light. And now, after traveling billions of light-years, the jet’s extraordinary blaze has been spotted by satellite telescopes. The star’s collapse was long over, but the astronomer’s work had just begun.

For four years, Fruchter and his colleagues at the Space Telescope Science Institute in Baltimore, MD, have worked to pinpoint the source of these stellar explosions, called long gamma ray bursts, or LGRBs. Packing enough energy to supply the world’s electric needs for a billion billion billion years, a LGRB in our galaxy could obliterate the planet. But Fruchter’s most recent research, soon to be published in Nature, radiates good news: LGRBs don’t occur in our kind of galaxy. Based on photographs taken by the aging Hubble telescope, his work might also give reason for its contested, expensive repair.

With photos taken by the Hubble Space Telescope between February 1997 and October 2004, Fruchter compared the luminescence of galaxies containing LGRBs to those with core collapse supernovae, the celestial phenomena that spawn LGRBs. Core collapse supernovae are gigantic explosions that occur throughout the universe when a massive star runs out of nuclear fuel. But Fruchter’s photos indicate that the select few supernovae that produce LGRBs go off in specific types of galaxies—those that are small, non-spiral, and have clumps of very bright stars rather than an even distribution. They’re “scruffy little things,” Fruchter says, “not your normal, pretty galaxies.” In other words, they’re not like ours.

But why do LGRBs occur in these particular galaxies? Fruchter says LGRB galaxies are not very chemically evolved. That is, they’re made up of mostly hydrogen gas, while other galaxies—like ours—contain life-giving elements like carbon, oxygen, and nitrogen. Fruchter speculates that in evolved galaxies, these ions interact with the stream of protons and electrons that normally encircle a star, causing the star to lose a lot of mass. What’s more, he thinks the ions create a magnetic field that keeps the star from spinning as fast as it would in a galaxy made of only hydrogen. With less mass and slower spins, this means the stars in our galaxy are less likely to form the black holes that lead to LGRBs.

Astronomers detect a LGRB using the three telescopes of the “SWIFT” deep-space satellite. First, one of the telescopes detects the gamma rays of the LGRB. Within seconds, the other two “swiftly” look for the x-rays and visible light rays of the afterglow, to determine the LGRB’s exact position. The data relays to ground computers, which then pass it on to Fruchter’s cell phone. Prokofiev blares, and as Fruchter explains, “then I have to get ground-based telescopes to go follow these things.” And finally, the Hubble can take a picture. In recent months, NASA has been debating whether to give the 15-year-old telescope and its aging parts a $700 million tune-up. Fruchter is optimistic, speculating, “If they can get the shuttle working again, I think they’ll service Hubble.” If the Hubble is put to bed, Fruchter’s research will be too. But at least he’d get a good night’s sleep.

10.09.2005

Adderall Abuse on College Campuses

Gavin balances the metal tray on his lap, completely focused at the task at hand. He grinds the three orange pills to powder—slowly, steadily—with the bottom of a heavy cocktail glass, while eight sets of eyes watch in eager anticipation. Sitting in the middle of the room, he is quite literally the center of attention—and loves it. He babbles excitedly without purpose or pause.

“Did you see that guy downstairs?”

“When are we leaving—wait, wait, where are you going?”

“Who sings this song?”

Someone tells a joke. Gavin giggles.

After about ten minutes of compulsive mincing, he uses the edge of a dollar bill to form thin, uniform lines of the white powder.

He says jokingly, “look, I’m using dirty money like a cokehead.”

But it’s not cocaine that Gavin and the eight other Brown seniors are about to snort for a late-night energy rush. It’s what many doctors refer to as “kiddy coke,” and it is sweeping the dormitories and libraries of colleges throughout the nation.

It’s called Adderall, and can be bought for as little as $3 a pill. But Gavin gets his supply for free, from his best friend Ben.

Adderall is an amphetamine, a fast-acting stimulant in the same chemical family as cocaine and the infamous crystal meth. But unlike those narcotics, Adderall’s legal.

A tablet prescription, it effectively curbs the restless tendencies of many hyperactive children. It makes it easier to function in social and educational situations, which is especially beneficial to kids who have trouble paying attention at school.

Before he started Adderall, no one ever told Ben he had a learning disorder.

“I was always a very good student, you know, always got my stuff done,” he said. “But, after I started taking the pill, I was smarter. I could read for a long time, and got really interested in what I read.”

