If you've ever burst out laughing at a funeral -- or burst into tears at a board meeting -- you can sympathize with those who suffer from pseudobulbar effect, a neurologic condition that causes involuntary laughing or crying. We wrote about the condition, which is also called involuntary emotional expression disorder, earlier this year -- and now the Food and Drug Administration has just approved the first-ever treatment for the little known condition, Reuters is reporting.

We must know: Tell us about the most inappropriate time a case of the giggles has hit you. (Crybabies, same question applies to you.)

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You know that saying "the left hand doesn't know what the right is doing"? For people with a strange disorder called alien hand syndrome, that's literally true -- the neuropsychiatric condition makes them feel as if one of their hands has taken on a mind of its own.

"An alien hand is an arm and hand that moves when the person to whom that arm belongs does not intend it to move," says Dr. Ken Heilman, a neurologist at the University of Florida College of Medicine in Gainesville, Fla. Heilman goes on to note that there are many neurological conditions that cause an arm to move unintentionally -- like seizures or tremors, and movement disorders such as chorea, dystonia and athetosis. Here's the difference: In each of those cases, if the arm moves, it's pretty much just flailing about purposelessly, "but with an alien hand, the movement appears to be purposeful." Creepy.

Heilman recalls one patient whose hands actually fought over fashion: Her right hand took a pair of red shoes out of the closet. Her left hand -- the "alien" hand -- pulled the red shoes out of her right hand, put them back and picked up a pair of blue shoes. When the right hand went again for the red shoes, the left hand slammed the closet door on the right hand.

A German neurologist and psychiatrist named Kurt Goldstein was the first to report a case of alien hand syndrome in 1908. His patient's left hand seemed to do whatever it pleased, including, at least once, an attempt to throttle its owner. It's most commonly the result of an injury to an area of the brain called the corpus callosum, which is, as Heilman describes it, "the major cable connecting the two hemispheres." (The injury often happens during surgery, such as an attempt to curb seizures, but it can also happen in stroke victims.) That injury prevents the two hemispheres from communicating, and because each side controls different behaviors and different hands, the confusion begins.

Usually, it's the left hand that is thought to be "alien," because that's the one controlled by the right hemisphere; the left hemisphere has no control over that hand, but it does control language, which gives the person the words to think, What is happening to my left hand?!

And it's always an alien hand, never an alien leg or foot. The brain has more bilateral control over the legs than it does the arms, Heilman explains. "The hand is this thing that does purposeful movement," he says. "We don't do a lot with our feet."

In one recorded case of alien hand syndrome, while a 67-year-old man slept, his hand did not; as a 1997 medical journal article reports, his hand "crept and crawled, especially at night, which caused him to awaken by grasping his collar." He solved his problem by wearing an oven mitt as he slept. But that guy had it easy. According to a 2000 journal article, a 73-year-old man's alien hand had a humiliating favorite hobby: masturbation.

Another more common (but less creepy) version of alien hand syndrome is an uncontrollable grasp reflex, which causes a patient to reach out and grab whatever is set in front of him, just like a baby would. (It's caused by an injury to the frontal lobe, which suppresses that grasping reflex as we mature.)

Alien hand syndrome is an extremely uncommon phenomenon -- most physicians have never even heard of it, says Heilman, who has only seen two patients exhibiting the more extreme kinds of symptoms. But it's popped up from time to time in pop culture.

The condition is sometimes known as "Dr. Strangelove syndrome," named for the titular character in Stanley Kubrick's famous 1964 film, in which Dr. Strangelove's right arm repeatedly tries to give a Nazi salute, and he must beat it down again and again with his left arm. More recently, "30 Rock's" live episode on Oct. 14 took on the spirit of the alien hand idea, featuring Jon Hamm in two fake, "Saturday Night Live"-style "commercials" for hand transplants gone totally wrong. (The late-1990s horror flick "Idle Hands" also nodded to the creepiness of the uncontrollable hand concept, but unless you, too, were a 14-year-old 8th grader in 1999 with a giant crush on Devon Sawa, you probably don't remember that one.)

In the real world, there isn't anything that can "cure" or even treat alien hand syndrome, Heilman says. Patients usually just come up with creative ways to keep their own appendages in check. "I had a patient who sat on his left hand," he says. "Many others treat their alien hand as if it were a disruptive child."

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You’ve seen them dance to Michael Jackson’s Thriller and read about their brain-eating adventures in the days of Jane Austen. There are zombie walks, zombie pub crawls and zombie flash mobs. Come Sunday, you’ll even be able to watch zombies in their own AMC TV series.

Yes, the walking dead are everywhere these days -- even in the mental disorders bible the DSM -- thanks to a rare neuropsychiatric disorder known as Cotard delusion, or walking corpse syndrome.

First described by French neurologist Jules Cotard in 1882, the delusion is linked to depression and brain injury in some cases, and thought to be neurologically related to Capgras delusion. In Capgras, a disconnect in the region of the brain that recognizes faces causes people to believe their loved ones are imposters. In Cotard’s, that disconnect results in them not recognizing their own face; as a result, they come to believe they’re dead.

