Clocking Neptune's Spin by Tracking Atmospheric Features

Science Daily — A day on Neptune lasts precisely 15 hours, 57 minutes and 59 seconds, according to the first accurate measurement of its rotational period made by the University of Arizona planetary scientist Erich Karkoschka.

"The rotational period of a planet is one of its fundamental properties," said Karkoschka, a senior staff scientist at the UA's Lunar and Planetary Laboratory. "Neptune has two features observable with the Hubble Space Telescope that seem to track the interior rotation of the planet. Nothing similar has been seen before on the four giant planets."His result is one of the most enormous improvements in determining the rotational period of a gas planet in almost 350 years since Italian astronomer Giovanni Cassini made the first observations of Jupiter's Red Spot. The discovery is published in Icarus, the official scientific publication of the Division for Planetary Sciences of the American Astronomical Society. Unlike the rocky planets -- Mercury, Venus, Earth and Mars -- which behave like solid balls spinning in a rather straightforward manner, the giant gas planets -- Jupiter, Saturn, Uranus and Neptune -- rotate more like big blobs of liquid. Since they are believed to consist mainly of ice and gas around a relatively small solid core, their rotation involves a lot of sloshing, swirling and roiling, making it difficult for astronomers to get an accurate grip on exactly how fast they spin around.

"If you looked at Earth from space, you'd see mountains and other features on the ground rotating with great regularity, but if you looked at the clouds, they wouldn't because the winds change all the time," Karkoschka explained. "If you look at the giant planets, you don't see a surface, just a thick cloudy atmosphere."

"On Neptune, all you see is moving clouds and features in the planet's atmosphere. Some move faster, some move slower, some accelerate, but you really don't know what the rotational period is, if there is even some solid inner core rotating."

In the 1950s, when astronomers built the first radio telescopes, they discovered that Jupiter sends out pulsating radio beams like a lighthouse in space. Those signals originate from a magnetic field generated by the rotation of the planet's inner core.

However, No clues about the other gas giants' rotation were available because any radio signals they may emit are being swept out into space by the solar wind and never reach Earth.

"The only way to measure radio waves is to send spacecraft to those planets," Karkoschka said. "When Voyager 1 and 2 flew past Saturn, they found radio signals and clocked them at exactly 10.66 hours, and they found radio signals for Uranus and Neptune. So based on those radio signals, we thought we knew the rotation periods of those planets."

But when the Cassini probe arrived at Saturn 15 years later, its sensors detected its radio period had changed by about 1 per cent. Karkoschka explained that because of its large mass, Saturn couldn't incur that much change in its rotation over such a short time.

"Because the gas planets are so big, they have enough angular momentum to keep them spinning at pretty much the same rate for billions of years," he said. "So something strange was going on."

Cassini's later discovery was even more puzzling that Saturn's northern and southern hemispheres appear to rotate at different speeds.

"That's when we realized the magnetic field is not like clockwork but slipping," Karkoschka said. "The interior is rotating and drags the magnetic field along, but because of the solar wind or other, unknown influences, the magnetic field cannot keep up with respect to the planet's core and lags behind."

Instead of spacecraft powered by billions of dollars, Karkoschka took advantage of what one might call the scraps of space science: publicly available images of Neptune from the Hubble Space Telescope archive. With unwavering determination and unmatched patience, he then pored over hundreds of images, recording every detail and tracking distinctive features over long periods of time.

Other scientists before him had observed Neptune and analyzed images, but nobody had sleuthed through 500 of them.

"When I looked at the images, I found Neptune's rotation to be faster than what Voyager observed," Karkoschka said. "I think the accuracy of my data is about 1,000 times better than what we had based on the Voyager measurements -- a huge improvement in determining the exact rotational period of Neptune, which hasn't happened for any of the giant planets for the last three centuries."

Two features in Neptune's atmosphere, Karkoschka discovered, stand out in that they rotate about five times more steadily than even Saturn's hexagon, the most regularly rotating feature known on any of the gas giants.

Named the South Polar Feature and the South Polar Wave, the features are likely vortices swirling in the atmosphere, similar to Jupiter's famous Red Spot, which can last long due to negligible friction. Karkoschka was able to track them over more than 20 years.

An observer watching the massive planet turn from a fixed spot in space would see both features appear exactly every 15.9663 hours, with less than a few seconds of variation.

