Breakthrough study reveals why we sleep

The average human spends 26 years of their lives sleeping. That’s a lot of z’s, and for what? Interestingly, the question of why we sleep is one of the great mysteries of biology.

Most theorists believe that sleep is of particular importance to the health of our brains or nervous system. After all, the effects of sleep deprivation usually take a mental toll, often in the form of memory loss, hallucinations or even seizures. Interestingly, though, every animal ever studied needs to sleep in some capacity, regardless of the size of its brain or the complexity of its nervous system.

So what gives? Well, a breakthrough new brain study might finally offer an answer. The research, spearheaded by Giulio Tononi of the University of Wisconsin-Madison, represents the best evidence yet of what happens when we sleep, reports New Scientist.

Tononi’s team took slices from the brains of mice before and after sleep. They found that synapses, or connections between neurons, were 18 percent smaller when sampled after a period of sleep. In other words, it seems that the connections between neurons in our brains are being trimmed or weakened while we snooze.

It may seem anti-intuitive to think about sleep as a good thing when it’s shrinking your brain, but it turns out that a slimmer brain has more room the following day to make new memories. At least, that’s the theory. Sleep keeps the mind open to new experiences, and to building memories of those experiences.

“Sleep is the price we pay for learning,” explained Tononi.

The theory is not only corroborated by this study, but it also explains why we find it harder to concentrate and learn new information when we miss a night’s sleep. It’s because the brain has reached its capacity, so to speak; it needs to be pruned.

Previous findings are also consistent with this theory. For instance, EEG recordings have shown that the human brain is less electrically responsive at the start of the day than at the end, suggesting that the connections may be weaker.

If Tononi’s study makes you frightened to sleep, for fear of having your experiences trimmed off, not to worry. The research also found that some synapses were protected from the trimming process, always remaining robust. These areas are probably where the most important memories are being stored, the most essential bits of information.

“You keep what matters,” reassured Tononi.

Though naturally, that leaves open the question of what matters, and how the brain determines what matters. But that’s a mystery for another day.

credit: Bryan Nelson

Harvard yoga scientists seek proof of meditation benefit

Scientists are getting close to proving what yogis have held to be true for centuries — yoga and meditation can ward off stress and disease.

John Denninger, a psychiatrist at Harvard Medical School, is leading a five-year study on how the ancient practices affect genes and brain activity in the chronically stressed. His latest work follows a study he and others published earlier this year showing how so-called mind-body techniques can switch on and off some genes linked to stress and immune function.

While hundreds of studies have been conducted on the mental health benefits of yoga and meditation, they have tended to rely on blunt tools like participant questionnaires, as well as heart rate and blood pressure monitoring.

Only recently have neuro- imaging and genomics technology used in Denningers latest studies allowed scientists to measure physiological changes in greater detail.

There is a true biological effect, said Denninger, director of research at the Benson-Henry Institute for Mind Body Medicine at Massachusetts General Hospital, one of Harvard Medical Schools teaching hospitals. The kinds of things that happen when you meditate do have effects throughout the body, not just in the brain.

The government-funded study may persuade more doctors to try an alternative route for tackling the source of a myriad modern ailments. Stress-induced conditions can include everything from hypertension and infertility to depression and even the aging process. They account for 60 to 90 percent of doctors visits in the U.S., according to the Benson-Henry Institute. The World Health Organization estimates stress costs U.S. companies at least $300 billion a year through absenteeism, turn-over and low productivity.

The science is advancing alongside a budding mindfulness movement, which includes meditation devotees such as Bill George, board member of Goldman Sachs Group and Exxon Mobil Corp., and comedian Jerry Seinfeld. News Corp. Chairman Rupert Murdoch revealed on Twitter he is giving meditation a try.

As a psychiatrist specializing in depression, Denninger said he was attracted to mind-body medicine, pioneered in the late 1960s by Harvard professor Herbert Benson, as a possible way to prevent the onset of depression through stress reduction. While treatment with pharmaceuticals is still essential, he sees yoga and meditation as useful additions to his medical arsenal.

It’s an interest that dates back to an exchange program he attended in China the summer before entering Harvard as an undergraduate student. At Hangzhou University he trained with a tai chi master every morning for three weeks.

“By the end of my time there, I had gotten through my thick teenage skull that there was something very important about the breath and about inhabiting the present moment,” he said.

His current study, to conclude in 2015 with about $3.3 million in funding from the National Institutes of Health, tracks 210 healthy subjects with high levels of reported chronic stress for six months.

They are divided in three groups.

One group with 70 participants perform a form of yoga known as Kundalini, another 70 meditate and the rest listen to stress education audiobooks, all for 20 minutes a day at home. Kundalini is a form of yoga that incorporates meditation, breathing exercises and the singing of mantras in addition to postures. Denninger said it was chosen for the study because of its strong meditation component.

Participants come into the lab for weekly instruction for two months, followed by three sessions where they answer questionnaires, give blood samples used for genomic analysis and undergo neuro-imaging tests.

Immortality Enzyme

Unlike earlier studies, this one is the first to focus on participants with high levels of stress. The study published in May in the medical journal PloS One showed that one session of relaxation-response practice was enough to enhance the expression of genes involved in energy metabolism and insulin secretion and reduce expression of genes linked to inflammatory response and stress. There was an effect even among novices who had never practiced before.

Harvard isnt the only place where scientists have started examining the biology behind yoga.

In a study published last year, scientists at the University of California at Los Angeles and Nobel Prize winner Elizabeth Blackburn found that 12 minutes of daily yoga meditation for eight weeks increased telomerase activity by 43 percent, suggesting an improvement in stress-induced aging. Blackburn of the University of California, San Francisco, shared the Nobel medicine prize in 2009 with Carol Greider and Jack Szostak for research on the telomerase immortality enzyme, which slows the cellular aging process.

Build Resilience

Not all patients will be able to stick to a daily regimen of exercise and relaxation. Nor should they have to, according to Denninger and others. Simply knowing breath-management techniques and having a better understanding of stress can help build resilience.

A certain amount of stress can be helpful, said Sophia Dunn, a clinical psychotherapist who trained at Kings College London. Yoga and meditation are tools for enabling us to swim in difficult waters.

Source: Re-Am.com