PHILADELPHIA, Pa. — Whether you’re a baby being rocked to sleep or an adult dozing in a long car ride, it turns out everyone enjoys a few good vibrations when it’s time for bed. Researchers from Thomas Jefferson University say other species view gentle vibrations as non-threatening, shedding light on why humans fall asleep under similar stimuli.
“Babies like to be rocked to sleep, but the neural mechanisms underlying this well-known phenomenon remain largely a mystery,” Professor Kyunghee Koh says in a university release.
Experiments on fruit flies revealed the insects sleep longer when subjected to vibrations. The flies also become less responsive to light pulses that would otherwise wake them, but they become more awake afterwards thanks to accumulating “sleep credit.”
In other words, they act as if they slept more than they needed during vibration. This allows them to function well with less shut-eye later.
“We wanted to establish the fruit fly as a model system to study the mechanisms of sleep induction via vibration,” Prof Koh adds.
Vibrations improve sleep anywhere
The study suggests nodding off in a car is similar to regular sleep in a bed and serves some of the same vital functions. How much extra sleep the flies experienced depended on their genetic background as well as vibration frequency and amplitude.
The study, published in the journal Cell Reports, also discovered multiple sensory organs are involved in this process.
Interestingly, vibration initially makes flies more active than usual, but then starts to gradually put them to sleep. Also, the ability to go to sleep improves when exposure to vibration is repeated several times. Study authors believe this shows how simple learning skills play a role in species adjusting to vibrations.
“Flies learn over time that vibration is not threatening, which lowers their reaction to stimulation that would otherwise make them alert,” the associate professor of neuroscience explains.
The team believe that suppressing alertness is a key requirement for vibration-induced sleep. The study finds mutant flies with increased dopamine levels that make them more lively don’t fall asleep due to vibration. It is unclear whether similar mechanisms are at work in humans, but researchers find the brains of flies and humans are similar in how they form and function.
“Further investigation may help us develop and optimize sensory stimulation as a sleep aid for humans. Our findings suggest it would be worthwhile to personalize the stimulus parameters for each individual over several sessions,” Koh concludes.
A better night’s rest can save your life
Her team plans to identify specific neurons in the fly brain involved in the process. They also want to determine if vibration-induced sleep functions like normal sleep to boost memory and longevity.
Study authors believe repetitive stimulation of senses such as sight and smell could also trigger this effect. Finding ways to generate a better night’s sleep could be key to improving rest for people not getting enough sleep.
Studies find sleeping less than six hours a night increases the risk of a premature death by 12 percent. Poor sleep has also has a connection to a host of serious medical conditions including obesity, heart disease, and diabetes.
SWNS writer Mark Waghorn contributed to this report.