CDS 050808

Up, Up and Away ...
Half the world is living with double-digit inflation, as boom gives way to bust.



//////////////////As we snooze, our brain is busily processing the information we have learned during the day.
Sleep makes memories stronger, and it even appears to weed out irrelevant details and background information so that only the important pieces remain.
Our brain also works during slumber to find hidden relations among memories and to solve problems we were working on while awake.
In 1865 Friedrich August Kekulé woke up from a strange dream: he imagined a snake forming a circle and biting its own tail. Like many organic chemists of the time, Kekulé had been working feverishly to describe the true chemical structure of benzene, a problem that continually eluded understanding. But Kekulé’s dream of a snake swallowing its tail, so the story goes, helped him to accurately realize that benzene’s structure formed a ring. This insight paved the way for a new understanding of organic chemistry and earned Kekulé a title of nobility in Germany.

Although most of us have not been ennobled, there is something undeniably familiar about Kekulé’s problem-solving method. Whether deciding to go to a particular college, accept a challenging job offer or propose to a future spouse, “sleeping on it” seems to provide the clarity we need to piece together life’s puzzles. But how does slumber present us with answers?

The latest research suggests that while we are peacefully asleep our brain is busily processing the day’s information. It combs through recently formed memories, stabilizing, copying and filing them, so that they will be more useful the next day. A night of sleep can make memories resistant to interference from other information and allow us to recall them for use more effectively the next morning. And sleep not only strengthens memories, it also lets the brain sift through newly formed memories, possibly even identifying what is worth keeping and selectively maintaining or enhancing these aspects of a memory. When a picture contains both emotional and unemotional elements, sleep can save the important emotional parts and let the less relevant background drift away. It can analyze collections of memories to discover relations among them or identify the gist of a memory while the unnecessary details fade—perhaps even helping us find the meaning in what we have learned.

Not Merely Resting
If you find this news surprising, you are not alone. Until the mid-1950s, scientists generally assumed that the brain was shut down while we snoozed. Although German psychologist Hermann Ebbinghaus had evidence in 1885 that sleep protects simple memories from decay, for decades researchers attributed the effect to a passive protection against interference. We forget things, they argued, because all the new information coming in pushes out the existing memories. But because there is nothing coming in while we get shut-eye, we simply do not forget as much.


Features
The Hidden Power of Scent

Perspectives
Monkey Brains Hint at Evolutionary Root of Language Processing

Ask the Brains
Can one neuron release more than one neurotransmitter? Why is it comforting to discuss problems with others?

Then, in 1953, the late physiologists Eugene Aserinsky and Nathaniel Kleitman of the University of Chicago discovered the rich variations in brain activity during sleep, and scientists realized they had been missing something important. Aserinsky and Kleitman found that our sleep follows a 90-minute cycle, in and out of rapid-eye-movement (REM) sleep. During REM sleep, our brain waves—the oscillating electromagnetic signals that result from large-scale brain activity—look similar to those produced while we are awake. And in subsequent decades, the late Mircea Steriade of Laval University in Quebec and other neuroscientists discovered that individual collections of neurons were independently firing in between these REM phases, during periods known as slow-wave sleep, when large populations of brain cells fire synchronously in a steady rhythm of one to four beats each second. So it became clear that the sleeping brain was not merely “resting,” either in REM sleep or in slow-wave sleep. Sleep was doing something different. Something active.

Sleep to Remember
The turning point in our understanding of sleep and memory came in 1994 in a groundbreaking study. Neurobiologists Avi Karni, Dov Sagi and their colleagues at the Weizmann Institute of Science in Israel showed that when volunteers got a night of sleep, they improved at a task that involved rapidly discriminating between objects they saw—but only when they had had normal amounts of REM sleep. When the subjects were deprived of REM sleep, the improvement disappeared. The fact that performance actually rose overnight negated the idea of passive protection. Something had to be happening within the sleeping brain that altered the memories formed the day before. But Karni and Sagi described REM sleep as a permissive state—one that could allow changes to happen—rather than a necessary one. They proposed that such unconscious improvements could happen across the day or the night. What was important, they argued, was that improvements could only occur during part of the night, during REM.




////////////////////All too often the difference between success and failure, progress and regress, happiness and depression--and, yes, balance and imbalance--is simply a matter of perspective.

Paul Wilson
Business executive and author


Circumstances are the rulers of the weak; they are but the instruments of the wise.

Samuel Lover (1797-1868)
Novelist and songwriter



/////////////////////////