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6

We don't actually know. But these two theories are strong candidates: Sleep 'cleans' the brain of toxins. Metabolic waste products of neural activity are cleared out of the sleeping brain at a faster rate than during the awake state. This finding suggests a mechanistic explanation for how sleep serves a restorative function, in addition to its ...


6

The brain does not "shut down" during sleep. While not everything about sleeping is understood, we do know that certain areas in the brain remain active during sleep. There is a good overview on sleep on the website of the National Institute of Neurological Disorders and Stroke. Until the 1950s, most people thought of sleep as a passive, dormant part of ...


4

No, you cannot. Although we don't know how sleep works, we know that lack of sleep is very devastating to the body, and nothing (including laying in bed relaxed but awake) can replace it. If a rat experiences 100% lack of sleep (somebody keeps it awake all the time), this will kill it sooner than 100% lack of food would. There are no wake-until-you-die ...


3

I think the reason is primarily, that it is more quiet (the chance is very low that other people are disturbing your sleep) in the night as well as it is also dark. Keeping in mind, that the brain "gets tired" due to some proteins (melatonin) and in contrast, being more awake during the day, it seems to be just logical that the sleep in the night is ...


2

A couple of quick google searches would tell you that the important part of sleep is the REM (Rapid Eye Movement) sleep. REM stands for rapid eye movement. During REM sleep, your eyes move quickly in different directions. That doesn't happen during non-REM sleep. Usually, REM sleep happens 90 minutes after you fall asleep. The first period of REM typically ...


2

Let's firstly differentiate deafness - profoundly impaired ability to hear, and other states where the subjects can still hear at different degrees. Secondly, differentiate the congenital deafness & infantile hearing loss and hearing loss in adults who previously had normal hearing. The subjects with congenital and very early infantile hearing loss ...


1

It appears that short wavelength light (that is light around the blue and purple end of the electromagnetic spectrum) does have a significant effect on melatonin levels and the 'alerting response'. Exposure to 2 h of monochromatic light at 460 nm in the late evening induced a significantly greater melatonin suppression than occurred with 550-nm ...


1

I don't believe either is the reason. Back in the day of early man, the different intensity levels of light was used as a signal to our body's "master clock" to tell us when it was time to go to sleep. So to simply put it, when exposed to less intense light, such as artificial light, its picked up as the dimmer, less intense, light akin to when historically ...


1

Yes, when you are dreaming, brain activity increases ( called the REM phase because of the effect of the increased neural activity: rapid eye movements ). You can tell this by looking at the EEG, from witch we can state that our brain is more active and therefore is consuming more energy, making the regenerative effect of the sleeping less efficient. ...


1

It's possible that they do, depending on the intensity of the dream and the amount of brain activity. For example, if the dreamer is thinking too much or is having a dream that's way too intense, the brain activity goes up and they're not as rested. However, lucid dreaming can be good for sleep if the dreamer creates a more relaxed dream. This can ...



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