Tag Archives: sleeping

Study Reveals Two-Thirds of Cats Favor Sleeping on Their Left Side

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Recent findings from researchers at Ruhr-University Bochum, Ankara University at Prince Edward Island, and Bari Aldo Moro University reveal that two-thirds of domestic cats (Felis Catus) tend to sleep on their left side. This orientation provides them with a left field of vision, allowing the right hemisphere of their brain to have an unobstructed view of impending approach, while protecting their body.

Isparta et al. We propose that the significant left-side preference in cat sleep may have evolved alongside hemispheric asymmetry related to threat assessment. Image credits: Noah Dustin von Weissenfrue / Gleb Kuzmenko / Isparta et al., doi: 10.1016/j.cub.2025.04.043.

“Sleep represents one of the most vulnerable states for animals, particularly during deep sleep when vigilance to threats is notably diminished.”

“Domestic cats act as both predators and prey (to animals like coyotes), averaging 12-16 hours of sleep per day.”

“This implies they spend around 60-65% of their lives in highly susceptible states.”

“To minimize the risk of becoming prey, cats tend to rest in elevated locations, where they can better see approaching threats while remaining concealed.”

“In such elevated spots, predators can typically only approach from below.”

“Thus, resting at height affords cats a sense of safety, comfort, and a vantage point to observe their surroundings.”

The authors of this study examined 408 publicly available YouTube videos featuring individual cats lying on their sides in clear sleep positions, ensuring unbroken sleep durations of at least 10 seconds with full visibility from head to tail.

Only original, unedited videos were considered; those that were low resolution, obscured, duplicated, or altered (such as mirror images or selfies) were excluded.

The findings showed that 266 cats (65.1%) exhibited left-oriented sleep positions, while 142 demonstrated a significant left-sided bias as a population, compared to the 34.8% that slept on their right side.

“A cat that sleeps on its left side gains awareness of its environment upon waking with a left field of vision processed by the right hemisphere,” explained the researchers.

“This hemisphere is critical for spatial awareness, handling threats, and coordinating quick escape responses.”

“When a cat awakens after sleeping on its left side, visual cues regarding predators or prey are relayed directly to the right hemisphere of the brain.

“This suggests that favoring the left side while sleeping might be a strategic survival behavior.”

study published in the journal Current Biology.

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Sevim Isparta et al. 2025. Sleeping orientations of domestic cats on both sides. Current Biology 35 (12): R597-R598; doi: 10.1016/j.cub.2025.04.043

Source: www.sci.news

The brain’s waste removal process disrupted by sleeping pills

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During sleep, your brain eliminates toxins that have accumulated throughout the day.

Robert Reeder/Getty Images

Sleeping pills may help you doze off, but the sleep you get may not be as restorative. When mice were given zolpidem, which is commonly found in sleeping pills such as Ambien, their brains were unable to effectively remove waste products during sleep.

Sleep is important for removing waste from the brain. At night, a clear fluid called cerebrospinal fluid circulates around brain tissue and flushes out toxins through a series of thin tubes known as the glymphatic system. Think of it like a dishwasher, which turns on your brain while you sleep, says Miken Nedergaard at the University of Rochester Medical Center in New York. However, the mechanisms that push fluid through this network have not been well understood.

Nedergaard and his colleagues implanted optical fibers into the brains of seven mice. By irradiating chemicals in the brain, the fibers can track the flow of blood and cerebrospinal fluid during sleep.

They found that elevated levels of a molecule called norepinephrine cause blood vessels in the brain to constrict, reducing blood volume and allowing cerebrospinal fluid to flow into the brain. As norepinephrine levels decrease, blood vessels dilate and cerebrospinal fluid is pushed back. Thus, fluctuations in norepinephrine during non-rapid eye movement (NREM) sleep stimulate blood vessels to act like pumps in the glymphatic system, Nedergaard said.

This discovery reveals that norepinephrine plays an important role in clearing waste from the brain. Previous research has shown that when we sleep, the brain releases norepinephrine in a slow, oscillating pattern. These norepinephrine waves occur during NREM, a sleep stage important for memory, learning, and other cognitive functions.

Next, the researchers treated six mice with zolpidem, a sleeping pill commonly sold under the brand names Ambien and Zolpimist. The mice fell asleep faster than those treated with a placebo, but the flow of cerebrospinal fluid in the brain was reduced by about 30 percent on average. In other words, “their brains aren't being cleaned very well,” Nedergaard said.

Although zolpidem was tested in this experiment, almost all sleeping pills inhibit the production of norepinephrine. This suggests that they may interfere with the brain's ability to eliminate toxins.

It is too early to tell whether these results apply to humans. “Human sleep architecture is still quite different from mice, but they have the same brain circuits studied here,” he says. laura lewis at Massachusetts Institute of Technology. “Some of these basic mechanisms may apply to us as well.”

