Can Bees Teach Us About Sleep, Learning and Memory?

As I’ve mentioned in previous blogs, we live in an exciting time for sleep research—it seems that every month, new studies are being published that provide us greater insight into the causes and treatments for various sleep disorders. And this month was no exception.

In a new article entitled, “Sleep-deprived bees have difficulty relearning”  in The Journal of Experimental Biology, researcher Randolf Menzel of the Institute of Biology in Berlin, Germany explains his four-decade study with bees, and what the results are teaching us about the effect of poor sleep on memory and learning.

The phases of sleep known as rapid eye movement (REM) and slow wave sleep (SWS) are involved in cognitive memory, such as learning motor skills and consciously remembering. As a result, restorative sleep not only rejuvenates us, it also helps consolidate memories.

To learn more about this relationship between the brain, sleep and memory consolidation, Menzel spent the last four decades studying honey bees. Why bees you ask? Well, according to Menzel, they are easy to train and well-motivated. Also, the human brain is too complex to dissect the neurocircuits that are linked to our memories. With bees, Menzel could identify the tiny circuits that control specific behaviors in their brains.

For the study, Menzel and his colleague, Lisa Beyaert, investigated the ability of bees to learn new routes from their beehive to a new feeding site, and second, the effect that loss of sleep would have on the bee's ability to learn the new route.

They provided a hive with a well-stocked feeder and trained the bees to visit the feeder and return home. To track the bees' flight during the experiments, the researchers used tiny radar antennas glued to the backs of the bees.

Once the researchers saw that the bees had memorized the route from the hive to home, they intercepted some of the bees at the feeder and transported them to a new location before releasing them again to find their way home. For the second part of the experiment, the researchers shook the bees awake every five minutes at night.

The researchers found that the insects could remember the way back to the hive after they had found it one time. However, when the scientists interrupted the bees’ sleep just after they had learned a new direct route, the bees were disoriented during the second attempt to return home.

Fewer than half the disoriented bees found their way back to the hive, and it took them twice as long as the bees with the usual amount of sleep. Menzel explained, "Without sleep, the bees are not able to consolidate the memory of the previous experiences with the new experience. Formation of the new memory is only possible during sleep.”

The well-rested bees, on the other hand, were able to find the direct way home after some brief training, but the sleep–deprived bees were disoriented and struggled to find their way. As in humans, sleep helps animals to store new experiences in such a way that earlier memories can be altered and supplemented. In other words, sleep helps us create new memories that override the previous memories.

So, what can bees teach us from Menzel’s study? That healthy, restorative sleep is vital to learning and consolidating memories. So get some good sleep tonight. That goes for you too, bees.

Read more about Menzel’s study in the article, “Sleep-deprived bees have difficulty relearning” in The Journal of Experimental Biology.

Veterans with Sleep Apnea: A Growing Human Issue

Whether or not you personally know someone who has served in Iraq, Afghanistan or someplace else on foreign soil, our returning veterans deserve our help and attention. While many have the scars of physical injury, many more veterans bear silent scars. A little known fact but of increasing concern in the medical community is that a growing number of veterans are suffering from obstructive sleep apnea (OSA), and its symptoms can be devastating for our returning war heroes as they readjust to civilian life

Consider these statistics: According to the U.S. Department of Veterans Affairs (VA), one out of every five war veterans has been diagnosed with OSA — compared with only five out of 100 civilians in the general population. And between 2008 and 2010, the number of veterans who received medical benefits related to sleep apnea grew by 61 percent, from 39,145 cases in 2008 to 63,118 cases in 2010.

These numbers beg the question: Why do war veterans suffer from sleep apnea more than non-war veterans and civilians? Some VA doctors believe that it is due to the high number of repeat deployments to Iraq and Afghanistan — soldiers are being exposed to higher levels of dust, smoke, stress and violence.

But what is at the core of this connection between war, OSA and other related conditions, such as daytime sleepiness, memory loss, a decrease in work productivity, obesity, heart disease, diabetes, and hypertension. Researchers at the Wayne State University (WSU) School of Medicine are beginning to find out.

Since the mid-2000s, WSU researchers have been studying 145 American immigrants who left Iraq before the 1991 Gulf War, and 205 who fled Iraq after the Gulf War began. All lived in the Detroit area at the time, and were asked about socio-demographics, pre-migration trauma, how they rated their current health, physician-diagnosed and physician-treated OSA, and any somatic and psychosomatic disorders.

The study’s lead investigator, Bengt Arnetz, M.D., Ph.D., M.P.H., School of Medicine professor of occupational and environmental health, and deputy director of the Institute of Environmental Health Sciences at Wayne State said, “It may be the stress of war that leads to fractured sleep, and that no one had explored this possible link before, although basic research suggests it as plausible.”

The results of the study are published in the October 2012 issue of Psychosomatic Medicine in the article, "Obstructive Sleep Apnea, Post-traumatic Stress Disorder, and Health in Immigrants.” The research showed that those who left Iraq after the war began and suffered from mental disorders such as post-traumatic stress disorder (PTSD) and depression, and self-rated their physical health as worse than their actual health, were 43 times more likely than pre-Gulf War immigrants to report OSA and later develop major chronic health issues, such as cardiovascular disease.

On the results, Arnetz said, “It's a known fact that the more exposure to violence you have, the more likely you are to report post-traumatic stress disorder (PTSD) and depression, and the worse your self-rated health is, the more likely your actual health will suffer in five to 10 years.” And I reiterate, those who were exposed to the violence of the war in Iraq were almost twice as likely to experience PTSD and depression, but also Obstructive Sleep Apnea and other chronic health conditions. I applaud Arnetz and his colleagues’ efforts, and encourage them to continue their studies so that we in the medical community can better understand, diagnose and treat war- and stress-related health conditions.

What about treatment? Diagnosing OSA in veterans can be trickier than non-veterans because of the possibility of other military-related medical conditions, such as PTSD. In addition, some military veterans suffering from OSA may underestimate the health benefits of restorative sleep, rather than be properly diagnosed and treated since its common during deployment to have fractured sleep patterns.

The good news is that there is more awareness of OSA than ever before, especially within the military. Back in February 2012, Ventus Medical, the company that makes Provent Therapy, announced that the U.S. Department of Veterans Affairs approved a multi-year, Federal Supply Schedule contract that would enable more veterans to get Provent Therapy treatment — a small, non-invasive nasal device for the treatment of obstructive sleep apnea (OSA).

This is good timing, considering that a substantial percentage of veterans don't accept or adhere to continuous positive airway pressure (CPAP) therapy, even though it is a safe and effective treatment. According to Richard B. Berry, M.D., Professor of Medicine at University of Florida, "There is a great need for access to new, clinically-proven therapies—particularly easy-to-use treatments — for the increasing number of veterans with obstructive sleep apnea."

As more and more Iraq and Afghanistan veterans are realizing their post-war health problems, and because many Vietnam veterans are getting older, the number of veterans applying for OSA-related disability benefits will only continue to rise in the coming years. While OSA is a chronic condition creating a significant burden on the Veterans Healthcare System — the VA spends upwards of $500 million a year to treat veterans with sleep apnea — I believe that it is our duty as a nation to provide proper OSA treatment to our veterans to prevent additional chronic health issues. To read more about the study, go to the Wayne State University website.