Sorry, teenagers. It's not looking so good for marijuana: a new study links casual marijuana use with significant changes to parts of the brain

DEA photo of marijuana; chocolate cake might be a better option since cocoa has antioxidants and phytochemicals.

A lot of kids are going to be unhappy about this news. But there are other things to enjoy. How about some chocolate?

Casual marijuana use linked to brain changes
Karen Weintraub
USA TODAY
April 15, 2014

Using marijuana a few times a week is enough to physically alter critical brain structures, according to a new study published Tuesday in The Journal of Neuroscience.

"Just casual use appears to create changes in the brain in areas you don't want to change," said Hans Breiter, a psychiatrist and mathematician at the Northwestern University Feinberg School of Medicine in Chicago, who led the new study.

There is actually very little research on the potential benefits and downsides of casual marijuana smoking — fewer than four times a week on average.

In his study, done in collaboration with researchers at Harvard University, scientists looked at the brains of 20 relatively light marijuana users and 20 people who did not use it at all. All 40 were college students in the Boston area.

The study found volume, shape and density changes in two crucial brain areas — the nucleus accumbens and the amygdala — involved with emotion and motivation and some types of mental illness. "This is a part of the brain you do not want to mess around with," Breiter said.

The more marijuana the students smoked, the more their brains differed from the non-users, the study found.

The brain continues to develop well into the 20s, and even into the 30s, said Breiter, who is concerned about the long-term impacts of marijuana use on the developing brain.

Staci Gruber, an associate professor of psychiatry at Harvard Medical School, who was not involved in the research, said Breiter's findings are consistent with her own, although she has focused on somewhat heavier users.

"There have been a growing number of studies that suggest that marijuana use in emerging adults is associated with differences in brain structure and cognitive abilities," said Gruber, also the director of Cognitive and Clinical Neuroimaging Core at McLean Hospital outside Boston. "I'm not saying (pot smoking) is analogous to shooting heroin or cocaine, but it's also not quite the benign substance people thought it was."

Responding to a study that found a decline in IQ points among people who used marijuana regularly, Francis Collins, the director of the National Institutes of Health, told USA TODAY recently that people should be more aware of these potential brain impacts.

"Perhaps it would be better if ... there was a little bit more recognition of that particular consequence," he said.

Gregory Gerdeman, a biologist and neuropharmacologist at Eckerd College in St. Petersburg, Fla., said he has no reason to doubt the new study's findings but worries generally about marijuana research funded by federal agencies, like the Office of National Drug Control Policy, which is charged with limiting drug use. (The research was supported by grants from the National Institutes of Health as well as the Office of National Drug Control Policy and Northwestern Medicine's Warren Wright Adolescent Center.)

"If you're getting money from the drug czar's office, that money's not going to continue if you don't end up publishing something that at least supports the general story of the danger of drug abuse," Gerdeman said.

He said it doesn't surprise him that heavy pot smoking might make it difficult for students to reach their intellectual potential. But still, he said, "if it were my child, even with this study, I'm more comfortable with young people having a casual marijuana habit than drinking regularly."

Recent Studies Raise the Possibility That Male Brains Are Wired for Focus, Female Brains for Multitasking

Boys and girls brains start to differentiate in adolescence.

"Broadly speaking, women in their 20s had more connections between the two brain hemispheres while men of the same age had more connective fibers within each hemisphere. "Women are mostly better connected left-to-right and right-to-left across the two brain hemispheres," Dr. Verma said. "Men are better connected within each hemisphere and from back-to-front."

"That suggests women might be better wired for multitasking and analytical thought, which require coordination of activity in both hemispheres. Men, in turn, may be better wired for more-focused tasks that require attention to one thing a time. But the researchers cautioned such conclusions are speculative."