But people with Cotard delusion don’t just think they’re dead. In advanced cases, they sometimes believe their flesh is beginning to rot or that some of their internal organs or their blood is missing.

Story: 'Walking Dead's' zombies are rising for TV dominance

In a case written about in the journal “Psychiatry” in 2008, a 53-year-old Filipino woman with Cotard delusion was admitted to a psychiatric unit after she told her family she was dead, smelled of rotting flesh and wanted to be taken to a morgue so she could be with other dead people.

Another case reported in 2008 involved a 28-year-old pregnant housewife from in Kashmir, India, who became increasingly depressed and eventually began telling people that her liver was “putrefying,” her stomach was missing and that her heart was “altogether absent.”

In another case from 2001, a 44-year-old man fell into a deep depression after he was unable to find work. Homeless, unemployed and unable to obtain psychiatric treatment, his symptoms worsened over a six-week period until he began to tell people that he had “melted away” and was “dead.” In the ensuing weeks, according to a letter in the journal Psychiatric Services, “his symptoms and daily functioning worsened. He continued to voice delusional beliefs, such as ‘my brain’s rotted away,’ ‘parts of my insides are gone’ and ‘I’m dead.’”

All three patients received treatment – and relief – through drugs and/or ECT (electroconvulsive therapy) and eventually came to realize they were not actually walking corpses.

But other individuals have not been as fortunate, particularly those who’ve fallen victim to a voodoo zombie curse. Practiced primarily in Haiti during the 18^th and 19^th centuries, the voodoo zombie ritual first involves slipping the potential victim a substance – usually a neurotoxin derived from the puffer fish -- in order to make it appear as if they’re dead. They’re then buried (sans embalming), and a day or two later, dug up and revived.

“But not to the point that they know who they are,” says Brad Steiger, author of “Real Zombies, the Living Dead and the Creatures of the Apocalypse.” “They’re in a perpetual trance, a twilight state. They’re brought back to serve as a slave for a voodoo priest or priestess.”

Steiger, who’s written about the paranormal for the last 50 years, says there have been many cases of "real-life zombies" over the years, many involving people who would spot a supposedly deceased relative working away in the sugar cane fields. He retells this spooky legend, which is included in his book: “There was a gentleman from Florida who went to Haiti and was dancing with a lovely young Haitian girl when he suddenly felt a prick on his arm,” he says. “He didn’t pay any attention to it, but the next thing he knew, he woke up with a hoe in his hand. He still had his suit and tie on but was working in the Haitian fields. Luckily, he was able to recover enough to eventually make it back to Florida.”

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Want to know what it’s like to be dead? Ask Julie Maeder, a 50-year-old certified image consultant from Troy, Mich.

"When I was 13 years old, I was in northern Michigan at my family’s cabin and came down with a 106 degree fever,” she says. “I remember trying to fall asleep and feeling too hot. And then I began to notice the room getting darker and the moonlight disappearing.”

After that, Maeder says, the really weird stuff began to happen. She started to float up towards the ceiling, even though her body was still lying on the bed. Her pain completely vanished and soon she was being pulled down a long, dark tunnel. At the end of the tunnel, there was a blinding white light and a sense of peace and calmness and utter joy.

“It was fantastic,” she says.

It’s also standard operating procedure for what Diane Corcoran calls a near-death experience, or NDE.

“There are about 15 characteristics that are universal in a near-death experience,” says Corcoran, president of the International Association for Near-Death Studies. “Some people will have one or two characteristics, some people have all 15.”

Corcoran says out-of-body experiences are just one hallmark of an NDE. Others include an immediate relief of pain, a feeling as if you’re traveling through a tunnel or to some other place, a feeling of being surrounded by bright light and an overwhelming sense of peacefulness. In addition, some people will see -- and even speak to -- departed relatives; others will see religious figures. Still more have talked about seeing flowers and hearing music -- and being filled with a tremendous sense of knowledge.

“Not everyone has all of them but we hear about these repeatedly,” she says. “There are also significant after-effects. People will come back with a whole different set of values; they’ll come back more affectionate and altruistic and less materialistic They’ll be more spiritual, although not necessarily more religious.”

The big question, of course, is whether the NDE is some kind of journey to the other side or whether it’s the body’s reaction to trauma. And there is evidence to support both theories.

Earlier this year, the medical journal Critical Care reported that Slovenian researchers had determined that people who reported near-death experiences had elevated levels of carbon dioxide in their blood and might be suffering from oxygen deprivation, the symptoms of which (particularly euphoria and the feeling of moving towards a light) can be similar to the symptoms of an NDE.

But Corcoran says studies attempting to debunk the millions and millions of NDEs that have been reported over the years are nothing new.

“People are always trying to find a reason to explain it away,” she says. “What usually happens is they can account for one or two of the characteristics, but they can’t account for all of the characteristics. How do you account for a 7-year-old who comes back knowing all about his dead grandfather from England who died in a fire, even though neither of his parents knew about it and the child has never left his own city block? Oxygen deprivation doesn’t account for those things.”

