Every night, when people fall asleep and dream, their brains switch off the ability to control their bodies, paralyzing every muscle, Russian somnologists say.

Dreaming has two stages – synchronized sleep, and rapid eye movement or paradoxical sleep. It’s the second stage, which brings dreams to us. These two stages were first time detected, when the technique of electroencephalography appeared, which helped registering brain’s electric potentials. Researchers found out that during sleep human brain has several stages with different level of activity. First one was characterized with low activity level and was called synchronized sleep; and the second, when brain was almost as active as during daytime, got the name of rapid eye movement sleep. Characteristic feature of the second stage is that human eyes move very fast, and brain’s electroencephalogram resembles that of one, who woke up already.

For a long times scientists failed to explain why living beings needed to sleep, which made them vulnerable to various predators and other dangerous things. If you want to recharge your energies, all you have to do is to have some rest. Several explanations existed: one suggested that during sleep human organism got rid of toxins; another stated that sleep was essential for brain performance restoration. However, experiments showed that animals, subjected to sleep deprivation, inevitably died.

 

 

Researchers say that first genes, responsible for sleeping, appeared as long as about 3.5 billon years ago. These genes were connected with rhythms or biological clock and helped to adapt to nigh and day change. There is no way to fight sleeping in order to make waking period longer.

Scientists claim they now know what the functions of synchronized sleep are – during this stage brain restores its formation via a cascade of complicated processes. However, functions of paradoxical sleep are yet not clear – scientists know that rapid eye movement sleep plays a great role in brain development in young age (paradoxical sleep takes up to 90% of sleeping time), but they cannot explain why grown-ups, who have no more that 1.5 hours of paradoxical sleep during the night, dream. Young rats, which had no chance to dream, showed abnormal development of brain systems – they couldn’t properly see, communicate or sense. However, some people, whose need for paradoxical sleep is suppressed by antidepressants, live for many years without dreams and feel alright.

Scientists say that animals do dream, and they also have rapid eye movement or paradoxical sleep. A group of neurons in animal brains switch off muscles during this sleeping stage and paralyze the whole body. Brains block spinals cord to prevent us from doing what we are dreaming about. If a cat or a rat loses these paralyzing neurons, we will see animal’s dreams like in the cinema – a cat chasing a mouse or running away from a dog. Sleep paralysis helps us not to do harm to our dear ones, if we have a nightmare, for instance.

Source: RIA Novosti

Kizilova Anna