"The regularity suggests those features are connected to Neptune's interior in some way," Karkoschka said. "How they are connected is up to speculation."

One possible scenario involves convection driven by warmer and cooler areas within the planet's thick atmosphere, analogous to hot spots within the Earth's mantle, giant circular flows of molten material that stay in the same location over millions of years.

"I thought the extraordinary regularity of Neptune's rotation indicated by the two features was something really special," Karkoschka said.

"So I dug up the images of Neptune that Voyager took in 1989, which have better resolution than the Hubble images, to see whether I could find anything else near those two features. I discovered six more features that rotate with the same speed. Still, they were too faint to be visible with the Hubble Space Telescope and visible to Voyager only for a few months, so we wouldn't know if the rotational period was accurate to the six digits. But they were really connected. So now we have eight features locked together on one planet, which is really exciting."

In addition to getting a better grip on Neptune's rotational period, the study could lead to a better understanding of the giant gas planets in general.

"We know Neptune's total mass, but we don't know how it is distributed," Karkoschka explained. "If the planet rotates faster than we thought, the mass has to be closer to the centre than we thought. These results might change the models of the planet's interior and could have many other implications."

New Theory On Origin of Birds: Enlarged Skeletal Muscles

Ostriches in South Africa's Kruger National Park. A developmental biologist is proposing a new theory of the origin of birds, which traditionally has been thought to be driven by the evolution of flight. The new theory credits the emergence of enlarged skeletal muscles as the basis for their upright two-leggedness, which led to the opportunity for other adaptive changes like flying or swimming. (Credit: © David Garry / Fotolia)

Science Daily — A developmental biologist at New York Medical College is proposing a new theory of the origin of birds, which traditionally has been thought to be driven by the evolution of flight. Instead, Stuart A. Newman, Ph.D., credits the emergence of enlarged skeletal muscles as the basis for their upright two-leggedness, which led to the opportunity for other adaptive changes like flying or swimming. And it is all based on the loss of a gene that is critical to the ability of other warm-blooded animals to generate heat for survival.

Dr. Newman draws on earlier work from his laboratory that provided evidence for the loss, in the common dinosaur ancestors of birds and lizards, of the gene for uncoupling protein-1 (UCP1). The product of this gene is essential for the ability of "brown fat," tissue that protects newborns of mammals from hypothermia, to generate heat. In birds, heat generation is mainly a function of skeletal muscles.Dr. Newman, a professor of cell biology and anatomy, studies the diversity of life and how it got that way. His research has always centered on bird development, though this current study, "Thermogenesis, muscle hyperplasia, and the origin of birds," also draws from paleontology, genetics, and the physiology of fat."Unlike the scenario in which the evolution of flight is the driving force for the origin of birds, the muscle expansion theory does not require functionally operative intermediates in the transition to flight, swimming, or winglessness, nor does it require that all modern flightless birds, such as ostriches and penguins, had flying ancestors. It does suggest that the extinction of non-avian dinosaurs may have been related to a failure to evolve compensatory heat-generating mechanisms in face of the loss of UCP1," says the scientist

The Smell of Danger: Rats Instinctively Avoid Compound in Carnivore Urine

Science Daily  — The mechanics of instinctive behavior are mysterious. Even something as simple as the question of how a mouse can use its powerful sense of smell to detect and evade predators, including species it has never met before, has been almost totally unknown at the molecular level until now.

Their findings were published online in the Proceedings of the National Academy of Science on June 20, 2011.David Ferrero and Stephen Liberles, neuroscientists at Harvard Medical School, have discovered a single compound found in high concentrations in the urine of carnivores that triggers an instinctual avoidance response in mice and rats. This is the first time that scientists have identified a chemical tag that would let rodents sense carnivores in general from a safe distance. The authors write that understanding the molecular basis of predator odor recognition by rodents will provide crucial tools to study the neural circuitry associated with innate behavior.The search began in 2006, when Stephen Liberles, now Assistant Professor of Cell Biology at Harvard Medical School, was working as a post-doc in the lab of Linda Buck. Buck was part of the team that won the Nobel Prize for identifying the receptors that allow olfactory neurons to detect odors. While in her lab, Liberles identified a new type of olfactory receptor, the trace amine-associated receptors (TAARs).Mice have about 1200 kinds of odor receptors, and 14 kinds of TAARs. In comparison, humans -- who rely more on vision than smell -- have about 350 odor receptors and five TAARs.Liberles's initial findings indicated that several of the TAARs detect chemicals found in mouse urine, including a chemical with enriched production by males. He wondered, could TAARs (which appear to have originally evolved from neurotransmitter receptors that mediate behavior and emotion) play a role in the social behavior of rodents? What other kinds of naturally occurring odors might they be able to detect?In Liberles's lab at Harvard Medical School, graduate student David Ferrero began a search for other natural compounds that were detected by the TAARs. Working with commercially available predator and prey urine (used by gardeners to keep pests out of their crops and by hunters to mask their own scent or as lures for prey), Ferrero discovered that one of the 14 TAARs, TAAR4, detected the odor of several carnivores.