An international study launched in 2008 may provide more answers, though. Dubbed AWARE (short for Awareness During Resuscitation), the study will follow people who’ve gone into cardiac arrest in 25 hospitals in the U.S. and Europe. Researchers plan to monitor patients’ brain oxygen levels as well as test for out-of-body experiences, via a picture shelf installed high above the patients’ beds in cardiac ICUs (the patients will have to be “floating” outside of their body in order to see a photo on the shelf).

Unfortunately, results of the AWARE study won’t be released for at least two more years.

In the meantime, there’s always Clint Eastwood’s vision of the "Hereafter" to tide people over. Or experiences like that of Julie Maeder, who says that while her NDE happened nearly 40 years ago, it still resonates.

"When I told my parents about my experience after I woke back up in my bed the next morning, they said I must have been hallucinating because of the fever," says Maeder, whose fever broke at some point during the night when she saw the light. "But I still remember it. I’ll never forget it. And I can say that although I enjoy my life and don’t want to die any time soon, I’m not afraid of dying. I kind of think it’s going to be an unbelievable experience. I think we’re all going to a great place.”

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One January day in 2007, a terrifying idea seized a 45-year-old wife and mother in Omaha, Neb.: Her husband and teenage sons were not, in fact, her husband and teenage sons. Strangers who happened to be identical to her family members had taken over her home, and to fend them off, she armed herself with a fireplace poker, called her neighbors -- and 911.

It sounds like something out of the 1956 sci-fi film "Invasion of the Body Snatchers," but the Nebraska mom actually was suffering from something called Capgras delusion, a rare psychiatric disorder in which a patient believes her friends or family members are not who they say they are -- and that the real people have been replaced by identical-looking impostors.

Normally, we recognize faces thanks to a part of the brain called the fusiform gyrus, which is located in the temporal lobe. It processes the faces we see, and sends that information on to another part of the brain, the amygdala, which processes emotions. But in patients with Capgras, there's a disconnect between that visual center and the emotional center, explains Dr. Mariam Garuba, a New York psychiatrist who treated the Nebraska woman when she was admitted to an Omaha, Neb., emergency room three years ago. (Garuba wrote about the unusual case, referring to the patient only as "Ms. A," in a clinical psychiatry journal last year.)

In other words: Ms. A knew that these people standing in front of her looked, talked and acted like her husband and her children, but they didn't make her feel the way she usually did when she saw them.

It's worth noting that if Capgras patients talk to a loved one on the phone, they will recognize the voice. But if that loved one enters the room, the patient will accuse his friend or family member of being an impostor; that's because hearing and sight take different pathways to reach the brain's emotional center. (Extra credit: Watch neurologist V.S. Ramachandra deliver a fascinating speech on Capgras and other brain disorders at a 2007 conference.)

In some cases, that disconnect that is thought to cause Capgras is brought on by a head injury; in others, it's related to an existing psychiatric or neurological disorder. Ms. A falls in the latter group, as a longtime bipolar disorder patient who'd also been diagnosed with multiple sclerosis. Although she'd taken drugs to treat the bipolar disorder in the past, she was taking none in January 2007; she was also not taking any medication for her MS. Her physicians, including Garuba, believed the Capgras delusion occurred because of a relapse of Ms. A's MS. She was treated with antipsychotics, and after a few days, she gradually stopped believing that her doctors were trying to poison her; after nearly a month in the hospital, she stopped believing that her family members were impostors.

The rare disorder is named for Joseph Capgras, a French psychiatrist who was the first to write about the delusion in 1923, after treating a woman who became convinced that her husband and others she knew were actually body doubles. Similar cases to Ms. A's in recent years include a 24-year-old woman who, after some complications with pneumococcal pneumonia led to epileptic seizures, began to believe that some of the ICU physicians had been replaced by impostors. And in the UK, a 42-year-old woman claimed that while she was in the ICU for pneumonia in 1999, each of her family members except for her mother were replaced by aliens.

Of course, we don't know exactly how these patients voiced their suspicions, but it must have at least carried the spirit of this quote from the 1950s "Body Snatchers" trailer: "Listen to me! Please, listen! If you don't -- if you won't -- if you fail to understand -- then the same incredible terror that's menacing me will strike in you!"

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Beyond the traditional werewolf legends and the big, bad hotness of Jacob Black in the “Twilight” saga, is there any truth behind the notion of a man or woman actually transforming into an animal?

Yes and no, says Ben Radford, managing editor of the Skeptical Inquirer and author of “Scientific Paranormal Investigation: How to Solve Unexplained Mysteries.”

“There are conditions that are basically lycanthropic conditions,” says Radford, who has investigated ghosts, lake monsters, and mysteries like the chupacabra for a dozen years.

A likely physiological explanation for the werewolf legend is a genetic condition known as generalized hypertrichosis, which causes hair to grow excessively all over the body, including the hands and face, Radford suggests.

Although rare -- there have probably been only 50 described cases since the Middle Ages -- the condition has been well documented. In fact, lovelorn Mexican circus star Larry Ramos Gomez, better known as “Wolfboy,” is a Body Odd all- star for his efforts to develop a reality dating show (as of yet, the show hasn’t materialized).