Since the early 1960s, close to 200 studies involving more than 6,000 children have investigated the efficacy of stimulants like Adderall for the treatment of inattentive kids. And according to a 1998 review article in the Journal of the American Medical Association, the meds work: stimulants significantly reduced hyperactivity and increased focus in more than 70 percent of the children tested.

But why use a stimulant to decrease hyperactivity?

Dr. Ronald Cohen, a clinical neuroscientist who specializes in attention at Miriam hospital, said it’s because of the precise workings of the brain’s frontal lobe, the seat of our attentional processes.

“It may seem paradoxical,” he said. “But really, there’s an inhibitory system in the frontal lobes that tells you: stop, look listen. So the stimulant better activates this system, making kids less hyperactive.”

Today, Adderall is America’s most widely prescribed drug for Attention Deficit Hyperactivity Disorder (ADHD) (surpassing the better-known Ritalin in 2000).

ADHD is the most commonly diagnosed psychiatric disorder of childhood, according to the National Institute of Mental Health. The neurologically-based disability affects between three and five percent of school-age children—that’s three million kids nationwide—and it occurs three times more often in boys than in girls.

No one knows exactly what causes ADHD, but twin and cross-generational studies have shown that it does have a genetic component. In 1994, the American Psychiatric Association set specific criteria for the accurate diagnosis of ADHD, which include the persistent symptoms of inattention, hyperactivity, and impulsivity.

The diagnosis of the disability has been a controversial topic in the U.S. in the past few decades, mostly because there’s no blood chemical, no brain protein, no physical blemish of any kind that definitively marks an ADHD kid from any other squirmy elementary schooler.

Ben now believes that he was originally misdiagnosed with ADHD by a psychiatrist he saw for depression and anti-anxiety problems.

“He started asking me questions, like, ‘when you’re reading a long and boring book for school, do you put it down in the middle?’ and I’d say, ‘yeah, sometimes.’ And then suddenly I had Attention Deficit Disorder,” Ben recalled.

So Ben started taking Adderall. He now takes two orange pills, 20 mg each, as soon as he gets up in the morning. Because the drug is time-released, his body absorbs it slowly all day long. He usually feels it start to wear off by nightfall.

Since the early nineties, American doctors have diagnosed more and more cases of ADHD. According to a 2000 study from the Journal of the American Medical Association, the use of stimulants by 2- to 4-year-olds increased three-fold from 1991 to 1995.

Cohen partly attributes the increase on the pressures of modern society, where so much emphasis is placed on academic achievement.

“Parents are looking for reasons why their kid isn’t doing as well as the next-door neighbor’s kid,” he said. “There are many kids with mild attention problems, who are singled out because they are only getting B’s in school but may have the IQ potential to get A’s. So do you call it ADD?”

And because children diagnosed as toddlers often take the stimulants well into adolescence and adulthood, the number of college students who pick it up weekly at the local pharmacy is also on the rise, making the drug readily available on any college campus.

Attesting to this, the scientific journal Addiction published a study earlier this year that surveyed over 10,000 randomly-selected college students across the nation. The reports were telling: 6.9 percent of respondents admitted to non-medical use of prescription stimulants like Adderall, and at some colleges this number reached as high as 25 percent.

Why do so many college students seek out Adderall?

“They call it the ‘academic steroid,’ you know,” Ben explained. “I don’t think it’s usually recreational. It’s just a shortcut, a way for them to get by without working as hard.”

The survey also found that non-medical use was higher among males, whites, fraternity and sorority members, and students who earned the lowest grade point averages. Students abused the drug most at colleges with competitive admissions standards in the northeast.

At Brown, especially in this season of lengthy term papers and tough exams, it’s Adderall’s ability to increase focus and motivation that appeals to students under a lot of academic pressure.

Gavin, a senior English major, has used Adderall dozens of times at Brown to write long academic papers.

“You take it and half an hour later, all you want to do is write,” Gavin said. “You pretty much finish the task in front of you. It lasts for like 12 hours, so you get done whatever you need to get done.”

Because it’s a prescription given to children, many college students perceive it as harmless. But this is far from accurate. For those with ADHD, the drug’s side effects may include decreased appetite, insomnia, increased anxiety, and irritability.

“I don’t eat when I’m on Adderall,” Ben said. I can’t—it’s gross to see food, especially four or five hours into it. But then I get really hungry at night when it starts to wear off.”

