The brain never stops working. But it does cease talking to itself when you lose consciousness, LiveScience said.
Scientists have long wondered what the brain does and doesn’t do during deep sleep. It remains active, they know. So what’s the difference between consciousness and the lack of it?
When we’re awake, different parts of the brain use chemicals and nerve cells to communicate constantly across the entire network, similar to the perpetual flow of data between all the different computers, routers and servers that make up the Internet.
In the deepest part of sleep, however, the various nodes of your cranial Internet all lose their connections.
“The brain breaks down into little islands that can’t talk to one another,“ said study leader Giulio Tononi of the University of Wisconsin-Madison.
Tononi’s team used a non-invasive procedure to activate select parts of the brain. Subjects had electrodes attached to their heads to monitor how each stimulation triggered reactions elsewhere.
In the early morning, when subjects were dreaming, signals careened around the noggin similarly to when they were awake. But at night, during deeper sleep, the picture was much different.
“During deep sleep early in the night,“ Tononi said, “the response is short-lived and doesn’t propagate at all.“
Consciousness has long mystified scientists. The new finding suggests that it depends on the brain’s ability to integrate information, Tononi says.
The compartmentalization might also help the brain’s synapses, which make all the connections that give us thought, to take a break, according to Tononi’s colleague, Marcello Massimini.
“This process would allow cortical circuits to eliminate noisy synapses and renormalize in order to be ready for the next day,“ Massimini told LiveScience. The reduced activity might also help explain why performance in various tasks improves after sleep, he said.
The machine used to conduct the experiments is new. It generates a magnetic field to provide stimulation, and Tononi’s team expects this to be the first of many similar studies that will help researchers better understand the mind and specific disorders of the brain.

Children whose mothers were overly stressed during pregnancy may themselves be more vulnerable to anxiety as a result, research suggests.
High levels of stress hormone may cross the placenta and affect the baby in the womb in a way that carries long-term implications, UK scientists believe.
According to Psychport, a Bristol University team found anxiety in late pregnancy was linked to higher cortisol levels in children aged 10.
The work in Biological Psychiatry tallies with earlier animal findings.
Past studies have shown stress in animals during pregnancy affects the body’s stress response system--the hypothalamic-pituitary-adrenal (HPA) axis which controls stress hormone levels, including cortisol.
But scientists have not been able to show that it also affects humans in the same way.
US psychologist Dr Thomas O’Connor, from the University of Rochester in New York, working with UK colleagues from Bristol University and Imperial College London, studied 74 children aged 10.
They analyzed saliva samples first thing in the morning and three times a day on three consecutive school days to monitor levels of stress hormones.
The children’s mothers had completed questionnaires 10 years previously, when they were expecting, about any stress or anxiety they were experiencing during their pregnancy.
The researchers looked back at this data to compare the results with those of the saliva tests.
The children with high levels of cortisol in their saliva tended to be born to the mothers who reported the most stress during their pregnancy.
Dr. O’Connor said, “These results provide the strongest evidence to date that prenatal stress is associated with longer term impact on the HPA axis in children.
“Our findings point to a possible mechanism by which prenatal stress or anxiety may predict these disturbances in early adolescence, and possibly into adulthood.“
However, he said much more work was needed to check that this was the case.
He also pointed out that it was not clear whether high cortisol itself could cause psychological disturbance. Some psychiatric disorders have been linked with low rather than high cortisol levels.
Other factors, such as the personality of the child and the environment they are living in, may play a part in childhood stress too.

A huge cliff, tens of kilometers high, crosses the face of Hyperion, in this view from 16,000 kilometers away.

After Cassini visited Saturn’s moon Tethys, it has flown past Hyperion, one of the smaller and odder moons of the ringed planet, New Scientist reported.
Hyperion is potato-shaped: 360 kilometers long, but only about 250 kilometers across. Its rotation is chaotic, tumbling unpredictably under the influence of Saturn’s and Titan’s gravity. And it is exceptionally dark for a Saturnian moon, reflecting only 30% of the light that falls on it, with a distinctly red tint.
The biggest question for Cassini to answer is why Hyperion is so misshapen when other asteroids and moons of about this size are much more spherical. One theory is that it is merely a fragment of a larger moon that was shattered in a violent impact.
Cassini’s pictures certainly show a tortured world, riven by craters and girdled by a giant cliff face tens of kilometers high.
The new images were gathered early on Monday morning, from as close as 500 kilometres to Hyperion’s surface. During the flyby, Cassini’s radar also measured slight changes in the speed of the spacecraft. This will give an idea of the strength of Hyperion’s gravity, and therefore its mass. Mission scientists hope to discover whether the moon is solid rock or a loosely packed “rubble pile“.
The Cassini team should also be able to map the chemical make-up of Hyperion’s surface to discover whether it is dusted with dark material drifting in from Saturn’s sooty outer moon, Phoebe.

