Consciousness, perception and body control in sleep

Study of sleep and dreaming seems to be a promising way towards the understanding of such intriguing phenomena, as human “consciousness” and “self awareness” – unlike in wakefulness, they can take up many different surprising shapes in sleep. Common opinion of sleep as a “state of unconsciousness” is, basically, incorrect – often consciousness can be retained in sleep; on the other hand, the feeling of “self awareness”, when experienced in a dream, can be utterly wrong.

Sleep can be considered a combination of several different phenomena – general relaxation, loss of consciousness, sleep paralysis, and various degrees of external stimuli perception distortions. This combination vary a lot with changes in sleep cycle phase – for instance, paralysis is usually absent in NREM phase, the body is just very relaxed; traces of consciousness, if present, can be extremely dim and slow, but usually quite adequate, as well as the traces of external situation perception. On the contrary, in REM phase with dreams body is paralyzed – mind has almost no control over it, consciousness can be as bright as when fully awake, but absolutely inadequate, and perception of real external cues can be distorted very much, kind of woven into the general pattern of “sleep hallucination”.

Here are some curios states of brain, experienced in REM phase:

The listed above conditions can occur in normal and healthy brain, but the list can be logically continued to include

And, finally, we can include the

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