President Obama pitched a human brain research initiative on Tuesday that he likened to the Human Genome Project to map all the human DNA, and said it will not only help find cures for diseases such as Alzheimer’s and autism, but create jobs and drive economic growth.

Obama proposed $100 million in federal funding to kick start the Brain Research through Advancing Innovative Neurotechnologies or BRAIN Initiative.

“Imagine if we could reverse traumatic brain injury and PTSD for our wounded veterans coming home,” Obama said at an event unveiling the initiative at the White House.

He said federal investment in basic research had led to completely unexpected inventions, from the Internet to GPS technology. “The Apollo project that put man on the moon gave us, eventually, CAT scans,” Obama said.

He said the Human Genome Project, completed in 2003, had paid $140 for every dollar invested.

“As humans we can identify galaxies light-years away, study particles smaller than an atom but we still haven’t unlocked the mystery of the 3 pounds of matter than sits between our ears,” Obama said.

"Ideas are what power our economy. It’s what sets us apart. It’s what America has been all about," he added.

"We have been a nation of dreamers and risk-takers; people who see what nobody else sees sooner than anybody else sees it.  We do innovation better than anybody else -- and that makes our economy stronger. When we invest in the best ideas before anybody else does, our businesses and our workers can make the best products and deliver the best services before anybody else."

Obama said he’ll send the proposal to Congress next week as part of his budget request. Although Congress is working to slash the federal deficit, House Majority Leader Eric Cantor signalled an early willingness to pay for this one.

“Mapping the human brain is exactly the type of research we should be funding, by reprioritizing the $250 million we currently spend on political and social science research into expanded medical research, including the expedited mapping of the human brain. It's great science,” Cantor said in a statement.

It's not clear just what the initiative will do. Obama and collins said they'd appointed a "dream team" of experts to lay out the agenda -- they should report back before the end of the summer. They are led by neurobiologists Cori Bargmann of Rockefeller University and William Newsome of Stanford University.

Allen Institute for Brain Research

The brain's "emotion center", the amygdala, is highlighted in this 3-D representation of the human brain from the Allen Human Brain Atlas.

“Investing in biomedical research is one of the wisest choices we can make as a nation,” National Institutes of Health director Dr. Francis Collins told the gathering. “The United States has been at the forefront of one medical breakthrough after another.”

The public-private initiative, with money from groups such as the Howard Hughes Medical Institute and Microsoft co-founder Paul Allen's brain mapping project, aims to find a way to take pictures of the brain in action in real time.

The $100 million funding will come from the National Institutes of Health, the Defense Advanced Research Projects Agency and the National Science Foundation, the White House said.

“We want to understand the brain to know how we reason, how we memorize, how we learn, how we move, how our emotions work. These abilities define us, yet we hardly understand any of it," said Miyoung Chun, vice president of science programs at The Kavli Foundation, which is taking part in the initiative and which funds basic research in neuroscience and physics.

The project has some big money and some big science to build on. Allen pumped another $300 million into his institute's brain mapping initiative a year ago, and has published freely available maps of the human and mouse brains. The Howard Hughes Medical Institute built a whole research campus devoted to brain science, called Janelia Farm, in Virginia.

Arati Prabhakar, director of the Defense Advanced Research Projects Agency (DARPA) pointed to a project that allowed a quadriplegic woman to control a robot arm with her thoughts alone.

"There is nothing like a project to inspire people to go to that next level," Collins told a telephone briefing.

Not everybody is happy about a centralized, administration-led project. Michael Eisen, a biologist at the University of California at Berkeley, said earlier this year that grand projects in biology such as Project ENCODE for DNA analysis were emerging as the "greatest threat" to individual discovery-driven science.

"It's one thing to fund neuroscience, another to have a centralized 10-year project to 'solve the brain,'" Eisen wrote in a Twitter update in February.

Related:

• How researchers shaped the White House's brain-mapping initiative
• Atlas aims to solve mysteries of the human brain
• Institute unveils mouse brain map

This story was originally published on Tue Apr 2, 2013 6:00 AM EDT

University of Rochester Medical Center

Human brain cells in a mouse glow green because researchers have tagged them with a gene that looks green under fluorescent light. Mice with the human cell transplants were smarter than normal mice, the researchers report.

