Is hydra A common animal. Less than half an inch long, its cylindrical body has one leg at one end and a mouth at the other. The foot is stuck on the sinking surface. A plant or rock, perhaps – and the mouth, the water washed in the tents traps the dwarf. It doesn’t have a brain, it doesn’t even have much of a nervous system.
And yet, New research shows, It sleeps. A team study from South Korea and Japan proved that Hydra periodically goes to rest that meets the required criteria for sleep.
In the face of this it may seem impossible. For more than a century, researchers have studied sleep to find its purpose and structure in the brain. They explored sleep connections with it Memory and learning. They calculated the neural circuits that led us down to our distracted sleep and pulled us back from here. They recorded tottle changes in brain waves that marked our passage at different stages of sleep and tried to understand what drives it. The mountains of research and the daily experiences of people give the truth of human sleep Connection to the brain.
However, a counter point to this brain-centered view of sleep has been revealed. Researchers have noticed that produced by molecules Muscles And Some other tissues Can control sleep outside the nervous system. Sleep affects metabolism extensively in the body, suggesting that its effects are not just nervous. And a body that has been quietly but steadily growing over the decades has shown that ordinary organisms with fewer and fewer brains spend significant time doing things that look a lot like sleep. Sometimes their behavior is simply pigeonholed as “sleep-like” but as more details are revealed, it becomes more or less clear why this distinction is necessary.
It appears that normal animals – at present, can sleep with a brainless hydra. And the disturbing effect of this finding is that the key role of sleep buried billions of years ago in the history of life may be very different from its standard concept. If no brain is needed for sleep, it could be a much broader phenomenon than we thought.
Recognition of sleep
Sleep is not like hibernation, coma, or fatigue or any other quiet state, wrote Henry Pyron, a French sleep scientist, in 1913. Although everyone is involved in the overly similar absence of movement, each of them has unique qualities and the daily obstacles our conscious experience was particularly mysterious. Without it a kind of foggy, confused, incapable of clear thinking. Researchers who wanted to learn more about sleep seemed to need to understand what it did in their brains.
And so, in the middle of the twentieth century, if you want to study sleep, you become an expert reader of electroencephalograms or EEGs. By placing electrodes on humans, cats or rats, the researchers were able to tell with certainty what subject they were sleeping on and what stage of sleep they were in. This approach created a lot of insights, but it was biased towards science: almost everything we learned about sleep came from animals that could be electroded, and the characteristics of sleep were increasingly defined by the brain activity associated with them.
This is frustrating Irene Tobler, A sleeping physiologist working at the University of Zurich in the late 1900s who began studying the behavior of cockroaches, wondering if a variety of insects sleep like mammals. After reading Pyron and others, Tobler knew that sleep could also be defined behaviorally.
He exhausted a set of behavioral criteria for detecting sleep without EEG. A sleeping animal does not wander around. Which is harder to extend than just resting. It can take a different pose than waking up or it can look for a specific place to sleep. Once awake it behaves more naturally than laziness. And Tobler added his own criterion, drawn from his work, to the rat: a sleeping animal that is disturbed will later sleep longer or deeper than usual, a phenomenon known as sleep homeostasis.