It seemed they had found a kairomone, a chemical that works like a pheromone, except that it communicates between members of different species instead of members of the same species. Prior to this discovery, the only known rodent-carnivore kairomones were a volatile compound produced by foxes, but not in that of other predators, and two non-volatile compounds produced by cats and rats (which prey on mice). Volatile compounds aerosolize and can be smelled at great distances; non-volatile compounds need to be sniffed more directly, something that would not be helpful in avoiding a predator directly but rather their terrain.

"One of the things that's really new here is that this is a generalized predator kairomone that's volatile," said Ferrero.

For rodents, it's the smell of danger.

Ferrero identified the compound that activates TAAR4 as 2-phenylethylamine, a product of protein metabolism. He then obtained specimens from 38 species of mammals and found elevated levels of 2-phenylethylamineby 18 of 19 species of carnivores, but not by non-carnivores (including rabbits, deer, primates, and a giraffe).

"It's been known so long that predator odors are great rodent deterrents, but we've discovered one molecule that's a key part of this ecological relationship," Ferrero said.

In a series of behavior tests, rats and mice showed a clear, innate avoidance to the smell of 2-phenylethylamine. The behavioral studies were repeated using a carnivore samples that had been depleted of 2-phenylethylamine. Rats failed to show full avoidance of the depleted carnivore urine, indicating that 2-phenylethylamine is a key trigger for predator avoidance.

Lacking the gene for TAAR4, humans can't experience anything like what rodents do when they smell 2-phenylethylamine. To us, it has a mildly inoffensive odor. But trimethylamine, a related organic compound that activates TAAR5, a receptor found in humans, is deeply repugnant to people.

What happens between the receptors and the parts of the brain that trigger that avoidance behavior remains a mystery, one with direct medical relevance.

According to Liberles, "In humans, the parts of the brain that deal with likes and dislikes go awry in many diseases, like drug addiction, and predator odor responses have been used to model stress and anxiety disorders. Going from chemicals to receptors to neural circuits to behaviors is a Holy Grail of neuroscience."

"The neural circuits are like a black box, but here we have identified a chemical stimulant and a candidate receptor that trigger one behavior," Ferrero said. "We feel this is an important first step to understanding the neural circuitry of innate behavior."

This research was funded by the National Institute On Deafness And Other Communication Disorders.