Researchers who transplanted human brain cells into newborn mice said the rodents grew up to be smarter than their normal littermates, learning how to associate a tone with an electric shock more quickly and finding escape hatches faster.

The experiments are aimed at making models to study human brain diseases such as Huntington’s and schizophrenia, as well as nerve diseases such as multiple sclerosis. But the team at the University of Rochester say their findings also suggest that these brain cells, called glial cells, may very well be one of the important factors that make humans different from other animals.

“Human cognitive evolution might be the product of glial evolution,” said Dr. Steven Goldman, who worked with his partner and wife Dr. Maiken Nedergaard on the study. Their findings also support the growing theory that glia cells, one of the important components of the brain’s so-called white matter, are far from being passive support cells and are in fact actively involved in brain function.

Down the road, Goldman hopes the findings might lead to procedures to transplant brain cells to treat diseases as diverse as multiple sclerosis, bipolar disease and even the brain shrinkage that causes memory loss in aging.

“There are a number of diseases that are specific to humans -- neuropsychiatric diseases, schizophrenia, bipolar disease. Animals don’t get these,” Goldman said in a telephone interview. Apes might – it’s not clear. “One of the possibilities is that neuropsychiatric disorders may have evolved with glial evolution.”

Writing in the journal Cell Stem Cell, Nedergaard and Goldman said they were trying to find ways to cure mice of multiple sclerosis, which is caused when nerve cells lose their fatty coating of myelin and stop working properly. They used immature cells called glial progenitor cells taken from aborted fetuses, infused them into the brains of newborn mice, and watched what happened.

Progenitor cells are partly along the path to from undefined to “adult” cells, and seem to have a better ability to flourish when transplanted. The human glial cells not only survived in the brains of the mice – they thrived, Goldman says.

"The human glia cells essentially took over to the point where virtually all of the glial progenitor cells and a large proportion of the astrocytes in the mice were of human origin, and essentially developed and behaved as they would have in a person's brain," said Goldman.

Human glia are far more complex than mouse glia, and they help form many, many more connections, called synapses, between neurons. The more synapses, the faster and better the brain works. Tests in lab dishes showed the mouse brains with human cells transmitted signals much more quickly than normal mouse brains.

“So here we have these brains where most of the glia are human. And we know that human glia are different from those of most of other species,” Goldman says. “Have their cognitive abilities been enhanced?”

They put the animals to the test -- first a simple one called a conditioned fear response. “You expose the animals to a tone and a very mild shock,” Goldman said. “Mice don’t like to get shocked and they learn to associate the tone with the shock. Mice, when they are afraid, they freeze.” The mice with the human glia froze faster and stayed frozen longer than thieir littermates without human glia, Goldman and Nedergaard found.

“It is a really dramatic effect,” Goldman said. Some learned after just one shock to fear the tone.

Another test involved learning to find and use an escape hatch. Again, the mice with human glial cells learned faster.

To make sure it wasn’t just the transplant of fresh cells that was improving learning, the researchers transplanted mouse progenitor glial cells into newborn mice. These animals did not learn any faster.

Goldman isn’t worried that he is somehow making mice with human brains. “We are not humanizing the mice,” he says. “We were affecting the brain activity with human glial cells ... These are still mouse brains, bottom line.” Transplanting neurons might be a different matter, he said.

There are many animals that carry human cells -- from the millions of lab mice injected with human tumor cells to study cancer, to sheep engineered to produce human liver cells. But the experiment raises a red flg, says bioethicist Arthur Caplan of New York University medical center.

"This experiment is the ethical equivalent of Superstorm Sandy," Caplan says. "It brings together a controversial source of stem cells -- obtained from aborted fetuses to create human-animal chimeras which frighten many members of the public and Congress.  The utility of the work for understanding diseases and the development of therapies for them is enormous but it is vitally important that an agreed upon, transparent and enforced set of rules and review processes be instituted to govern further research using stem cells from humans in animal brains or vice versa."