In generalized hypertrichosis, all of the normally invisible hairs on the human body are replaced with thick coarse terminal hairs.

“There are apparently a very small number of people where virtually all the areas of the body that would have vellus hair seem to have terminal hair,” says Dr. Daniel Aires, director of the division of dermatology at the University of Kansas Hospital. “Those are the people who look like wolves.”

Other famous personages with generalized hypertrichosis include the so-called “Hairy Family of Burma,” Stephen Bibrowski, later known as "Lionel The Lion-faced Man," and Fedor Jeftichejev, more commonly known as Jo-Jo, the Dog-Faced Boy, a wildly popular Barnum & Bailey sideshow performer during the early 20^th century.

It can affect women, too. Julia Pastrana, the famous Bearded Lady of the mid 1800s, had a dual condition of generalized hypertrichosis with gingival hypertrophy, which caused excessive dark hairs all over her body as well as distorted facial features and enlarged gums.

Only last year, researchers discovered the genetic mutations responsible for the Bearded Lady’s rare condition.

Hypertrichosis isn’t the only possible basis for some of the werewolf myths. Cushing’s Syndrome, a hormonal disorder caused by high levels of cortisol in the blood, can cause symptoms of excessive hair growth, a fatty hump between the shoulders, pink or purple stretch marks on the skin and hyperhidrosis (excessive sweating). Then there’s porphyria, a blood disorder which makes people sensitive to light, may stain the teeth red and can lead to excessive hairiness.

“The combination of those things may have given rise to the Dracula or the Wolfman legends,” says Aires.

Psychological conditions may also be responsible for a little full moon hairy madness. “There are people living today who are absolutely convinced they’re werewolves,” says Radford.

The werewolf legend may make for spine-tingling fiction and smoking-hot movie characters, but, in the end, it traces back to a time when there were a whole lot of ‘monsters’ that wouldn’t be considered that way now.

“Basically, anything that made a person appear different would lead people to attribute that person to being a werewolf or a vampire. I’m well steeped in monster tradition but in terms of modern reports of werewolves, they’re not terribly common,” says Radford.

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Considering copying Lady Gaga's meat dress, which she wore to last month's MTV Video Music Awards, for your Halloween parties next week? A new video from the Newark, N.J.-based Star-Ledger explains why this is a terrible idea.

1. You will spread gross bacteria everywhere.

2. You will drip blood everywhere. As one New Jersey butcher told the reporter, "If it's fresh meat you're going to get blood, juice over everything you touch or sit on so it's not very hygenic."

3. It's surprisingly expensive! It'll take about 50 pounds of meat to cover you, costing you $250 or more.

4. You will be very cold, as there is "no insulating value at all," one of the butchers says.

5. You will be even colder when your whole costume falls apart. Another of the butchers remarks, "Beyond the sanitary aspects, there's the question of connective tissue. I mean, if you're sewing something like this together there's a very good possibility it's going to split through the grain and fall apart."

Luckily, you still have about a week and a half to think of a non-gross costume idea -- our friends at TODAY have a handy costume guide ready to go.

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Dizzy doesn’t begin to describe Gene Pugnetti’s bouts of vertigo.

For at least four years, the 56-year-old Yakima, Wash., man has suffered repeated episodes of stomach-lurching, head-spinning disruptions in his equilibrium, attacks so severe that they require him to sit down, cover his eyes and wait an hour – until the Valium kicks in.

Just since February, Pugnetti has endured 45 such spells, all caused by what doctors diagnosed as a severe case of Meniere’s disease, an inner ear disorder that erodes victims’ hearing and leaves them vulnerable to unexpected vertigo. The most recent bout was three weeks ago.

“It was pretty bad,” said Pugnetti, an information technology worker, who has 65 percent hearing loss in his right ear. “Just, bang!, you’re focusing on something and then all of a sudden you can’t focus on anything.”

Pugnetti has tried almost everything to quell the problem, which affects some 615,000 people in the United States, according to the National Institutes of Health. Drugs, diet, exercise and even an implanted shunt failed to do the trick.

On Thursday, though, Pugnetti became the first person to be implanted with a new device aimed at stopping the vertigo as soon as it starts. Dr. Jay Rubinstein and Dr. James Phillips of the University of Washington’s otolaryngology-head and neck surgery department, assisted by a team of experts, chose Pugnetti as the first member of a 10-person clinical trial to test an invention four years in the making.

It’s the “UW/Nucleus Vestibular Implant,” a clunky name for the behind-the-ear device that’s basically a revamped version of a cochlear implant, an electronic aid typically used to help deaf people hear. In Meniere’s, the disease short-circuits the power supply that allows balance, Rubinstein said. The new device restores it by sending electrical impulses to electrodes implanted in the bony ear, disrupting the vertigo.

Once it’s turned on, in about three weeks, Pugnetti will be able to don the device at the first sign of dizziness, disarming symptoms ranging from mild to severe.

