In the science news this week, exercise reorganises the brain to deal better with stress, Antarctic lake under two miles of ice found teeming with life, and finally... some cockatoos with a talent for complex puzzle solving.
Exercise reorganises the brain to help cope better with stress
A mechanism has been discovered by researchers at Princeton University that explains why exercise can reduce stress levels. The study found that regularly exercised mice responded to a stressful situation with a flurry of activity in the ventral hippocampus, an area responsible for regulating anxiety.
Exercise has long been known to reduce anxiety, but this research, published in The Journal of Neuroscience , is the first to explain exactly how. Exercising causes the creation of new neurons in the ventral hippocampus, which were previously thought to increase stress levels, but the study explains that keeping active also strengthens the processes that prevent these cells from firing, thereby reducing the anxiety response.
Mice in the experiment were split into two groups, one with access to a running wheel and one without. Mice will run several kilometres a day if they have access to a wheel, and after six weeks they were exposed to cold water. eScience News  reports that the two groups reacted differently to the stress, with sedentary mice showing an immediate anxious response; their brain cells leaping into an excited state.
Active mice reacted much more calmly, with a boost in the activity of a type of neurons that calm other brain cells down. They also release more of the neurotransmitter gamma-aminobutyric acid, or GABA, which stifles neural excitement.
The researchers hope that the study could bring new understanding to anxiety in humans, which could help to treat people with anxiety disorders.
"Understanding how the brain regulates anxious behaviour gives us potential clues about helping people with anxiety disorders. It also tells us something about how the brain modifies itself to respond optimally to its own environment," said senior author Elizabeth Gould.
The findings can be understood from an evolutionary standpoint, according to Gould. In the wild, an increased likelihood of anxiety in less physically fit animals could be advantageous if they are less able to escape predators. As a result, unfit mice would be more likely to avoid dangerous situations.
Under two miles of ice, Antarctic Lake Vostok is found full of life
Cores of ice from the world’s largest hidden lake have revealed thousands of organisms two miles under the Antarctic Ice, according to the BBC . Long thought to be sterile, Lake Vostok reveals a huge variety of life that could include fish and other animals.
The lake has been trapped under ice for over 15 million years, and now sits under two miles of glacial ice. As the lake’s liquid water freezes against the glacier, thousands of organisms are trapped in layers that can be dated and examined by scientists. So far researchers have discovered 3,507 organisms, including bacteria and fungi.
Speaking to The Telegraph , lead biologist Scott Rogers of Bowling Green State University said: "We found much more complexity than anyone thought. It really shows the tenacity of life, and how organisms can survive in places where a couple dozen years ago we thought nothing could survive. The bounds on what is habitable and what is not are changing."
The bacteria found include some that usually live in the intestines of fish, crustaceans and annelid worms, which could mean that larger animals are still living in the lake. According to the research published in PLoS One , Lake Vostok could harbour a variety of organisms that have evolved independently over millions of years in isolation.
In the time before Lake Vostok was covered by the glacier, more than 35 million years ago, it was surrounded by forest and could have been a marine bay. Tiny creatures were likely blown into the water by wind and rain, and could have made the lake their home. Rogers’ team say that these organisms may have slowly adapted to the changing conditions as Vostok was covered by ice.
Further drilling may be required to make any definite observations, since the cores used in the study were originally taken for research into the climate, and equipment was not always sterilised. "Debate about the accretion ice will continue until we get direct measurements and samples of subglacial lake water and sediments, taken under clean experimental conditions," Martin Siegert of the University of Bristol told the New Scientist .
Study shows that cockatoos can solve complex mechanical problems
An Indonesian species of parrot called a Goffin’s Cockatoo is capable of unlocking a complex series of different locks in order, according to a study published in PLoS One . Ten untrained parrots were presented with a box containing a nut trapped behind a transparent door, with five different locks standing between the parrot and its prize.
One parrot, named Pipin, figured the locks out in less than two hours. The others managed to complete the puzzle after facing each lock separately, or by having the unlocking process demonstrated to them.
The study indicates that these birds quickly understood the actions required to open each lock, and then remembered the process in later tests. The birds also persevered through the several stages of the task without giving up, showing an extreme determination. Have a look at the video on Sci-News .