Differences in How Men and Women Think Are Hard-Wired
Recent Studies Raise the Possibility That Male Brains Are Wired for Focus, Female Brains for Multitasking
Robert Lee Hotz
Wall Street Journal
Dec. 9, 2013

So many things come down to connections—especially the ones in your brain.br/>
Women and men display distinctive differences in how nerve fibers connect various regions of their brains, according to a half-dozen recent studies that highlight gender variation in the brain's wiring diagram. There are trillions of these critical connections, and they are shaped by the interplay of heredity, experience and biochemistry.br/>
No one knows how gender variations in brain wiring might translate into thought and behavior—whether they might influence the way men and women generally perceive reality, process information, form judgments and behave socially—but they are sparking controversy.br/>
"It certainly is incendiary," said Paul Thompson, a professor of neurology and director of the University of Southern California's Imaging Genetics Center. He is directing an effort to assemble a database of 26,000 brain scans from 20 countries to cross-check neuroimaging findings. "People who look at findings about sex differences are excited or enraged," he said. br/>
Combined brain scans of 949 subjects, ages 8 to 22, show how neural connections differ by gender. Male brains, top, have more connections within hemispheres (blue lines). Female brains, bottom, have more between hemispheres (orange lines). Proceedings of The National Academy of Sciences/University of Pennsylvaniabr/>
Researchers are looking at the variations to explain the different ways men and women respond to health issues ranging from autism, which is more common among men, and multiple sclerosis, which is more common among women, to strokes, aging and depression. "We have to find the differences first before we can try to understand them," said Neda Jahanshad, a neurologist at USC who led the research while at the University of California, Los Angeles. br/>
Dr. Jahanshad and her UCLA collaborators conducted a 2011 brain-imaging study of healthy twins, including 147 women and 87 men, to trace connections in the brain. She discovered "significant" sex differences in areas of the brain's frontal lobe, which is associated with self-control, speech and decision-making. br/>
In the most comprehensive study so far, scientists led by biomedical analyst Ragini Verma at the University of Pennsylvania found the myriad connections between important parts of the brain developed differently in girls and boys as they grow, resulting in different patterns of brain connections among young women and young men. br/>
The team imaged the brains of 949 healthy young people, 521 females and 428 males, ranging in age from 8 to 22. Like Dr. Jahanshad's team, Dr. Verma employed a technique called Diffusion Tensor Imaging to trace how water molecules align along the brain's white-matter nerve fibers, which form the physical scaffolding of thought. The study was reported earlier this month in the journal the Proceedings of the National Academy of Sciences. br/>
Pairs of scan images show gender differences in brain wiring in childhood (1), adolescence (2) and young adulthood (3). Male brains are on left, female on right. University of Pennsylvania, Proceedings of The National Academy of Sciences.br/>
The neural patterns emerged only when combining results from hundreds of people, experts said. In any one person, gender patterns may be subsumed by the individual variations in brain shape and structure that help make every person unique.br/>
Dr. Verma's maps of neural circuitry document the brain at moments when it is in a fury of creation. Starting in infancy, the brain normally produces neurons at a rate of half a million a minute, and reaches out to make connections two million times a second. By age 5, brain size on average has grown to about 90% of adult size. By age 20, the average brain is packed with about 109,000 miles of white matter tissue fibers, according to a 2003 Danish study reported in the Journal of Comparative Neurology.br/>
Spurred by the effects of diet, experience and biochemistry, neurons and synapses are ruthlessly pruned, starting in childhood. The winnowing continues in fits and starts throughout adolescence, then picks up again in middle age. "In childhood, we did not see much difference" between male and female, Dr. Verma said. "Most of the changes we see start happening in adolescence. That is when most of the male-female differences come about."br/>
Broadly speaking, women in their 20s had more connections between the two brain hemispheres while men of the same age had more connective fibers within each hemisphere. "Women are mostly better connected left-to-right and right-to-left across the two brain hemispheres," Dr. Verma said. "Men are better connected within each hemisphere and from back-to-front."br/>
That suggests women might be better wired for multitasking and analytical thought, which require coordination of activity in both hemispheres. Men, in turn, may be better wired for more-focused tasks that require attention to one thing a time. But the researchers cautioned such conclusions are speculative.br/>
Experts also cautioned that subtle gender differences in connections can be thrown off by normal disparities in brain size between men and women and in the density of brain tissue. Other factors, such as whether one is left- or right-handed, also affect brain structure. br/>
Also affecting results are differences in how computer calculations are carried out from one lab to the next. "With neuroimaging, there are so many ways to process the data that when you do process things differently and get the same result, it is fantastic," Dr. Jahanshad said.