It won’t eliminate the Meniere’s, for which there is no certain cause or cure, but it should get rid of the worst effect. If the clinical trial is a success, the device that was tested in monkeys and approved in June by the Food and Drug Administration could find a wide audience of Meniere’s victims, says Pugnetti, who has no qualms about being first.

“The fact is, there are a whole lot of people who are out there suffering,” he said. “Just talking about this procedure to them gives them hope. And that’s a big deal."

For information about the new device, call (206) 598-8896.

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Catherine Arnold writes: When it comes to video games, some people don’t let anything stand between them and a high score. Not even bystanders, it seems, who are turning out to be the collateral damage in the quest for video game greatness.

A new study of injuries that occurred as a result of, say, an over-eager dash at the electronic pins in Nintendo Wii bowling or the swing of a racket in interactive tennis shows that bystanders were being injured in the line of fire.

The study, done by the American Academy of Pediatrics, looked at the 696 video game-related injuries reported between 2004 and 2009. Of those, nearly one in five injuries were to bystanders while the rest were to those playing the game.

A common injury to bystanders was facial laceration (ouch!) as well as trauma to the shoulder, ankle and foot. Most injuries happened when a player was mimicking the movements done in actual activities such as boxing, bowling and tennis, researchers found.

Dr. Patrick O'Toole, the lead study author, says that he and his colleagues became curious about the real injuries from virtual, interactive games as they grew in popularity: "We felt that the injury pattern would be significantly different to traditional gaming injuries."

So, how to prevent facial lacerations and other icky injuries from overzealous gaming? O'Toole says, "Participants should be able to freely mimic the activity without being impeded by obstacles."

In other words, they should be able to arc the tennis racket, move their bowling arm back and forth lustily, and even downward-facing-dog without someone standing right next to them.

Or, to boil it down to two very un-scientific words: Stand back!

Have you ever injured an innocent bystander during a fast and furious Wii tournament? Or have you ever been injured this way?

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Unnhh! Ahhrroooo!

Some sound like growls, others sound like sirens, but no matter what a tennis player’s grunt sounds like, new research has found it actually helps by throwing their opponent off their game.

In a study conducted by Scott Sinnett, a psychology professor at the University of Hawaii, 33 undergraduate students watched tennis players hitting balls – with some of the tennis players grunting as they hit. Researchers then had the students indicate the direction of the shot immediately afterwards.

Turns out grunting not only slowed down the students’ response time – it caused them to make more mistakes in guessing the direction of the shots.

“In a nutshell, if the shot included a grunt, the students were slower and less accurate with their response,” says Sinnett. It's kind of like "icing" an NFL kicker, which we've written about before.

Sinnett hopes that his research will help to shed light on some of the controversy that’s bubbled up the last few years with regard to grunting in women’s tennis. During the 2009 Wimbledon Championship, for instance, both spectators and tennis players complained about the loud shrieks and grunts coming from some of the players.

It's not just tennis. Loud, obnoxious grunting causes frequent complaints in fitness gyms and at least one high-profile lawsuit over a dispute in a New York spinning class.

Portuguese tennis star Michelle Larcher de Brito – a notorious grunter – has even been booed off the court after being accused of using her banshee-like grunts and shrieks to distract opponents. Her grunts have reportedly reached a decibel reading of 109. (That's louder than a subway train or a motorcycle, and it's almost as loud as a rock concert.)

“There are a number of findings that would suggest that a consistent grunt should actually help an opponent by drawing and focusing attention on the ball being struck, but this obviously isn’t how many players and spectators feel,” says Sinnett, who hopes to test out his findings on professionals tennis players next. “This project allowed us to look at the theoretical question of whether the basic lab findings can be extended to a real world situation while at the same time look at a debate in professional tennis.”

David Partikian, a 45-year-old Seattle merchant marine who’s played tennis for most of his life, says using some annoying trait to psych out an opponent is nothing new in tennis.

“There are all sorts of little things that super competitive people will do,” he says. “I used to play a guy who smoked while he served. He was daring you to smack it at him. This is how racket sports can be. It’s a psych out.”

Might these new findings might inspire a cacophony of groans, howls, and shrieks at the health club tennis court?

“I think a grunt should be reserved for a serve that’s going over a hundred miles per hour,” says Partikian. “Unless you’re at a pro level and ... it’s a huge athletic effort, it’s a bit of an exaggeration."

Do you grunt when you play sports or workout? Tell us about it in the comments.

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It happens to grown men. It happens to little boys. Even babies. Nocturnal penile tumescence (NPT), known these days as “morning wood,” is a universal human male trait. In fact, our very, very little bros get ‘em in utero. And it’s not just morning wood, it’s midnight wood and 3 a.m. wood, too.

That provides a clue as to why men have erections when we’re sleeping. NPT is very closely linked to rapid eye movement (REM) sleep. The exact mechanism at work has not yet been fully teased out, but during REM sleep activity in part of the brain called the pontine area (among others) increases. It’s thought that this triggers a cascade of events including the release of nitric oxide by nerve fibers in the penis. This cascade is mediated by androgen hormones like testosterone.