Horseshoe bat is the likely source of the respiratory disease Sars, a new study suggests.
According to BBC News website, researchers found a virus closely related to the Sars coronavirus in bats from three regions of China.
Writing in the journal Science, they say the virus may have needed to infect another animal such as the civet before it could transmit to humans.
They suggest that live horseshoe bats are kept out of markets until the transmission path is fully understood.
The Sars (Severe Acute Respiratory Syndrome) outbreak in 2002/3 caused about 770 deaths, and economic damage estimated in billions of dollars; centered on east Asia with origins in southern China, fatalities occurred as far afield as Canada.
Schools and businesses closed, international trade and travel were restricted; and for a time, until basic public health measures curtailed the outbreak, it seemed as though the next major global disease of humanity had emerged.
But emerged from where? In May 2003, the suggestion emerged that the virus responsible had entered the human population from civets, animals eaten in wildlife restaurants and butchered in live animal markets in southern China.
The World Health Organization (WHO) endorsed this link early in 2004, an announcement which led authorities in China to embark on a culling program which saw an estimated 10,000 civets killed, as well as other animals suspected of harboring Sars, such as badgers and raccoons.

The area covered by sea ice in the Arctic has shrunk for a fourth consecutive year, according ananova.com.
US scientists say the area currently covered in ice is the smallest for more than a century.
Researchers conclude that human-induced global warming is at least partially responsible.
They warn the shrinkage could lead to even faster melting in coming years.
“September 2005 will set a new record minimum in the amount of Arctic sea ice cover,“ said Mark Serreze, of the National Snow and Ice Data Centre.
“It’s the least sea ice we’ve seen in the satellite record, and continues a pattern of extreme low extents of sea ice which we’ve now seen for the last four years.“
September is the month when the Arctic ice usually reaches a minimum.

Basic concept of a clamping capsule (a) before and (b) after gripper protrusion

Ability to perform measurements and obtain images at different locations along the human gastrointestinal tract would be of considerable benefit in various branches of medicine.
According to PhysicsWeb, in recent years several biomedical companies have developed so-called wireless capsules that can take images inside the gut after they have been swallowed.
However, these devices cannot be stopped at a particular location inside the gut because they are carried along by the natural process of peristalsis. This lack of a stopping mechanism means that certain areas of the digestive tract cannot be studied in detail.
Now Andrea Moglia of the CRIM Lab in Pontedera, near Pisa, and colleagues have developed a clamping system or “gripper“ that could be used to stop such capsules at specific locations of medical interest.
The gripper is made of a biocompatible nickel-titanium alloy that can be made to change its shape. The work could lead to the development of a pill that can perform biopsies in a non-invasive way.
The gripper is able to gently grip the walls of the intestine and it can move forwards and backwards with respect to the capsule thanks to two springs. The next stage is to attach a tiny video camera and battery to the capsule, which is just 26 mm long and 12 mm across.
The gripper relies on “shape memory alloys“--materials that respond to changes in the environment. In particular, these alloys are able to recover their initial shape when the temperature changes or when a mechanical stress is removed.
The new device is activated by a dedicated electrical interface. When current flows through a nickel-titanium wire, electrical energy is converted into mechanical energy and the gripper opens. When the current is switched off, the gripper closes automatically.
The scientists tested their prototype device in pig tissue and found that the gripper could exert a force of up to 0.6 Newtons on intestinal tissue. This is strong enough to overcome the peristalsis forces in the gut. The team now plans to increase the speed of the device and reduce its power consumption.

Navigating your way out of a puddle might not sound like a challenge, but to a tiny insect it is akin to scaling an extremely steep and slippery mountain, nature.com reported.
Two mathematicians have outlined exactly how little insects manage this feat: they turn surface tension to their advantage and ’surf’ up the edge with scarcely any effort.
The mountainous ridge of water at a puddle’s edge arises thanks to capillary attraction, which causes the liquid to shoot up where it touches the surrounding land. This feature, called a meniscus, is also commonly seen around the edge of a glass of water.
Large insects such as water striders (Gerridae), which are often found on pond surfaces, are fast enough and big enough simply to hurdle a puddle’s meniscus when they come to it. But smaller insects can’t do this.
Instead, insects that are just a few millimeters long deform the surface of the water with their legs, creating forces that shoot them to the top of the watery hill.
The insects are taking advantage of the same effect that causes pieces of cereal to come together in a bowl of milk, says Bush. Objects that deform a liquid and increase surface tension tend to attract each other once the deformed regions overlap, because this minimizes the overall amount of deformity, and therefore tension.
“It’s a very striking means of locomotion,“ says John Bush of the Massachusetts Institute of Technology in Cambridge, Massachusetts, who studied the phenomenon with his colleague David Hu. “It’s rare. It may even be unique.“

Stanford University School of Medicine researchers say they’ve developed a blood transplant procedure that can prevent fatal side effects, Science Daily said.
The researchers said the procedure can boost the relative levels of regulatory T cells--an effect that’s beneficial before hematopoietic stem cell transplantation, a common treatment for blood cancers.
Blood stem cell transplantation replaces cancerous blood cells of a leukemia or lymphoma patient with those from a healthy donor.
The transplantation cures the cancer, but in up to 80 percent of the cases there’s a potentially deadly side effect: The donor’s incoming immune cells attack the patient’s body as “foreign“ in what is known as graft-vs.-host disease.
The new therapy appears to block development of graft-vs.-host disease.
“It allows you to throw out the one effect, but not the other,“ wrote Dr. Samuel Strober, a professor of medicine at Stanford and senior author of the study.