Why the teen brain is drawn to risk

"...[W]hile adults tend to prefer the certainty of misery to the misery of uncertainty, as family therapist Virginia Satir once put it, the same may not be true for teens."

Why the teen brain is drawn to risk
By Maia Szalavitz
TIME.com
October 8, 2012

If you're the parent of a tween, be warned: your cautious 10-year-old is bound to turn into a wild child in a few short years, with seemingly no regard whatsoever for safety. Indeed, teenagers have the double the risk of dying compared to their preteen selves.

Adults have long reckoned with ways to protect adolescents from their own misjudgments. Only recently, however, have researchers really begun to understand how the teen brain is wired and that some of what appear to be teens' senseless choices may result from biological tendencies that also prime their brains to learn and be flexible.

Take teens' perception of risk. It's certainly different from that of adults, but not in the ways you'd expect.

Research shows, for instance, that teens tend to wildly overestimate certain risks -- of things like unprotected sex and drug use -- not to lowball them as one would predict.

So, it may be that teens' notorious risk-taking behavior stems not from some immunity to known risks, but rather, as a new study now suggests, from their greater tolerance to uncertainty and ambiguity -- that is, unknown risks.

"Relative to adults, adolescents engage more in unknown risks than they do in known risks," says Agnieszka Tymula, a postdoctoral student at New York University and the lead author of the study, which was published in the Proceedings of the National Academy of Sciences.

Teens, it seems, love the unknown.

TIME.com: The half-baked teen brain: A hazard or a virtue?

To examine the differences in risk-taking between teens and adults, researchers studied 33 healthy adolescents aged 12 to 17, along with 30 normal adults aged 30 to 50. They all engaged in a gambling game, in which they could take a definite $5 reward or choose between the possibility of getting a much larger payout or nothing at all.

The payout was based on whether there was a greater number of red or blue poker chips in a stack of 100; to vary the ambiguity, larger or smaller portions of the stacks were hidden from view.

In this way, the trials provided different amounts of information about the risks involved: for example, in some trials, participants could choose between the $5 and a clear 50% chance of winning $50. In others, however, they had a choice between $5 and varying amounts of money, up to $125, but the probability of winning appeared to vary from 25% to 75%. In reality, they always had a 50% chance of winning, but were led to believe their odds varied, which allowed researchers to look at how participants thought about ambiguity.

Survey: 17% of high schoolers drink, smoke, use drugs during school day

"If the risks are known, adolescents engage (in risk-taking) less than adults do, but if they are unknown, this is reversed," Tymula says. In fact, when the payout was known to be $125, adults always gambled -- but this was not so for teens.

"I think (the finding) adds very nicely to the literature," says Valerie Reyna, professor of human development and psychology at Cornell University, who was not associated with the research. "The new breakthrough here is that it extends our knowledge about adolescent risk-taking into the realm of ambiguity aversion."

Reyna's own research has shown how excessively teens tend to overestimate risk: for example, when asked about the risk of AIDS in one study, adolescents estimated that a teenage girl who is sexually active has a 60% chance of contracting HIV. (The actual odds are miniscule for most Americans.)

This perception, however, doesn't prevent teens from engaging in risky behavior. Why? Because teens have a different style of information processing, Reyna argues. They may get lost in the details about specific risks and overly focused on possible rewards, while ignoring the overall "gist" of the problem -- i.e., the ultimate consequences.

In the case of unprotected sex, for example, even if the odds of contracting HIV are low, a bad outcome would be irreversible. Unlike teens, adults tend to focus on the end result and the consequences.

TIME.com: Teens' IQ may rise or fall over time

Oddly, teens' information-processing style seems to rely on the uniquely human "rational" parts of the brain. Reyna's work has shown that adolescents carefully think about risks most adults wouldn't even consider taking -- like, say, playing Russian roulette -- using their prefrontal cortex.

They use quantitative reasoning and take about twice as long as adults do before responding, while adults immediately have a negative reaction to such risks, stemming intuitively from the insula, and almost automatically say no.

So why might the teenage brain be wired this way? Their greater tolerance for uncertainty and the unknown -- and an increased desire for and focus on rewards -- probably helps them leave the nest.