These new mice might be used to study ways to treat a range of human diseases. The technique of transplanting progenitor cells into newborns might hold special promise in treating genetic diseases such as Niemann-Pick or Tay-Sachs disease, Goldman says.

These diseases both are marked by abnormal brain cells, including glia. “It is possible that by introducing normal glial cells in these kids we may well be able to treat these disorders with cell transplants,” he said.  

The technique is most definitely not a way to make people smarter, he said. But it could restore some of the normal damage caused in aging. Some cases of vascular dementia are in fact not caused by little strokes in the brain, but are age-related white matter loss, Goldman asserts. “As we get older we lose more and more white matter,” he said.

It’s possible glial cell transplants could help. But transplants of brain cells into adult mice don’t work as well. The cells take up residence but they don’t multiply and take over the way they do in the newborns, whose brains are still developing, Goldman said.

Last month, Goldman and Nedergaard reported they made human glial progenitor cells out of ordinary human skin cells that had been reprogrammed so they acted like embryonic stem cells. These so-called induced pluripotent stem cells – iPS cells for short – might one day be used as grow-your-own transplants, made using a patient’s own cells. They’d be a perfect genetic match.

The science isn’t quite there yet but researchers hope iPS cells, which are made without creating a human embryo, would be a more ethically acceptable alternative to human embryonic stem cells. That would be the route to making brain cells to treat human adults, Goldman said.

Related links:

• Baby monkeys have a mixture of cells
• Whole mice made from skin cells
• Corpses produce stem cells

Raji Cyrus/UCLA

A profile MRI of the brain with color shaded areas corresponding to areas of increased gray matter volume in active people. The blue crosshairs point to increased volume in the hippocampus with more calories burned per week. The hippocampus is the key memory and learning center of the brain.

Seniors who fit in the most daily physical activity – from raking leaves to dancing – can have more gray matter in important brain regions, researchers reported on Monday.

The scientists have images that show people who were the most active had 5 percent more gray matter than people who were the least active. Having more little gray brain cells translates into a lower risk of Alzheimer’s disease, other studies have shown.

“People really want to know what they can do to reduce their risk of Alzheimer’s disease,” said Dr. Cyrus Raji of the University of California in Los Angeles, who presented his team’s findings to a meeting of the Radiological Society of North America.

“This shows it is easier than you think.”

Raji’s team looked at the records of 876 adults, who were recruited into a larger study on heart health starting in 1989. They all got magnetic resonance imaging (MRI) brain scans in 1998 and 1999, when they were on average 78 years old, and filled out detailed questionnaires on exercise and other types of activity.

Most of them were a little overweight – with a body mass index or BMI of 27. People with BMIs above 25 are considered overweight and at 30 they are considered clinically obese.

The researchers found a huge difference in the amount of activity people reported. They were asked about everything from cycling to yard work, dancing and bicycle riding.

“The most active burned 3,434 calories per week (an extra 500 calories per day on average) compared to those in the bottom percentile who only burned 348 calories per week [through activities],” Raji said. “The most active had 5 percent more gray matter volume than the least active. That's a big number when you think about the tremendous biological forces that have to be at work for brain volume to change at all.”

And the MRIs showed the differences were in areas of the brain like the hippocampus, which is heavily damaged in Alzheimer’s disease.

“By strengthening this area, an active lifestyle can reduce risk for Alzheimer's,” Raji said. "Virtually all of the physical activities examined in this study are some variation of aerobic physical activity, which we know from other work can improve cerebral blood flow and strengthen neuronal connections.”

Money is limited for new medical research, so the UCLA team went through the records from another study -- that explains why some of the data is old. "This is the largest study of its kind that has ever been done," Raji said.

But even older data can be a gold mine for researchers. To log exercise, the volunteers wrote down all the activities they could remember over a two-week period. Some went back and filled out questionnaires five years later, so Raji's team could make some comparisons.

"We found that individuals who increased calories burned over five years also had more gray matter volume," Raji said.

Raji isn't sure how some people only managed to burn off 348 extra calories a week, but said they may have been ill or even bedridden.