Though it happens in REM sleep, which is also associated with dreams, we don’t necessarily have to be dreaming about all the ways guys who go to Vegas have more fun than we do when we go to Vegas. After all, those in utero boys haven’t yet heard of the "gentlemen's club" the Spearmint Rhino. NPT does not depend on erotic visuals.

A 2005 article in the Journal of Sexual Medicine suggests that NPT serves an evolutionary purpose: “It has been speculated that the main function of nocturnal erections is to provide adequate engorgement of the corpora cavernosa, which then leads to increased tissue oxygenation. This is in turn [prevents] cavernous fibrosis, the histopathological basis for corporeal veno-occlusive dysfunction, which probably is the most common cause of organic erectile dysfunction.”

In other words, our brains are giving our penises a little nighttime workout, strictly for maintenance, to make sure we stay tuned up. Nothing to worry about.

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Linda Carroll writes: Anyone who’s walked out of a dark movie theater into bright sunlight knows how painful this can be to the eyes. Imagine how much worse it would be if, like the Chilean miners, you stepped into the light after spending months underground.

That’s why rescue personnel sent dozens of sunglasses into the shaft for miners to wear as they were pulled up to safety. (And not just any sunglasses -- $450 designer sunglasses from Oakley.) For further protection for their sensitive eyes, miners will spend their first few hours in dimly-lit hospital rooms as their eyes slowly adjust to light.

Our eyes have two sets of cells to deal with light and dark conditions, explains Dr. David Sarraf, a clinical associate professor of ophthalmology at the Jules Stein Eye Institute at the University of California, Los Angeles. The six million cone-shaped cells, officially called cones, are what allow us to see what is directly in front of us when the light is bright. These cells also allow us to see color.

Find more coverage of the Chilean miners' rescue

The cylindrical-shaped cells, called rods, are responsible for peripheral and night vision. As conditions darken, more and more of our 120 million rods are put to work. But it takes time for the rods to come on line. That’s why you’re almost blind for the first five minutes after you step into a lightless room, and why you can start making out shapes 20 to 30 minutes later.

It’s pretty safe to say that after months in a mine with no light, 100 percent of the rods are on the job, Sarraf explains. And those rods aren’t going to go off line in a flash. That’ll probably take several hours.

With no sunglasses to protect their eyes, the miners would experience significant pain when they hit direct sunlight. “If you jump into brightly-lit conditions with your eyes open you’re going to have stimulation overload,” Sarraf says. “You’re basically releasing a huge electrochemical impulse in one shot. That’s why our instinct is to decrease the light stimulus by squeezing our eyes shut. The pain is a protective mechanism.”

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It's not like we expect a McDonald's Happy Meal to be the pinnacle of health food. But this is astounding. (That is, if it's true.)

A New York City artist named Sally Davies bought a Happy Meal -- a hamburger and french fries -- in April. She put the food on her living room table -- and decided to watch what happened: not much, actually. She's taken a photo every day since, and the burger and fries look almost exactly the same as the day they were "fresh."

Davies is recording her science-experiment-meets-art-project on her Flickr, and bloggers can't get enough of it.

We can't say for sure whether this isn't a hoax, as a McDonald's spokeswoman is claiming. (And, as it turns out, the lengthy shelf life of the Twinkie is a hoax!) But it's certainly something to chew on. (Sorry.)

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Too much junk food and lack of exercise makes us pudgy. But new research out of Ohio State University suggests there may be another factor at play: too much light at night.

“We were looking at the increasing level of obesity and realized that light at night -- and by that I mean electricity, TV viewing at night, people using computers later at night ... has also been increasing,” says Laura Fonken, a neuroscientist at Ohio State University in Columbus and lead author of the study.

To see if there was a connection, Fonken and her colleagues conducted a series of experiments exposing laboratory mice first to 16 hours of light and then eight hours of either total darkness, dim light -- like you’d get if the TV was on in your bedroom -- or full bright light. The result? The mice that “watched TV” all night gained weight. It was the same with the mice exposed to bright light all night long.

It didn’t take long for the pounds to pile up, either.

“After one week, the body mass increased with the mice with light at night and continued to increase throughout the eight-week study,” Fonken says. By the end of the study, the mice in the light cycle had about a 50 percent increase in weight compared to mice in the dark.

You might think the mice that were staying up late were chowing down on food more than the others. Perhaps a few bags of Cheetos?

Not so, Fonken says. When looking at the total food intake and total activity, the researchers didn’t see any difference between the groups.

There was a difference, however, when it came to when the mice were eating.

“The ones with the light at night were eating more during their typical rest phase, when they would normally be sleeping,” she says. “They were eating about 55 percent of their food during their rest phase.”

Another experiment was conducted with the same parameters -- light at night or total darkness -- only this time the mice were only allowed to eat within their normal waking period.

The result: skinnier mice. Something about the light changed their feeding behavior and disrupted their metabolism, Fonken suggested.

Fonken and her team haven’t tested their findings out on humans yet, but she says this does have important implications for people.

