Specific patterns in the nasal passageway that determine which olfactory neurons are associated with which particular odors have remained a mystery for scientists. The human nose has millions of these olfactory neurons grouped into hundreds of different neuron types. And each of these neuron types expresses only one odorant receptor in one region of the brain, allowing that specific odor to be sensed.

Now, researchers from UC Riverside and Stanford University have identified a braking mechanism in these olfactory neurons that helps generate an astonishing diversity of sensors in the nose.

As an example, the researchers said when a person smells a rose, only the neurons that express a specific odor receptor for the chemical emitted by the rose are activated. This in turn activates a specific region in the brain, allowing the person to sense the odor. Each smell activates a different group of neurons and also a different area of the brain.

In their study, the researchers focused on the olfactory receptor for detecting carbon dioxide in the fruit fly (Drosophila). Doing so, they identified a large multi-protein complex in olfactory neurons, called MMB/dREAM, that plays a role in selecting the carbon dioxide receptors to be expressed in specific neurons.

New research shows that people can process short sentences and solve equations before they're aware of the words and numbers in front of their eyes. The study suggests we might not actually need full consciousness to perform rule-based tasks like reading and doing math problems.

In a series of experiments at the Hebrew University of Jerusalem, more than 300 student participants were unconsciously exposed to words and equations through a research technique known as Continuous Flash Suppression (CFS). With this method, a static image appears in front of one eye while rapidly changing pictures flash in front of the other eye. The changing pictures dominate awareness at first, letting the still image register subliminally before popping into consciousness.

In the first part of the study, one eye was presented with a static phrase or sentence, which was "masked" by changing colorful shapes flashing in front of the other eye. The students were instructed to press a button as soon as they became aware of the words. It usually took about a second, but negative phrases like "human trafficking" and jarring sentences such as "I ironed the coffee" typically registered quicker than positive expressions and more coherent phrases such as "I ironed clothes," the study found.

The researchers say these results suggest that the sentences were fully read and comprehended subconsciously, and certain phrases broke out of suppression faster because they were more surprising.

Watching another person scratch an itch can cause you to do the same, and scientists have figured out the basis of this peculiar "itch contagion." It's all in your brain.

Merely seeing someone else scratch activates brain centers involved in the itch response, suggesting the observation makes one itchy.

But this response doesn't apply to everyone. Those study participants who were more neurotic (a tendency toward negative emotions) were more likely to experience itch contagion. Surprisingly, the researchers found empathy (a willingness to take another's viewpoint) did not correlate with the phenomenon.

"Before it was only anecdotal that people experience contagious itch," lead study author Henning Holle, a research fellow at the University of Sussex, told LiveScience. "There's a general tendency for people to experience contagious itch."

Catching an itch

To see where this happens in the brain, Holle and colleagues used functional magnetic resonance imaging (fMRI) machines to scan the brains of participants who watched silent videos of people either scratching or tapping themselves. (MRI scans show blood flow to active areas of the brain.)

Several regions of the brain already known to be involved in the itch response (both in "feeling itchy" and the related scratching behavior) lit up during the scratching videos. These included the premotor cortex, which influences motor activities, and the insula, a region behind the temples that activates when people experience empathy. However, during the tapping videos, these same brain centers didn't light up.

The researchers included psychological tests for the 51 study participants and found that empathetic people did not have heightened levels of itch contagion. Past research has suggested another contagious behavior, yawning, may be heightened for friends and family, suggesting contagious yawns may stem, in part, from empathy.

A certain level of excitement and anticipation exists when a conductor takes to the stage and taps his baton on the stand. Each member of the orchestra stiffens, ready to follow his timing, each playing their part when directed. While the conductor is clearly in control of the timing of the evening, there is nothing to stop one individual performer from stepping out on his own and causing complete chaos. One early strike by the percussionist throws the rhythm of the entire body off. This is an analogy proposed by researchers regarding how and why we might struggle with potential obesity.

Our fat cells are necessary because they store excess energy. These cells signal the brain, letting them know of their current energy storage level. It was in a study, published this week in the journal Nature Medicine that Georgios Paschos PhD, a research associate in the lab of Garret FitzGerald, MD, FRS director of the Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, showed that the removal of the clock gene Arntl, which also goes by the name Bmal1, in the fat cells of mice caused them to become obese. This occurred as a result of shift in the timing when this species, nocturnal in nature, would typically consume food. The researchers believe that this information could translate to the epidemic of obesity in humans, as well.

This Penn study is particularly surprising for two reasons. "The first is that a relatively modest shift in food consumption into what is normally the rest period for mice can favor energy storage," according to Paschos. "Our mice became obese without consuming more calories." Even without removing the clock gene from the fat cells, the researchers were able to replicate obesity in the normal mice simply by altering the timing of their food consumption

The realm of sleep and dreams has long been associated with strangeness: omens or symbols, unconscious impulses and fears.