And for those without ADHD, the drug can take an even harder toll. Dehydration, hot flashes, stomach pains, marked aggression and even personality changes are possible side effects, according to the National Institute of Mental Health.

What’s more, Cohen warned that users without prescriptions may have unknown pre-existing conditions that would make consuming the drug especially harmful.

Without taking a full medical history, he said, taking Adderall is like “playing Russian Roulette.”

“If someone is relatively stable they might not have a reaction to it,” he explained. “But if you give it to someone who has a predisposition toward schizophrenia or manic episodes, there’s a big risk of going over the edge.”

With the recent increased rates in U.S. Adderall prescriptions, many experts worry about the potential for abuse due to increased availability.

And worry they should. The Addiction survey of 10,000 students stated that 54 percent of undergraduates who were legally prescribed stimulants for the treatment of their ADHD had been approached to sell, trade, or give away their meds within the past year.

The same survey showed—unsurprisingly—that non-medical use of stimulants correlated highly with the use of other illegal drugs. Of those who admitted to non-medical use of stimulants, 84.6 percent also used marijuana, 51.7 percent used ecstasy, and 34.6 percent used cocaine in the past year.

The potency and dangers of Adderall’s non-medical use exponentially increase when it is snorted or injected because it enters the bloodstream directly. Snorting Adderall, like any stimulant, may cause damage to the nasal and sinus cavities, respiratory problems, irregular heartbeat, psychotic episodes, and even death by toxic shock.

Cohen explained, “Even though you’re taking the same amount of drug, more of it is getting into the blood, and quickly, so its as if you were taking a much higher dose.”

The term “kiddy coke” is an appropriate one, then, for Adderall is chemically very similar to cocaine. Both drugs block the brain’s natural dopamine receptors, elevating mood and alertness using the same mechanism as anti-depressants.

Gavin snorts it when he’s feeling sluggish before a long night of partying.

“When I snort it, he said, “it has more of an energy effect. You’re just wired and you want to talk and have a good time.”

Also like cocaine, the Adderall crash can be quite extreme.

“Coming down is the worst,” said Gavin. “You definitely can’t eat, can’t go to bed...I have to drink or smoke [pot] if I want any chance of sleeping. So you’ve got to make sure to do it only when you don’t have anything important the next day.”

With the large rise in Adderall use—both medically and recreationally—there is a growing fear of a new generation growing up addicted to these “study drugs.”

Though he takes Adderall exactly as his doctor recommends, Ben still worries about what the drug does to him.

“It’s a drug I’m addicted to now, not just something that I’m being prescribed. They tell you you’re not changing yourself, that it makes you more like your normal self, but I’m not the same person I was.”

Gavin, too, recognizes the dangers of Adderall addiction.

“There is that risk, yeah. I mean, 20 mg every three weeks is very different than Ben’s 40 [mg] a day. But I realized that in the real world I won’t able to just take an Adderall to get my work done. It won’t be as easy to get.”

Ben hopes for a time in the future when he will no longer feel Adderall dependency.

“This summer I want to switch to a new drug—Strattera—it’s not a stimulant,” Ben said. “I figure it’s a good time to get off now that I’m done with school, and yeah, I wonder what it’ll be like to get off of it. But I think it’s the right thing to do.”

If caught with non-prescribed Adderall at Brown, the administration would generally follow state mandates as if it was cocaine or marijuana.

But Brown policies on use and distribution would depend on individual situations, said Associate Dean of Campus Life Terry Addison.

“It is an illegal drug. The student would have a judicial involvement, an internal investigation,” he explained.

Addison also said that distribution of the drug is more egregious than mere consumption, and that the amount exchanged would be a factor.

“We would ask if it was it just a couple of pills or a hundred,” he said. “Were they giving it to their whole floor or just one or two of their friends?”

The punishment would be still more severe, he said, if the student was uncooperative or combative when apprehended.

Regardless of how effective or fun the prescription drug may be, students should realize that when used without a prescription, Adderall is ultimately an illicit drug like any other.

Beyond the risk of disciplinary action, there are serious and long-term physical dangers that far outweigh any short-term academic advantage or single night of energy.

So this exam season, think of your health and try a Red Bull instead.