“If you consume food at the wrong time of day, if you eat during your rest phase, it disrupts your metabolic parameters so you see an increase in weight,” she says.

The Ohio State research backs up prior studies showing that late-night eating influences weight gain. It also helps explain obese people who suffer night eating syndrome – where they obsessively consume calories at night – and seem to experience disruptions in their internal body clocks.

Fonken says this doesn’t mean we should all go to bed as soon as it’s dark out (which in some parts of the country would mean hitting the hay at 4 p.m. in the winter), but we should think about the levels of light we have when we sleep and be cognizant of when we’re eating.

“It could be that ambient levels of light seeping in could make a difference,” she says. “We don’t really know yet, but it might be better for people to have black-out curtains or wear sleep masks. And leave time between their bedtime meal and when they actually go to bed.”

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Bill Briggs writes: The news release from the science lab contained one eye-popping word: “Research discovers how the deaf have super vision.”

“Super?” Seriously? When we think of super sight, we flash on a caped man flying with an “S” on his chest, peering into hideouts with X-ray vision. Can Marlee Matlin see through walls? No.

But she does probably see more acutely than those who can hear. New research suggests that many congenitally deaf people possess two types of extraordinary sight: Expanded peripheral vision and the ability to detect motion imperceptible to the hearing.

For example, when people with normal hearing stand at a clock’s center and stare at the 12, they probably can see the 10 and 2. But those with congenital deafness typically can also detect the 9 and 3, says Stephen Lomber, an associate professor and researcher with the Centre for Brain and Mind at the University of Western Ontario.

Also, deaf people recognize when an object that appears stationary to those with hearing is actually moving very slowly.

“These are abilities that most of us as humans – or most animals – don’t have,” he adds. Until now, scientists have been unable to explain how this happens. But according to research published today in Nature Neuroscience, Lomber and his team found that people who are born deaf or who lose their hearing early in life tap a brain area called the auditory cortex. That swath of gray matter, meant to process sound, is rewired to boost sight.

They figured this out by testing cats – some born deaf, some with full hearing and then confirmed the results through interviews with deaf people. The scientists used banks of LED screens to gauge and compare the cats’ peripheral vision and motion detection. The team checked its findings by chilling and shutting off the deaf cats’ auditory cortexes. All the amplified vision normally exhibited by the deaf cats suddenly vanished.

“They lost the super part,” Lomber said.

The brain’s ability to remake itself may mean that congenitally deaf people also have keener senses of touch and smell, Lomber theorized.

“The brain is a pretty efficient structure,” he said. “It’s not going to let processing capacity go to waste. If it’s not going to use it on sound, it’s going to use it on something else.”

Are any of your senses especially keen? Tell us about it in the comments.

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Everybody has a gym story about the guy on the stair climbing machine next to you who is dripping so profusely and puffing so maniacally that you’re in constant danger from flying sweat.

(Whoa! There goes a drop.)

But why is it always a guy? Are women just more conscientious about frequent toweling?

No, says a new study from researchers at Osaka International and Kobe Universities in Japan. Their experiment, published in the journal Experimental Physiology, showed that men not only sweat more than women, something previous research has shown, but are better at it.

Men have a lower perspiration threshold than women, the study said, meaning, the authors suggested, that the male thermostat will trigger sweating at a lower temperature than the female thermostat. This was true for both trained and untrained men compared to trained and untrained women.

That thermostat is located in our heads -- literally -- explained Chris Minson, professor of human exercise physiology at the University of Oregon. When body temperature rises, the brain orders up more skin blood flow and the starts the sweat glands pumping. “The thermoregulatory control centers in the hypothalamus region of the brain respond differently with training,” he said. If an untrained person might normally sweat at, say, 99.1 degrees of body temperature, with training, that threshold could drop to, say, 98.8.

The Japanese scientists suggested that male testosterone might be behind the gender difference, but Minson, who knows and respects the Japanese team, was cautious. Controlling for every parameter in such experiments is tough, he said. It could be that men sweat more profusely because they are doing more work. Even if both genders exercised at the same V02 max, most men would be bigger and weigh more and so would be using more energy and generating more watts. Plus, their extra skin surface area means more sweat.

Also, Minson said, female body temperature rises and falls throughout the menstrual cycle, which could further muddy the waters.

Whatever the answer, years of anecdotal gym experience suggest that women really do have that whole toweling thing down.

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Finally, science explains the scrunchie, parachute pants and those Silly Bandz the kids today are crazy about: You bought them (and your kids are buying them) because the cool kids have them. A new study in the Journal of Consumer Research confirms what we already suspected -- people will buy really weird things in their quest to fit in.

"Social exclusion is a very painful experience, which makes it a strong motivator," explains Tyler Stillman, a visiting sociology professor at Southern Utah University, who is one of the study's co-authors.

In one experiment, researchers paired study participants with a partner who left midway through the study. Some of the participants believed their partners left because they didn't like them -- and those people were more easily talked into buying a silly school spirit trinket. In another study, people who felt excluded were more likely to say they were willing to try cocaine. Researchers say their findings could have real-life implications.