DNA barcodes save rainforests

THE UNIVERSITY OF ADELAIDE

'DNA barcoding' allows for identification and tracking of individual logs or wood products. Image: szefei/iStockphoto Advances in DNA 'fingerprinting' and other genetic techniques led by Adelaide researchers are making it harder for illegal loggers to get away with destroying protected rainforests. DNA fingerprinting for timber products has grown in international recognition due to research led by the University of Adelaide that traces individual logs or wood products back to the forests where they came from. Professor Andrew Lowe, Director of the University's Australian Centre for Evolutionary Biology and Biodiversity, and Dr Hugh Cross, Molecular Biologist at the State Herbarium of South Australia, have been working with Singapore company Double Helix Tracking Technologies (DoubleHelix), a leader in applied genetics for forest trade and conservation. In a new paper published in the journal of the International Association of Wood Anatomists, Professor Lowe and Dr Cross say DNA science has made a number of key advances in the fight against illegal loggers. "Molecular marker methods have been applied to freshly cut wood for a number of years, and it's now also possible to extract and use genetic material from wood products and old samples of wood," Professor Lowe says. "We can use 'DNA barcoding' to identify species, 'DNA fingerprinting' to identify and track individual logs or wood products, and we can also verify the region the wood was sourced from. "The advancement of genetics technologies means that large-scale screening of wood DNA can be done cheaply, routinely, quickly and with a statistical certainty that can be used in a court of law. Importantly, these methods can be applied at a customs entry point to the country - certification documents can be falsified, but DNA cannot." An estimated 10 per cent of wood imported into Australia consists of illegally traded timber, which has been cut down outside designated logging areas or outside agreed environmental controls. Australian companies have been the first in the world to purchase timber products that use DNA fingerprinting, as part of proof of legal origin starting back in 2007 - European and American importers are now following suit. Jonathan Geach, a Director of DoubleHelix, says: "As the technology is now proven scientifically and commercially, we're looking at a large-scale application in the Congo Basin, as well as working with governments in Europe and America to tighten the grip on illegal timber trade. "Having Professor Lowe as a leading researcher from the University of Adelaide and as an active member of our team has been tremendously important in driving the role of DNA tracing in timber internationally." Professor Lowe says a number of improvements in genetic marker methods still need to be made, such as for old or degraded wood samples. "Nevertheless, the advances in the use of DNA to identify wood are exciting," he says. This research is closely aligned with another major project, to develop a 'DNA barcode' for every tree and grass species on earth. "The Barcode of Life projects will take five years to complete, but the information will lead to a step change in the way we can manage our species and ecosystems right across the globe," Professor Lowe says.

New toy helps kids with autism

VICTORIA UNIVERSITY OF WELLINGTON

"[Autistic children] often don't understand how they should control their voice and body." Image:Tramper2/iStockphoto A responsive, mechanised toy designed especially for autistic children six months and up has been created to teach positive play behaviours. 'Auti' develops speaking, touching, and collaborating skills. It shuts down in response to any negative behaviour such as hitting or screaming, but quickly responds to the slightest positive interaction such as speaking gently or stroking. Each sensor can be adjusted to respond appropriately to a child's individual characteristics.   "Autistic children find it difficult to play," says designer Helen Andreae, who developed Auti through an industrial design paper at Victoria University in the final year of her Honours degree last year under the supervision of lecturers Tim Miller and Edgar Rodríguez Ramírez.    "They have great difficulty using their imagination to develop even the simplest fictional scenarios and have even further difficulties playing with other children because they often don't understand how they should control their voice and body. This can scare other children away when they are trying to make friends.   "I have had an awareness of autism for a long time, through family discussions and through observing the autistic child of a friend. In developing my design challenge, I thought a toy which could help families dealing with autism would be a positive area to focus my energies on."   The toy was designed in consultation with a child psychologist who works with autistic children and a professor whose research specialty is teaching autistic children. Dr Peter Andreae from Victoria's School of Engineering and Computer Science did the computer programming.   Ms Andreae says the toy is currently a prototype, so she has only allowed children of friends and family to play with it to avoid damage.   "The response to it has been positive—children love the fluffiness of Auti which is made of possum fur," she says.   "If one day Auti was commercialised it would need further fine tuning and I'd look at broadening its functions for a range of teaching applications."

Ancient animals had powerful eyes

UNIVERSITY OF SOUTH AUSTRLIA

The compound eyes of a living insect - a predatory robber fly - showing the individual lenses. Image: University of Adelaide South Australian and international scientists have discovered that some ancient, primitive animals had excellent vision. The discovery has been revealed today in the prestigious journal Nature.   UniSA palaeontologist Dr Jim Jago, who was part of the research team, says evidence comes from Kangaroo Island fossils. He says the fossils, which are over 500 million years old, look like squashed eyes from a recently swatted fly.   “Our Nature paper reports extremely well preserved fossil eyes from Early Cambrian (approximately 515 million years old) rocks from Emu Bay on Kangaroo Island,” Dr Jago says.   “These are by far the most complicated eyes known from this period of earth’s history. Each eye is seven to nine millimetres across and comprises over 3000 tiny lenses.   “As yet, the animal to which these eyes belonged is unknown, but they may have belonged to a large shrimp like animal. However, the rock layers in which the eyes are preserved include a dazzling array of fossil marine animals, many being new to science. They include primitive trilobite-like creatures, bizarre armoured worms and large swimming predators.”   The Nature paper is titled: ‘Modern optics in exceptionally preserved eyes of Early Cambrian arthropods from Australia’. Authors are Dr Michael Lee from the SA Museum and University of Adelaide, Dr Jago, Dr Jim Gehling from SA Museum, Dr John Paterson from the University of New England, Dr Diego Garcia-Bellido from Madrid and Dr Greg Edgecome from the Natural History Museum in London. Dr Jago says modern insects and crustaceans have ‘compound eyes’ comprising hundreds or even thousands of individual lenses.   “They see their world as pixels, with more lenses meaning sharper vision,” he says.   “The fossil compound eyes have over 3000 lenses, giving them much sharper vision than anything previously found from rocks this old. The eyes are much more complex than anything found previously in rocks of similar age. The newly discovered eyes are as advanced as the eyes in many living insects such as robberflies. The arrangement and size of the lenses indicates that these eyes belonged to an active predator that was capable of seeing in low light.”   The Nature paper reports these eyes provide evidence that the rapid development of advanced vision helped drive the Cambrian explosion of life that began around 540 million years ago, the time when most modern animal groups first appeared and proliferated in the oceans of the Earth. Given the tremendous adaptive advantage conferred by powerful eyes for avoiding predators and locating food and shelter, there must have been tremendous evolutionary pressure to elaborate and refine vision, the scientists report.