10.02.2005

Risky Business

Imagine a woman with little financial savvy, who after saving some cash is looking for a good investment. For a safe bet with small payoffs, she could buy government bonds. But if she’s willing to lose it all for a chance at fortune, she could instead buy shares of a volatile stock. Either way, her brain must somehow evaluate her economic circumstances and take action. As Daniel Bernoulli, the Dutch physicist and mathematician who is perhaps best known for his principles of fluid dynamics, explained in a 1738 paper on economic theory: “…there is no doubt that a gain of one thousand ducats is more significant to a pauper than to a rich man, though both gain the same amount.” The woman’s choice might depend upon her job security, for instance, or the number of children she has to support, or even the number of years she has left to enjoy those potential earnings. New research in monkey brains is coming closer to decoding the brain signals that ultimately drive such decisions. In a study published in this month’s Nature Neuroscience, researchers at Duke University found patterns of neural signaling that reliably indicate the riskiness of a choice. Their findings may lead to mathematical models of human risk behaviors and a better understanding of why we sometimes make irrational and even harmful decisions.

How do researchers watch and manipulate monkey decisions? Most begin by teaching them to play a simple game on a computer screen, called a visual gambling task. Two circles appear on the screen, and the monkeys are trained to pick one of by looking directly at it. Eye tracking sensors attached to their heads tell the researchers which circle they have chosen and connect to a feeding tube that instantly pays them a fruit juice reward. Old studies have focused on the objective factors that influence their decision, like the size of the reward, because they’re much easier to measure than subjective factors like how thirsty the monkey is or how much it enjoys the thrill of taking a risk. In 2003, for instance, neuroscientist Allison N. McCoy found that when given the choice between a circle that gave a small juice reward and another that gave a large reward, monkey brain responses were stronger when they chose larger rewards. These results are perhaps not so surprising—a $20 million jackpot is, after all, more exciting than a $20 scratch card.

But little had been done on the more difficult testing of subjective factors–until now. In the new Duke study, McCoy collaborated with Michael L. Platt to tackle the question of what choice would be made if they kept constant the objective value of the reward—i.e. the amount of juice the monkey would get after many trials—but varied the riskiness of its choice. By looking at one of the circles, the “certain target,” the monkey would always get a fixed amount of fruit juice. By looking at the other “risky target,” though, it had a 50:50 chance of getting a shot of juice that was either smaller or larger than the certain target. In other words, to look at the risky target was to take a gamble.

And McCoy and Platt were able to systematically change the size of the gamble. Say the certain target paid out a 50-ml reward and--because it’s certain-- this was paid every single time the monkey looked at it. But the risky target, remember, didn’t always give the same reward. On”high-risk” trials, a monkey choosing the risky target got either a 75-ml reward or a 25-ml reward. In contrast, in “low-risk” trials, looking at the risky target reaped either a 45-ml or a 55-ml dose. In all cases, the average pay-off over many trials was the same—using these hypothetical numbers, 50-ml. So you wouldn’t expect the monkeys to prefer one option over another. But here’s the kicker: McCoy and Platt’s monkeys overwhelmingly chose the risky target. What’s more, they chose it more often on the high-risk trials.

In the next part of the study, the neuroscientists looked for patterns of neuron firing that correlated with these preferences. They inserted an electrode—a tiny needle that records the number of electrical signals produced by a single neuron-- in a long and narrow brain region spanning the top of the skull to the top of the ear, called the posterior cingulate cortex. This area was chosen for recordings because it was known from previous studies that its cells were highly responsive during the activities—seeing shapes on a screen, moving the eyes quickly, receiving a reward—involved in the visual gambling task. McCoy and Platt recorded the electrical patterns generated while the monkeys performed the visual gambling game. Not only were the neuronal firings higher when the monkeys took risks, but they also fired in a predictable code: as risk was systematically increased, so too was the firing frequency. In short, they were exquisitely sensitive to risk.

These primate results could be easily translated into human terms: monkeys prefer risk, therefore humans prefer risk. But human behavior is complex, and the temptation to assume that these findings will lead to the ability to predict human behaviors should be squelched. As Daeyeol Lee put it in a Nature commentary, “an individual might insure a car used to drive to the casino.” Moreover, even given identical circumstances, every brain has a slightly different inclination toward risk; not every casino patron becomes a pathological gambler, and not every teenager who picks up a cigarette goes on to smoke a pack a day. Like most of today’s neurological research, these results are remarkable mostly because they expose systematic and surprising patterns at a microscopic level; though the authors did hint their study may have some human application “as an important model for probing the neural processes that underlie pathological risk taking in individuals with addictions to drugs, sex, food or gambling.” As for the woman looking to invest—nothing ventured, nothing gained?