Such explanations are speculative, Reyna cautions, but notes that "in rats, for example, adolescent rats are more likely to explore a new environment. You don't know what you're going to find: that's sort of the definition of a novel environment. If you are more ambiguity tolerant, that would enable that sort of exploration."

In other words, it takes some acceptance of uncertainty and comfort with not knowing in order to learn and to be open to new knowledge.

"We come into the world with limited knowledge about what kind of consequences we will experience after making decisions and also about how likely these different outcomes are," says Tymula. "But, of course, we want to learn, so this tolerance for unknown risks might stem from an underlying biological feature that makes learning about the unknown less unpleasant for adolescents than it is for adults."

An early part of learning any type of new skill -- from typing to teaching -- is accepting instruction and consciously thinking about all of the tactics and techniques involved in performing the skill.

While novices need to think step-by-step, however, experts will have incorporated the best routines into their brains to the point that they become automatic. This may be why the teen brain uses the higher-order cortex for risk decisions: it hasn't yet made enough of them to develop an intuitive reaction that it can "offload" to other brain regions.

Such new information about how the teen brain works -- and why its characteristics shouldn't simply be seen as negative or dysfunctional -- is only just beginning to inform teen health programs.

Reyna, for example, has studied how teaching "gist"-based reasoning can help teens avoid dangerous sexual choices, finding that teens who are taught to focus on potential, catastrophic negative outcomes, rather than the odds, make fewer risky sexual decisions and have fewer partners.

Tymula suggests that allowing teens opportunities to safely experiment -- for example, a simulator that shows sober teens what drunk driving is like -- could also help, by making an unknown risk seem more real and known. Allowing teens the opportunity to take risks in a safe context could also help them develop expertise that underlies gist-based thinking.

Meanwhile, it's interesting to note that while adults tend to prefer the certainty of misery to the misery of uncertainty, as family therapist Virginia Satir once put it, the same may not be true for teens.

TIME.com: What goes on inside the brain of a misbehaving boy?

This story was originally published on TIME.com.

Listening to Mozart seems to trigger neurons that make the brain function better--and saves lives!

This story is about making the brain work better--much better, in the case of one doctor who tripled his polyp detection rate when listening to Mozart.

Could Mozart Decrease Your Risk of Colon Cancer?
By Katie Moisse
ABC News
Oct 31, 2011

Doctors were more likely to detect precancerous polyps during colonoscopies if they had Mozart playing in the background, a small study found.

It only included two doctors, but for one, listening to Mozart more than tripled the polyp detection rate from 21.25 percent to 66.7 percent, researchers from the University of Texas Health Science Center at Houston reported today at the American College of Gastroenterology annual meeting. Undetected, the polyps — called adenomas — can become cancerous.

“Anything we can do get those rates up has the potential to save lives,” study author Dr. Catherine Noelle O’Shea said in a statement. “While this is a small study, the results highlight how thinking outside the box — in this case using Mozart — to improve adenoma detection rates can potentially prove valuable to physicians and patients.”

The polyp detection rate for the other doctor studies rose from 27.16 percent to 36.7 percent.

The study adds weight to the “Mozart effect” — the long-standing observation that listening to music can lead to a short-term improvement on some mental tasks. Some experts attribute the performance boost to a more positive mood or increased arousal. Others say complex music triggers a response in the brain that makes it better equipped to tackle an additional task...

Emerging adulthood: the only people who got this right were the car-rental companies

What Is It About 20-Somethings?
By ROBIN MARANTZ HENIG
New York Times
August 18, 2010

...Neuroscientists once thought the brain stops growing shortly after puberty, but now they know it keeps maturing well into the 20s. This new understanding comes largely from a longitudinal study of brain development sponsored by the National Institute of Mental Health, which started following nearly 5,000 children at ages 3 to 16 (the average age at enrollment was about 10). The scientists found the children’s brains were not fully mature until at least 25. “In retrospect I wouldn’t call it shocking, but it was at the time,” Jay Giedd, the director of the study, told me. “The only people who got this right were the car-rental companies.” When the N.I.M.H. study began in 1991, Giedd said he and his colleagues expected to stop when the subjects turned 16. “We figured that by 16 their bodies were pretty big physically,” he said. But every time the children returned, their brains were found still to be changing. The scientists extended the end date of the study to age 18, then 20, then 22. The subjects’ brains were still changing even then. Tellingly, the most significant changes took place in the prefrontal cortex and cerebellum, the regions involved in emotional control and higher-order cognitive function.