Babies are specially attuned to our voices and emotions

 Neuroscience 

Young babies' brains are already specially attuned to the sounds of human voices and emotions, according to a report published online on June 30 in Current Biology.

Three- to seven-month-old infants showed more activation in a part of the brain when they heard emotionally neutral human sounds, such as coughing, sneezing, or yawning, than when they heard the familiar sounds of toys or water. That activity appeared in an area of the temporal lobe known in adults for its role in processing human vocalizations. The babies also showed greater response to sad sounds versus neutral ones in another part of the brain involved in emotion processing in adults.

The researchers say the discoveries fundamentally advance our understanding of infant development.

"Our results suggest that the infant temporal cortex is more mature than previously reported," said Evelyne Mercure of University College London. "It is a rare demonstration that specialized areas exist in the brain very early in development."

"It is probably because the human voice is such an important social cue that the brain shows an early specialization for its processing," added Anna Blasi of King's College London. "This may represent the very first step in social interactions and language learning."

The findings are consistent with earlier evidence that infants can extract subtle information from human speech. Newborns prefer to listen to their mother's voice and their mother tongue. Young infants also differentiate between the voices of men and women, children and adults.

In the new study, the researchers used functional magnetic resonance imaging (fMRI) to record brain responses in sleeping babies while they were presented with emotionally neutral, positive, or negative human vocalizations or nonvocal environmental sounds.

"We were very surprised to find that the area of the temporal cortex that responded to the human voice more than to environmental sounds was so similar in its location to the adult area showing the same specialization," Mercure said. "Infant fMRI is not an exact science, and finding results that were so similar to the adult literature was reassuring and surprising at the same time."

The findings in normally developing babies call into question what happens to this voice-specialized brain region in babies that go on to develop behavioral or neuropsychological disorders, such as autism or schizophrenia, in which social communication is affected.

"We are now carrying out more research in this area to help us understand how differences in brain development arise, if we can use these to accurately identify babies who will go on to suffer from disorders such as autism, and if they can be used to help measure the effectiveness of interventions," added study author Declan Murphy, also of King's College London.

Provided by Cell Press

"Babies are specially attuned to our voices and emotions." June 30th, 2011. http://medicalxpress.com/news/2011-06-babies-specially-attuned-voices-emotions.html

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Robert Karl Stonjek

Drink-fueled memory blackouts among students predict future injury risk

The higher the number of drink fuelled memory blackouts a student experiences, the greater is his/her risk of sustaining a future injury while under the influence, reveals research published online in Injury Prevention.

Memory blackouts refer to the inability to recall events; they do not refer to loss of consciousness as a result of drinking too much. Research indicates that alcohol alters nerve cell communication in the hippocampal region of the brain, which affects memory formation.

Hazardous drinking - and its consequences - "are pervasive on college campuses," say the authors, who report that around one in three students say they have experienced a memory blackout in the past year, and around one in 20 say they have had a period of drink fuelled amnesia within the past seven days. Women are just as likely to have blackouts as men, even though they drink less.

In 2001, around 600,000 college students were injured as a result of excess drinking in the USA, and in 2005 almost 2,000 died as a result of booze fuelled unintentional injuries.