When they looked in more detail at the surveys, the researchers noted that it was the people who managed to work exercise into their daily lives who racked up the most weekly calories. So unless people enjoy standard “exercise” such as running, they should find something they like and are likely to stick to, said Raji.

“No pharmaceutical drug on the market has been shown to have these effects on the brain -- not a single drug,” said Raji. And exercise is available to anyone. “And it doesn’t cost anything,” he said.

In the first 10 years of the study, 97 people developed Alzheimer’s, and just about a quarter of them were in the top 25 percent of exercisers. Raji said the disease was detected very early in this study because the volunteers were being studied so intensely. “Most had not yet been diagnosed by their primary care physicians,” he said.

Now the team is going to go through the surveys to see if the people who had the most gray matter were the least likely to develop Alzheimer’s – or if the brain disease progressed more slowly in those with the most gray matter. And they want to follow up with as many of the volunteers as possible to see how they have fared.

“I really do believe that we have strong evidence that physical activity can be a way to reduce the risk of Alzheimer’s disease,” Raji said.

How many calories can you burn doing various activities? The Centers for Disease Control and Prevention has a calculator here. An hour of dancing can burn 330 calories an hour while walking burns about 280 calories an hour.

• Related stories:
• Daily activity lowers Alzheimer's risk
• Why working out makes you live longer
• All that stress is shrinking your brain

Scientists have long assumed that fading memories are just a normal part of aging. But a new study suggests that certain 80-somethings can remember every bit as well as people much younger.

Researchers from Northwestern University found that these mentally sharp octogenarians, dubbed SuperAgers, also have brains that look very much like those of people in middle-age, according to the study published in the Journal of International Neuropsychological Society.

For the new study, researchers used MRIs to look at the thickness of the outer layer of the brain, a region called the cortex, in SuperAgers, normally aging 80-somethings, and healthy 50- to 65-year-olds.

What they found was intriguing – the SuperAgers had brains that looked very much like those of the younger people in the study and in some ways looked even healthier. 

"We were very surprised at that," says study co-author Emily Rogalski, an assistant research professor at the cognitive neurology and Alzheimer's disease center at the Northwestern University Feinberg School of Medicine

"When we looked at cortical thickness, we were very shocked to see that even with a 20- to 30-year age gap, there was seemingly no difference in the cortical thickness," she says. "In normally aging 80-year-olds, you see quite a bit of cortical thinning, even among those who are still performing normally for their age."

The cortex is key since it's involved in memory, attention, and complex thinking, also known as executive function.

Rogalski and her colleagues tested the memories and cognitive skills of 12 Chicago-area SuperAgers and 14 middle-aged volunteers. They then scanned all 26 with a 3D MRI machine and compared both groups of scans to images from normally aging 80-somethings that came from a national data bank.

Finding a group of SuperAgers was no easy task, however.

While plenty of 80-somethings showed up at the lab saying their memories were great, most didn’t remember as well as healthy middle-aged people do.

"We weren't even sure if we would be able to find any SuperAgers since we set the bar so high," says Rogalski. "They had to be as good as 50- to 65-year olds. We screened 300 people who thought they had good memories and found 30 SuperAgers."

And the MRIs showed why the 30 SuperAgers were so mentally sharp.

Rogalski found the SuperAgers' cortexes were as thick as those in people 20 to 30 years younger.

Experts believe that shrinking cortexes are a sign that cells are shriveling and dying with age - sometimes killed off by the same abnormal proteins as you see in Alzheimer's brains. One finding that really surprised Rogalski and her colleagues: a region deep in the brain, called the anterior cingulate was actually larger in SuperAgers than it was in middle-aged folks.

The anterior cingulate is very important for attention. Studies have shown that one of the reasons memory fails as we age is that we can't focus as well as we did when we were younger.

"If I were to tell you ten things you need to pick up at the grocery store and then the phone rang and you got distracted talking to your best friend you'd probably find it hard to remember those ten things when you got to the store," Rogalski explains. "That wouldn't mean your memory was bad, but rather, that you weren't able to focus on the task."

Rogalski hopes the new research on SuperAgers may help scientists unlock the secrets of these "youthful brains" and find ways to protect us against from age-related damage.

