Posts Tagged "Memory"

Almost a century after the discovery that sleep helps us remember things, scientists are beginning to understand why.

During sleep, the brain produces chemicals that are important to memory and relives events we want to remember, scientists reported this week at the Society for Neuroscience meeting in Washington D.C.

“One of the most profound effects of a night of sleep is the improvement in our ability to remember things,” says Ravi Allada, a sleep researcher at Northwestern University. Yet this connection hasn’t been well-understood, he says.

That’s changing, thanks to recent research from scientists including Jennifer Choi Tudor from the University of Pennsylvania. At the meeting, Tudor presented a study involving a brain chemical (known as 4EBP2) that is produced during sleep and is thought to play a role in remembering new information.

Previous experiments have shown that sleep-deprived mice have memory problems and lower levels of this chemical. So the team tried injecting the chemical into the brains of mice, then deprived them of sleep. “With the injection, their memory is normal,” Tudor says.

Sleep is also a time when old memories can be modified and new memories can be formed, says Karim Benchenane from the National Center for Scientific Research in Paris. Benchenane was part of a team that studied the brains of rats while the rats were awake, as well as during sleep.

When the animals were awake and traveling around their cages, the scientists identified brain cells that became active only when the rats were in a specific location. During sleep, these same cells became active in the same order, indicating that the rats were reliving their travels and presumably strengthening their memories of places they’d been.

Source: NPR

Waking up and not feeling rested isn’t just annoying. Researchers say that “non-restorative sleep” is the biggest risk factor for the development of widespread pain in older adults.

Widespread pain that affects different parts of the body — the main characteristic of fibromyalgia — affects 15 percent of women and 10 percent of men over age 50, according to previous studies.

To identify the triggers of such widespread pain, British researchers compiled demographic data as well as information on the pain and physical and mental health of more than 4,300 adults older than 50. About 2,700 had some pain at the study’s start, but none had widespread pain.

The results, published Feb. 13 in Arthritis & Rheumatology, show that restless sleep as well as anxiety, memory problems and poor health play a role in the development of this type of pain.

Three years after the study began, 19 percent of the participants had new widespread pain, the researchers found.

This new pain in various parts of the body was worse for those who had some pain at the beginning of the study. Of those with some prior pain, 25 percent had new widespread pain. Meanwhile, 8 percent of those with no pain at the start of the study had widespread pain three years later.

“While osteoarthritis is linked to new onset of widespread pain, our findings also found that poor sleep, [memory], and physical and psychological health may increase pain risk,” concluded the study’s leader, Dr. John McBeth, from the arthritis research center at Keele University in Staffordshire, England.

“Combined interventions that treat both site-specific and widespread pain are needed for older adults,” McBeth added in a journal news release.

Increasing age, however, was linked to a lower chance of developing widespread pain. Muscle, bone and nerve pain is more common among older people. Up to 80 percent of people 65 and older experience some form of pain on a daily basis, according to the news release.

While the study finds an association between poor sleep and widespread pain, it does not establish a direct cause-and-effect relationship.

SOURCE: Arthritis & Rheumatology, news release, Feb. 13, 2014

Regardless of how much time older Americans spend being active, those who sit for more hours each day are more likely to be disabled, according to a new study. Researchers found that every hour people 60 years old and older spent sitting daily was tied to a 46 percent increased risk of being disabled – even if they also exercised regularly.

“It was its own separate risk factor,” Dorothy Dunlop told Reuters Health. Dunlop is the study’s lead author from the Northwestern University Feinberg School of Medicine in Chicago. “We know that being active is good for your health and we know a sedentary lifestyle is bad for your health,” she said. But few studies have examined whether moderate to vigorous physical activity offsets the possible negative effects of being sedentary.

Dunlop and her colleagues write in the Journal of Physical Activity and Health that Americans already lead sedentary lifestyles. Among older Americans disability is also a major concern because it has been linked to increased medical spending and a higher risk of going into a nursing home or other care facility.

If future studies can confirm that sedentary behavior causes disability, which this study does not, then older people may possibly avoid becoming disabled by being more active throughout the day. For the new report, Dunlop and her colleagues analyzed data collected in 2003 through 2006 as part of a long-term government study of American health. The researchers used information on 2,286 adults who were 60 years old or older, had worn a device that measures physical activity for at least four days and had a physical exam. Participants were considered to have a disability if they couldn’t perform a self-care task, such as getting dressed, by themselves. Survey participants spent about 14 hours awake each day, on average. Of that, an average of nine hours was spent sitting or otherwise not moving.

After taking into account the amount of time people spent doing moderate to vigorous physical activity, their age, their health and whether they were well-off, the researchers found that each hour of daily sitting was linked to a 46 percent increased risk of having a disability. The study can’t say whether a sedentary lifestyle leads to disability or if having a disability leads to a sedentary lifestyle, however. In addition, the authors note that their records of physical activity may not take into account some forms of exercise, because the devices that participants wore may not pick up upper body movement or cycling. Participants also didn’t wear the devices while swimming.

Stephen Kritchevsky told Reuters Health it’s too early to tell if interventions that get people moving during the day will prevent disability, but they couldn’t hurt because other studies suggest activity improves functioning. He heads the Sticht Center on Aging at Wake Forest Baptist Medical Center in Winston-Salem, North Carolina and wasn’t involved in the new research. “The fact that people are physically limited in some way is even a bigger reason to try and do things, because there is plenty of research that shows that’s likely to improve function,” Kritchevsky said.

Dunlop said older adults should be as physically active as possible. They should also know that being sedentary is possibly bad for their health. “The goal here is to accumulate more light activities to replace the sitting and keep going on the moderate activity that you’re already engaged in,” she said.

SOURCE: (Reuters) Journal of Physical Activity and Health, online February 19, 2014.

Ever feel like a zombie after just one sleepless night? Your brains certainly do: According to a new study in the journal Sleep, a single night of sleep deprivation results in an uptick of two enzymes usually associated with brain damage.

Researchers from Uppsala Universityin Sweden put 15 young, well-rested and healthy men through a night of total sleep deprivation. When they tested their blood the next morning, they found higher concentrations of the enzyme NSE and S-100B — both biomarkers of cell damage in the brain that could lead to cognitive problems and memory loss.

These findings follow research earlier this year showing that sleep “cleans” your brain of toxins and other substances than can destroy your neurons. “With this finding in mind, once could speculate that the sleep loss-induced rise in circulating levels of NSE and S-100B in our study may be a result of increased neuronal damage,” says study author Christian Benedict, PhD, associate professor of neuroscience at the university. NSE is an enzyme found in all neurons, and S-100B is the “glue of the brain”, Dr. Benedict says. Some research suggests that S100B is important for information processing, and elevated levels make it easy for doctors to detect brain cell damage through a simple blood test.

The researchers havent yet conducted the experiment on women. But findings could apply, since the levels of NSE and S-100B were significantly higher compared to participants’ natural baselines. Still, the levels weren’t higher than those found after a concussion. “A single night of sleep loss is not equally harmful as head injury,” says Dr. Benedict. “However, it does suggest that getting a regular, good night’s sleep may be useful for supporting brain health.”

Read more about the study here.