Does the brain function while sleeping?

I often try to catch the time when I fall asleep, but could never become successful to grab it. Scientists have also been working on this topic for several years, but they are still far from the facts. Recently they got some hints about the functions of sleep that support the brain and body.  

Sleeping is very important for our body. It helps to rejuvenate the body cells and eliminate unnecessary elements from the brain. Sufficient amount of sleep can boost your learning and memory power. I hope you people have already faced sleep problem. If you have really faced it, then you definitely know its effect on your mood, appetite and sexual desire. A healthy sleep can regulate and boost your sexual desire, appetite and mood.  

According to research, two different types of sleep are produced in the brain called slow wave sleep (SWS) and rapid eye movement (REM). Most of us have SWS type which is also known as deep sleep. During SWS, the brain and body muscles function slowly and the person takes deep breathing. People need to have SWS to energize their brain and body function. 

According to scientists, there are two groups of cells available in the brain called the ventrolateral preoptic nucleus which exists in the hypothalamus and the parafacial zone that are responsible for SWS. When these cells produce SWS in the brain, we fall asleep or become unconscious. 

After SWS, people go to REM sleep mode. In this condition, their brain start dreaming and their muscles become paralyzed. Their lungs and heart show irregular performance too. However scientists have already got several successes in the field of biochemistry and neurobiology, they haven’t yet known the science behind REM sleep after several researches.  

REM sleep is regulated by subcoeruleus nucleus, a small group of cells found in the brain stem. If these cells stop functioning or work poorly, the muscle paralysis doesn’t occur during REM sleep. In this condition, REM sleep behavior disorder can be seen in people. It is a kind of disorder in which they act aggressively.

Source: https://www.scientificamerican.com/article/what-happens-in-the-brain-during-sleep1/