"This is the first step in a new way of looking at this - a road less traveled in aging research," she says. "Instead of looking at what is going wrong with the brain, we want to know what is going right."

As for why some people are SuperAgers and some aren't, the research team can't provide any answers at this point. It could be all related to genetics or a combination of genes and the environment: no clues popped up during the SuperAger's interviews that set them apart from people who had aged normally.

But the question of whether there's something we can do to keep mentally sharp is something Rogalski is hoping she'll be able to answer as she continues to study the SuperAger phenomenon.

Related: 

• Seniors say they sleep better than young adults
• Real 'Benjamin Button'? Stem cells reverse aging in mice

Why aren’t hoarders bothered by piles of old newspapers and the other junk that clogs their homes?

Scientists may have uncovered an important clue that could help explain why hoarders can live surrounded by mounds of clutter: A brain network that helps us decide whether something should be kept or thrown away may be malfunctioning.

The network appears to go into overload any time a hoarder tries to decide if an object is important, researchers reported in a study published in the Journal of the American Medical Association. At other times, the affected region of the brain goes too quiet, which may explain why they aren’t bothered by those old newspapers piles.

“When you go into a house like that you’ve got to start thinking, ‘How can this person live this way?’” said the study’s lead author, psychologist David Tolin, director of the Anxiety Disorders Center at The Institute of Living in Hartford, Conn. “It can be maddening if you don’t have this problem. But [hoarders] don’t really seem to recognize or appreciate it. The part of the brain that should be saying this is important is underactive.”

Tolin, an adjunct associate professor of psychiatry at the Yale University School of Medicine, and his colleagues compared brain scans from 43 hoarders to those from 31 patients with obsessive-compulsive disorder and 33 healthy volunteers. Before any of the volunteers came in, they were asked to sweep all the papers from a countertop at home into a plastic garbage bag.

“[Participants] were told we wouldn’t throw anything away that they wanted to keep,” Tolin said. Tolin and his colleagues also brought in junk mail from their homes to use as a control. The papers were put into boxes labeled either “My Stuff” or “Your Stuff.”

While in a brain scanner, study volunteers then watched a video screen as a researcher plucked a piece of paper from one of the two boxes and asked if it should be tossed into a shredder.

When hoarders were looking at someone else’s junk, there was very little activity in the brain network that includes the insula and the anterior cingulated cortex. But when they were asked about their own junk, the network sparked wildly.

“These two regions are commonly thought to constitute a network involved with the understanding of the relative importance or significance of something,” Tolin said. “When hoarding participants were not making a decision that was personally relevant it was underactive. That may explain how a person can live in a horrible environment and not seem to care about it. The flip side is that when there’s a personally relevant decision in front of them, such as whether to discard something they own, the region gets hyperactive and they are overwhelmed.”

Tolin suspects that the network hyperactivity sparks an unpleasant sensation, so hoarders just skip making any decisions to avoid the feeling.

It’s not clear whether people are born with this kind of faulty wiring or whether they simply have a predisposition that gets kicked off with the right environmental factors.

Still, Tolin said, the new research may help clinicians come up with better therapies and also explain why certain treatments, like cognitive behavioral therapy seem to work.

The idea behind those treatments is to try to get the brain to rewire through positive experiences. So, Tolin said, a therapist might coach a hoarder going through a pile of papers in the living room by asking the kinds of questions that come naturally to others: Is this something I’ve used in the last six months? If I didn’t have this would I be worse off? Is this of good enough quality that it’s worth keeping?

“Part of what we’re doing is teaching and drilling them on appropriate decision making,” Tolin said. “They’re used to responding to the overwhelming impact of these brain regions. When they start practicing doing it this way, they are actually teaching their brains not to have that reaction.”

Related:

• Elvis impersonator showcases his Garbageland on "Hoarding: Buried Alive" 
• "Facebook depression" disputed by experts
• Anxiety cranks up activity in women's brains

Watching pornography would seem to be a vision-intensive task. But new research finds that looking at erotic movies can actually quiet the part of the brain that processes visual stimuli.