"I think people experience the threat of exclusion when they move to a new area, start a new job, or start college," says Kathleen D. Vohs, a marketing professor at the University of Minnesota. "My hunch is that people in these circumstances are more likely to buy products that enable them to connect to their new social circumstances."

For example, for new college students, that could mean buying and wearing a hoodie with the name of the university on it.

"This trend is probably especially pronounced among people who experience difficulty gaining social acceptance in their new environment," says Vohs.

So, does it ever work? Can you really buy your way into a group of friends?

"Ha, well -- I do think it works sometimes," Vohs says. "We know from decades of data, that when people want to fit in, one great strategy is to mimic or be similar to others with whom they would like to be friends. So showing a would-be friend that you have the same spending patterns (tightwad or spendthrift) as she does is a great way to show her that you are similar, which is a generally effective strategy to be likable."

What's the dumbest or priciest (or both!) thing you've ever bought in a misguided attempt to fit in? Did it work?

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Rebecca Adler writes: My game face has been known to cause genuine panic on the field -- mostly among race officials and umpires worried they’ve got some kind of medical emergency on their hands. Either they think I’ve somehow been severely sunburned on just one side of my face or they worry that I’m on my way to having heat stroke.

I have a condition called Harlequin Syndrome, which causes me to sweat and flush red on only on the left side of my body.

I got it the day after I was born, in the same way that anyone gets it -- by sustaining an injury to the sympathetic nervous system (the part of the nervous system that reacts to stress and flight-or-fight circumstances), according to Peter Drummond, a professor at Murdoch University in Perth, Australia.

(FYI, it was Drummond who first researched the condition and coined the catchy term “Harlequin Syndrome” in 1988 after researching others who have it.)

But it isn’t just general trauma to the sympathetic nervous system. It occurs at a very specific area of that system: the space right between the shoulder blades where the sympathetic nerves leave the spinal cord.

While many of the subjects in Drummond’s studies were unable to identify the cause of the trauma to the nervous system, mine left a road map in the form of a six-inch-long scar tracing the shape of my right shoulder blade. It was an emergency operation that caused the damage to my nervous system that would later earn me the nickname Two-Face -- Thank you, Tim Burton, for releasing the movie "Batman Forever" during my freshman year of high school! -- and cause every shirt I own to get sweat stains on only the left side.

Only about 200,000 people in the United States are thought to share in the phenomenon that is Harlequin Syndrome, which can affect either the left or the right side of the body. Some with the condition are even known to turn red on one side and sweat on the other side. Regardless, there is always a strict dividing line between the flushed, sweaty side and the cool, dry side. While there are no real treatments for the condition, there are also, luckily, no known dangerous side effects, says Drummond. This means that as long as we’re OK with strangers' panicked requests that we go to the emergency room, the constant disposal of only half-ruined T-shirts and the discomfort of feeling our heartbeat in only the flushed side of our faces, then those of us with the condition can sweat it out as much as we’d like.

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Jean leggings – known by the dreadful portmanteau “jeggings” -- have been declared hot again this fall, a fashion trend that begs a burning question: Aren’t those ultra-tight denim leggings a sure-fire recipe for yeast infections?

“Any tight clothing that restricts air circulation to the crotch area could lead to yeast infections,” says Dr. Betsy Evans, an ob-gyn at Issaquah Obstetrics and Gynecology in Issaquah, Wash., and former chief of staff at Overlake Hospital Medical Center in Bellevue, Wash. “Yeast flourish when it’s wet and moist and so if that area doesn’t dry out, women are more prone to infections. We see more yeast infections in women who wear really tight jeans or any kind of tight clothing.”

Of course, not everyone who dons a pair of jeggings will immediately come down with the telltale burning and itching of a yeast infection.

“Some of it has to do with how long you wear the jeggings,” says Evans. “If you wear them for a long period of time – all day, every day – it would increase your chances. If you’re wearing them once in a while and the genital area has time to dry out in between, then I think you’re probably okay.”

Incidentally, Evans says one of the treatments for yeast infection is to wear loose-fitting clothing or no underwear, like a skirt with nothing underneath. Could that mean Paris Hilton and Britney Spears have been suffering from chronic yeast infections all these years? “I’m not their gynecologist so I can’t tell you,” says Evans.

Amelia Pontes, a 25-year-old fashion blogger from Boston, says she’s been wearing jeggings steadily for two months but hasn’t had any gynecological issues as of yet.

“I don’t think I’ve worn a pair of regular jeans since I got my first pair,” she says. “I have about five or six pair at this point. But I don’t wear them super tight. They’re fitted and tight but they’re not constricting. I can breathe.”

As for whether all of her can breathe, Pontes says she’s not concerned about yeasties.

“I wonder if it’s one of those things that people always say – like your mom,” she says. “They just don’t want you to wear tight jeans. People said that about thongs, as well, or anything that comes out that’s not conservative. They attach some kind of harm to it – ‘Something will happen if you wear these!’ Next week, girls will get pregnant from jeggings.”

Health hazards aside, tell us: What's your opinion on jeggings? Do you love them? Or loathe them?

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