But this sometimes disturbing world of inner turmoil, fears and desires is grounded in our day-to-day experience, sleep researchers say.

"The structure and content of thinking looks very much like the structure and content of dreaming. They may be the product of the same machine," said Matthew Wilson, a neuroscientist at MIT and a panelist at the New York Academy of Sciences discussion "The Strange Science of Sleep and Dreams" on Friday (Nov. 9).

His work and others' explores the crucial link between dreams and learning and memory.

Dreams allow the brain to work through its conscious experiences. During them, the brain appears to apply the same neurological machinery used during the day to examine the past, the future and other aspects of a person's (or animal's) inner world at night. Memory is the manifestation of this inner world, Wilson said.

"What we remember is the result of dreams rather than the other way around," he said.

When a sexual harassment case hits the news, people often "blame the victim," arguing that the harassed person didn't do enough to deflect the unwanted attention. Now, new research finds that this victim-blaming stems from the human tendency to overestimate oneself.

The more people assume they'll stand up to a harasser, the more they judge women who don't, a new study finds. The catch? Most evidence suggests people don't confront their harassers, even if they believe they would.

"They really falsely condemn them," said study researcher Ann Tenbrunsel, a professor of business ethics at the University of Notre Dame. "The basis of their condemnation is that they themselves would have done something differently, and chances are good they would not have."

Overestimating ourselves

Previous studies have found that people assume they'll stand up for themselves more in a confrontation scenario than they really will, a psychological tendency called behavioral forecasting bias. In one 2001 study published in the Journal of Social Research, for example, researchers asked women what they'd do if they were asked sexually inappropriate questions during a job interview. They all responded that they'd tell the interviewer off, report him or get up and leave. However, in an experiment that actually exposed women to sexual harassment in a fake job interview, not a single woman confronted or reported her harasser.

When you imagine standing up to a sexual bully, your main focus is on fighting back, said Kristina Diekmann, a professor of business ethics at the University of Utah and a co-researcher on the study. In a real job interview, however, other motivations become more important: avoiding an uncomfortable confrontation, getting along with others, getting the job.

"They're not thinking about taking action, they're thinking about just getting through this interview and getting the job," Diekmann told LiveScience.

Southland Times photographer Doug Field captured these images at the weekend of his dog, burying another dog.

Field, who was at Oreti Beach, near Invercargill, was walking his dog June when they came across dead hares and a dead dog.

What happened next was unusual, Field said.

June, ignored the hares, but spent the next 10 minutes using her nose, to flick sand up to bury the dead dog.

''There was quite a reverence in what she did. I've never seen another dog do that before.

''I'd love to hear from an animal behaviour expert to find out if this is common,'' Field said.

Being smart is the most expensive thing we do. Not in terms of money, but in a currency that is vital to all living things: energy. One study found that newborn humans spend close to 90 percent of their calories on building and running their brains. (Even as adults, our brains consume as much as a quarter of our energy.) If, during childhood, when the brain is being built, some unexpected energy cost comes along, the brain will suffer. Infectious disease is a factor that may rob large amounts of energy away from a developing brain. This was our hypothesis, anyway, when my colleagues, Corey Fincher and Randy Thornhill, and I published a paper on the global diversity of human intelligence.

A great deal of research has shown that average IQ varies around the world, both across nations and within them. The cause of this variation has been of great interest to scientists for many years. At the heart of this debate is whether these differences are due to genetics, environment or both.

One in three women suffer from the 'post-sex blues', according to Australian scientists.

More than 200 young women were quizzed on life between the sheets and 33 per cent reported feeling depressed after sex at some point in their lives.

The researchers are now trying to understand why some people experience the phenomenon.

Study author Robert Schweitzer, from the Queensland Institute of Technology, said: 'Under normal circumstances, the period just after sex elicits sensations of well-being, along with psychological and physical relaxation.'

But, he added, rather than any afterglow, some people instead have feelings of 'melancholy, tearfulness, anxiety, irritability or restlessness'.

'The findings are so counter-intuitive,' he continued. 'Everyone imagines sex as an enjoyable experience. But there seems to be a group of people who, in fact, experience distress following intercourse.

A new understanding of how the brain processes time could one day allow scientists to tweak an individual's sense of timing.

New research suggests timekeeping in the brain is decentralised, with different neural circuits having their own timing mechanisms for specific activities.

Not only does it raise the possibility of artificially manipulating time perceptions, but the finding could also explain why our sense of time changes in different conditions - such as when we are having fun or are under stress.

Two researchers from the University of Minnesota in Minneapolis trained to rhesus macaques to perform tasks requiring them to move their eyes between two dots in regular one-second intervals, New Scientist reported.

Despite having to external cues to help them keep track of time, after three months the monkeys had learned to move their eyes between the dots with average intervals of 1.003 and 0.0973 seconds respectively.

Using electrodes, the researchers then recorded brain activity across 100 neurons in the monkeys' lateral intraparietal cortex - the brain region associated with eye movement - as they performed the task.