If sleeping pills interfere with the brain's ability to eliminate toxins during sleep, Nedergaard says, that means new sleeping pills must be developed. Otherwise, your sleep problems may worsen and your brain health may deteriorate in the process.

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Source: www.newscientist.com

A bumblebee can survive underwater for a week while sleeping.

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Bumblebees may be more resilient than previously thought

Aaron Bastin/Alamy

A lab error has revealed that hibernating bumblebees can survive for at least seven days even when completely submerged in water. This ability suggests that beleaguered insects are more resilient than previously thought.

Sabrina Rondeau I came across this discovery by chance while researching eastern bumblebees (St. impatiens) in a laboratory at the University of Guelph, Canada. One week, she was checking on the hibernating queen bees kept in a hibernation chamber, a tube filled with soil in the refrigerator, when moisture overflowed into the tube and four queens were submerged in the water. I noticed that I was sinking. “I was a little surprised,” she says. “I was sure the queens were dead.”

To everyone's surprise, after draining the water, the bees woke up unharmed. Rondeau had a hunch that undiscovered abilities were at work.

She systematically drowned 21 queens over seven days, and 17 of them, or 81%, survived the flood. “This is a very high survival rate, not much different than before. [hibernation survival] When there’s no water,” Rondeau says. This achievement is probably due to the fact that dormant bees reduce their metabolic rate. This means that bees require very little oxygen, which can be met by air stored within their bodies.

“Wow, the fact that you can submerge a land animal in water for a week and find that it's still alive is really amazing,” he says. Lars Chitka at Queen Mary University of London.

Male bees and worker bees die before the winter, but the queen bee endures the cold for up to eight months by hibernating, waking up in the spring to begin building a new nest. The number of queens that survive is directly related to future population growth.

These bees hibernate underground, so extreme weather can destroy their safe haven. “It's a pinch point in their life cycle,” he says Nigel Lane, Dr. Rondeau's supervisor at the University of Guelph, Canada. This is a problem because about a third of all bumblebee species are already in decline. Finding that they are physically adapted to survive potential flooding is “really, really good news,” he says.

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Source: www.newscientist.com

Using sleeping birds’ vocal muscle activity to create artificial songs

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During sleep, we can sporadically find patterns of neural activity in areas of the bird's brain that are activated during song production. Recently, it was found that patterns of activity during these silent plays can be detected in the vocal muscles of sleeping birds. In a new study, researchers from the University of Buenos Aires and CONICET employed a dynamic systems model for song production in suborder birds. Tyrani This is to convert the vocal muscle activity during sleep into a synthetic song.

Great Kiskadee (Pitangus sulfuratus) July 2011, Beeville, Texas, USA. Image credit: Tess Thornton / CC BY-SA 3.0 Deed.

“Dreams are one of the most intimate and elusive parts of our existence,” said Dr. Gabriel Mindlin, senior author of the study.

“It's very moving to know that we share something with species so far away. And the possibility of entering the mind of a dreaming bird – of hearing the sounds of its dreams. is a temptation that cannot be resisted.”

A few years ago, Dr. Mindlin and his colleagues discovered that these patterns of neuronal activity were transmitted to the syringe muscle, the bird's vocal organ.

They are able to capture sleeping birds' muscle activity data via recording electrodes called electromyograms and convert it into a synthetic song using a dynamical systems model.

“For the past 20 years, I have been studying the physics of bird calls and how muscular information is translated into calls,” Dr. Mindlin said.

“In this way, we can use the muscle activity patterns as time-dependent parameters in a bird song production model and synthesize the corresponding song.”

Trill electromyographic activity recorded during sleep and synthetic sounds generated by a dynamic model.Image credit: Doppler other., doi: 10.1063/5.0194301.

Many birds have complex muscle structures, so translating syringe activity into calls is a bit difficult.

“For this first piece, we chose Wonderful Kiskadi (Pitangus sulfuratus)“It's a member of the flycatcher family, a species for which we recently discovered the physical mechanism of its song and showed some simplifications,” Dr. Mindlin said.

“In other words, we selected species for which the first steps of this program were viable.”

The authors heard the sound emerge from the data of birds dreaming of territorial battles by raising the tops of their wings, a gesture reminiscent of calls used during daytime conflicts. I was incredibly moved.

“Imagining that lonely bird reenacting its territorial battles in my dreams really resonated with me. We have more in common with other species than we often realize.” said Dr. Mindlin.

This study presents biophysics as a new exploratory tool that can open the door to the quantitative study of dreams.

“We are interested in interacting with dreaming birds using these syntheses that can be implemented in real time,” Dr. Mindlin said.

“And for species that learn, to address questions about the role of sleep during learning.”

of study It was published in the magazine chaos.

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Juan F. Doppler other. 2024. Bird dream synthesis was featured. chaos 34 (4): 043103; doi: 10.1063/5.0194301

Source: www.sci.news