Most of the time, watching movies or conducting any other visual task sends extra blood flow to this brain region. Not so when the movies are explicit, the researchers found. Instead, the brain seems to shunt blood — and therefore energy — elsewhere, perhaps to regions of the brain responsible for sexual arousal.

Turns out, the brain may not need to take in all the visual details of a sex scene, said study researcher Gert Holstege, a uroneurologist at the University of Groningen Medical Center in the Netherlands.

"If you look, for example, at your computer and you have to write something or whatever, then you have to look specifically and carefully at what you're doing because if you don't, it means you make mistakes," Holstege told LiveScience. "But the moment you are watching explicit sexual movies, that's not necessary, because you know exactly what's going on. It's not important that the door is green or yellow."

Anxiety vs. arousal
The brain can either be anxious or aroused (or neither), Holstege said, but not both. During orgasm, he has found, activity in brain regions associated with anxiety plummets. This phenomenon may explain why women with low levels of sexual desire often have high levels of anxiety, Holstege said. It makes sense; if you're looking around, focusing on visual details, scanning for danger, it may not be so easy to focus on arousal, he said.

The Sex Quiz: Myths, Taboos and Bizarre Facts

"If you yourself are in a very dangerous situation, whatever the reason, you don't have sexual feelings, because you have to survive for yourself, not survive for the species," Holstege said.

Brain-scan research had previously turned up hints that explicit sexual images might quiet a brain area called Brodmann's area 17, also called the primary visual cortex, a region that does the first processing of incoming visual information in the brain. The data was spotty, however, and no one had looked into the question in women's brains.

As part of a broader series of brain-scanning studies, Holstege examined the primary visual cortexes of 12 healthy heterosexual premenopausal women. All of the women were on hormonal birth control, smoothing out any menstrual-cycle related changes in sexual desire or arousal.

Each woman watched three videos while having her brain imaged by positron emission tomography, better known as a PET scan. These scans detect minute changes in radioactivity in the brain that correspond to the amount of blood flowing to any given region. Regions with more blood flowing to them are considered more active.

One of the videos used in the study was a simple nature documentary about marine life in the Caribbean. The other two were selections from "women-friendly" pornographic movies, one depicting only foreplay and manual stimulation and the other depicting oral sex and vaginal intercourse. Earlier studies had shown that the higher-intensity video showing intercourse produced stronger physical arousal in women than the foreplay-focused movie clip.

6 Great Things Sex Can Do For You

Safe sex
The scan results revealed that the high-intensity erotic video — and only the high-intensity erotic video — resulted in far less blood being sent to the primary visual cortex. The region is still active, just much less so. Usually, that effect is only seen when people are asked to conduct a nonvisual task, like remembering words, while also watching some sort of visual stimuli.

To Holstege, those results suggest that the brain is focusing on sexual arousal as more important than visual processing during these erotic films.

"You have to realize that the brain wants to spare as much energy as possible, so if some part of the brain is not necessary at a high level of functioning, it immediately goes down," Holstege said.

The findings have implications for sexual dysfunction, Holstege said, as they paint a picture of the brain in which safety is paramount and anxiety is a libido-killer.

"If you want to have sex, as a man, you need to produce a safe situation for the woman," Holstege said. "That is what you want, that is the most important thing."

Holstege reported his results online April 10 in the Journal of Sexual Medicine.

• 10 Surprising Sex Statistics
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• Busted! 6 Gender Myths in the Bedroom & Beyond

Everyone knows stress can cause headaches and sleepless nights. But a new study suggests it can actually shrink your brain.

We’re not talking run-of-the-mill stressors here, like a looming deadline or a missed bus.

“These are bad things happening, like a relationship breakup, loss of a loved one, being held at gunpoint,” says Yale neurobiologist Rajita Sinha, senior author of the new report.

Simply feeling stressed-out was not linked to gray matter shrinkage. But feeling stressed-out combined with a history of stressful life events was.  In particular, stress was linked to markedly less gray matter than expected in a part of the prefrontal cortex that regulates emotion and self-control, not to mention blood pressure and blood sugar.