The authors therefore wanted to find out if the number of times a student had a memory blackout as a result of drinking too much could usefully predict who might sustain a potentially serious injury while under the influence in the future.

They analysed data from almost 800 undergraduates and more than 150 postgraduate students at five universities in North America between 2004 and 2009, who were monitored for two years.

The students were taking part in the College Health Intervention Project Study (CHIPS), which compared the value of screening and brief doctor-led interventions versus nothing for problem drinking, assessed according to quantity and frequency.

During the previous 28 days, male problem drinkers had put away an average of just under 82 drinks (as opposed to units); their female peers had downed just under 59.

Men had more heavy drinking days, defined as five plus drinks, than women.

More than half of all the students had had one or more memory blackouts in the 12 months leading up to the start of the study; 7% reported six or more during this time.

Those aged between 18 and 20, "sensation seekers," and those clocking up the most heavy drinking days reported the highest number of blackouts.

The subsequent analysis showed that the overall prevalence of injury associated with alcohol was just over 25%, with women just as likely as men to be injured.

And the more blackouts they had, the greater was their risk of unintentional injury.

One to two memory blackouts increased the odds by 57%. With six or more memory blackouts, a student was almost three times as likely to sustain an injury.

"Our results suggest that memory blackout screening at student health services could be a useful tool in college alcohol related injury prevention," conclude the authors.

This would be more specific than simply asking a student how much s/he drinks, and would help pick up those whose drinking is disrupting their cognitive abilities, they add.

"It may be easier for a student to dismiss general health warnings on excessive alcohol drinking harms than to refute that his extreme alcohol drinking is causing impairment in brain function," they say.

Provided by British Medical Journal

"Drink-fueled memory blackouts among students predict future injury risk." June 30th, 2011. http://medicalxpress.com/news/2011-06-drink-fueled-memory-blackouts-students-future.html

Posted by
Robert Karl Stonjek

NEW TITANIC

Brain scan reveals how our brain processes jokes

Neuroscience 

(Medical Xpress) -- A new Medical Research Council (MRC) study which has uncovered how our brain responds to jokes, could help to determine whether patients in a vegetative state can experience positive emotions.

Researchers from the MRC Cognition and Brain Sciences Unit (CBSU) used a brain scanning technique called functional Magnetic Resonance Imaging (fMRI) to watch and compare what goes on in the brains of normal individuals when they hear ordinary sentences and humorous jokes, including puns. By scanning the brains of twelve healthy volunteers, they found that the reward areas in our brain light up when processing jokes to a much greater degree than when we hear normal speech. This reward response increased with how funny the study participants found each of the jokes. 
  
Dr. Matt Davis, who co-led the research at the Medical Research Council CBSU, said: “We found a characteristic pattern of brain activity when the jokes used were puns. For example, jokes like ‘Why don’t cannibals eat clowns? Because they taste funny!’ involved brain areas for language processing more than jokes that didn’t involve wordplay. This response differed again from non-humorous sentences that also contained words with more than one meaning. Mapping how the brain processes jokes and sentences shows how language contributes to the pleasure of getting a joke. We can use this as a benchmark for understanding how people who cannot communicate normally react to jokes.” 
  
The authors believe they may be able to use this research to help discover whether someone in a vegetative state can experience positive emotions. 
  
Dr. Tristan Bekinschtein, lead author of the paper, said: “We’ve previously used fMRI to detect language comprehension in vegetative state patients who can’t communicate in any other way. This study shows we could now use similar methods to look for positive emotions in these patients. This is very important for the families and friends of these patients, who want to know whether they can still experience pleasure and ‘laugh’, despite their adversity.” 
  
Professor Susan Gathercole, director of the MRC CBSU, said: “This project demonstrates how even what might seem like idiosyncratic aspects of human experience, such as being amused, can be understood using the tools of neuroscience. There is a serious side to this. Being unable to take pleasure in everyday activities is a common symptom of depression. This research is an important part of the Medical Research Council’s commitment to explaining how the brain generates the experience of emotions and, ultimately, helping treat emotional problems.”

Provided by Medical Research Council

"Brain scan reveals how our brain processes jokes." June 30th, 2011. http://medicalxpress.com/news/2011-06-brain-scan-reveals.html

Comment:
"...because they taste funny!"  Their jokes were probably off ~ try a fresher one...

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Robert Karl Stonjek