As the brain matures, one thing that happens is the pruning of the synapses. Synaptic pruning does not occur willy-nilly; it depends largely on how any one brain pathway is used. By cutting off unused pathways, the brain eventually settles into a structure that’s most efficient for the owner of that brain, creating well-worn grooves for the pathways that person uses most. Synaptic pruning intensifies after rapid brain-cell proliferation during childhood and again in the period that encompasses adolescence and the 20s. It is the mechanism of “use it or lose it”: the brains we have are shaped largely in response to the demands made of them. ...

We're learning when we're idling (as long as we studied hard before we took a rest)

When I was a college freshman I couldn't stay up all night, so I thought I was at a disadvantage to my fellow students who engaged in all-night cram sessions before an exam. I was puzzled as to why I scored higher than they did on the test. Now I know:

Studies: An Idle Brain May Be Ripe for Learning
By Anita Hamilton
Jan. 29, 2010
Time

Why is it so hard to remember even things we don't want to forget? The problem, suggests a growing body of research, may be that we're thinking about them too much in the first place.

Popular wisdom once held that a mind at rest was like an engine idling — not much going on under the hood. To glean insights into how the brain worked, scientists would study only volunteers in action, measuring their physiological or biochemical responses as they completed specific mental tasks. But more recently, thanks in large part to the proliferation of functional magnetic resonance imaging (fMRI), which precisely maps brain activity based on changes in blood-oxygen levels, neuroscientists have found that important activity in the brain — related in particular to memory and learning — may occur when it is at rest.

Many studies over the past decade have suggested that sleep is crucial to the consolidation of memories and learning; people who take a nap after learning a new task, for instance, remember it better than those who don't snooze. And now a small but compelling new study from the lab of New York University (NYU) cognitive neuroscientist Lila Davachi finds similar evidence that the brain at rest, even while remaining awake, is conducting meaningful activity. "Your brain is doing work for you even when you're resting," says Davachi, who just published a study in Neuron showing that certain kinds of brain activity actually increase during waking rest and are correlated with better memory consolidation. "Taking a rest may actually contribute to your success at work or school," she adds...

The purpose of the scans was to compare the relative levels of spontaneous neural activity in two key brain regions involved in memory — the hippocampus and visual cortex — during rest, both before and after the visual tasks... That suggests that the visual-learning tasks had affected the brain's seemingly random firings during rest, and perhaps that the brain was conducting memory-consolidating activity during that time...

The brain activity in those who were best at finding the hidden pattern onscreen was most strongly related...

While the NYU, Washington University and Harvard studies all used different approaches, their overall findings were remarkably similar. "The brain is trying to weave ideas together even when you don't think you are thinking of anything," notes Johns Hopkins behavioral neurologist and memory expert Dr. Barry Gordon. That's something to keep in mind the next time you catch yourself daydreaming in a meeting or idly surfing Facebook when you should be studying.

Research on Tetris shows playing video games can make your brain more efficient

Image from Mind Research Institute--This graphic shows areas of the brain that functioned more efficiently after three months of video-game practice (blue) as well as areas where the cortex became thicker (red). The left and right views show the left and right brain hemispheres.

How games change your brain
September 01, 2009
by Alan Boyle, Cosmic log MSNBC

The effects of video-game playing on your brain have been studied for a quarter-century, but the latest research reveals that there are still deep puzzles yet to be solved.

One of the earliest and most noted studies in the field was conducted back in 1992 by neuroscientist Richard Haier at the University of California at Irvine, who looked at how frequent sessions with the Tetris video game changed the players' brains. The game requires players to fit colorful puzzle pieces together at a quickening pace as they fall from the top of the screen.

Back then, Haier used brain scans to discover that some parts of the brain actually used less glucose as the players became more skilled at the game. The "Tetris effect" illustrated how video-game training could make brains work more efficiently - an idea that eventually led to a whole host of brain-training games...