By Dr. David O. Volpi of Eos Sleep
What can bees teach us about the effect of sleep on memory and relearning? New research by Randolf Menzel of the Institute of Biology in Berlin, Germany explains.
According to Menzel, 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 has spent the last four decades studying honey bees. Menzel chose honey bees as his subjects because 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. Bees are also easy to train and well motivated.
About the study
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 home after they had found it one time. However, when the scientists interrupted the sleep of the bees just after they had learned a new direct route, the bees were disoriented during the second attempt to return home.
Fewer than half of the bees found their way back, 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.”
In summary, the well-rested bees were able to find the direct way home after brief training, but the sleep–deprived bees were disoriented. Sleep helps animals, including humans, to store new experiences in such a way that earlier memories can be altered and supplemented.
Read more about Menzel’s study in the article, “” in The Journal of Experimental Biology.