That shrinkage might serve as a red flag about a greater risk of chronic diseases such as high blood pressure as well as psychiatric disorders, according to the researchers. And maybe it’s already affecting brain function in the healthy individuals she studied, Sinha says.

In other words, the stresses of modern life are far more complicated than what our ancestors experienced. “You can say stresses are a part of life, so what’s the big deal?” Sinha says. But it is a big deal, she adds, because there’s extensive evidence that stress has contributed to the rise in chronic diseases.

Most human research about the impact of stress on brain structure has focused on patients with stress-related psychiatric disorders such as addiction and anxiety, according to the authors. Those studies have found decreased volume in the frontal lobe, considered the center of emotion control and personality.

But studies of the cumulative effects of stress on the brains of healthy people are rare, Sinha’s team writes in a paper published online this week in Biological Psychiatry.

The study enrolled 103 health adults ages 18 to 48. Researchers conducted structured interviews with the volunteers to collect information about stressful life events and subjective feelings of chronic stress.

The scientists then used MRI to scan the volunteers’ brains.

Whose brains shrunk more, men’s or women’s? You might think you know the answer, but the researchers don’t, because they didn’t have enough women to compare the sexes.

The take-home message, Sinha says, is that the better you cope with stress -- take a walk, call a friend -- the better off your brain will be.

More like this:

Men and women really do have big personality differences

There are two types of people in the world: those who remember everything exactly as it happened and those who have a tendency to muddle what’s happened with what’s imagined.

The difference between the two may be explained by a subtle variation in the brain's structure, according to a study published in the Journal of Neuroscience.

About 50 percent of people are born with a prominent fold in the brain matter that lies just behind the forehead, explained study co-author author Jon Simons, a researcher at the University of Cambridge in the UK. Simons and his colleagues found that these are the people who seem record very accurate versions of what has happened to and around them.

In contrast, people with a less pronounced fold, or a non-existent one, seem to have problems distinguishing between what they actually experienced and what they might have imagined or heard about, Simons said.

Scientists long ago mapped out the hills and valleys of the brain. One puzzling part of that cranial geography is the significance of a missing fold in the outer part of the brain, or cortex. That fold is one of the last structures to develop in a growing fetus, Simons explained.

Simons and his colleagues suspected that this fold might somehow be involved in cataloguing memories as either real or imagined. So they designed an experiment that would distinguish between people with exacting and muddled memories.

The first step was to pore through thousands of brain scans from normal healthy people, looking for ones that showed either a prominent fold, or ones in which the fold was missing in either the right or left hemisphere.

The researchers chose 53 study volunteers, which were almost equally divided between ones with a prominent fold, ones with some folding in the left hemisphere, ones with some folding in the right hemisphere and the rest with no fold whatsoever. Because the brain fold straddles the central area of the brain, some folding may be on the left and some on the right, or both.

All 53 were shown words on the screen that often come as well-recognized pairings, such as bacon and eggs, Laurel and Hardy, Abbott and Costello. Sometimes both words were shown. Sometimes one word from a pair was shown, followed by a question mark. Then the study volunteers either heard the word pairs read by a researcher or were asked to read the words themselves aloud.

Later on, the volunteers were asked whether they actually saw both words on the screen or just one word with a question mark. They were also asked whether they read the words aloud themselves or heard someone reading the words to them. When the researchers scored the memory test they found the volunteers with no fold scored the worst, while those with prominent folds scored the best.

The new research is very intriguing, said Paul Thompson, a professor of neurology at the University of California, Los Angeles. Scientists have long known about this variation, but no one really knew what its consequences were.

Ultimately, Thompson said, the study might offer some insight into diseases like schizophrenia, in which people have trouble distinguishing between what is real and what is a hallucination.

It might also have an impact on how judges and juries perceive eye-witness testimony, Simons said. You could imagine that people without the fold “might witness a crime and then talk to someone else,” he explained. “Or they might read a newspaper report about the crime and then misremember what they actually saw.”

The tricky thing about this kind of memory issue is that people generally don’t recognize they have it, Simon said. They think their memories are every bit as accurate as everyone else’s.

Perhaps one day some enterprising defense lawyer will ask for brain scans of prosecution witnesses to see if they have accurate memories.