Dreaming in REM and NREM Sleep

The most fascinating part of human sleep, at least to writers and poets is dreaming. Sleep in humans is characterised by five distinct brain states, stages one through four, collectively referred to as non-REM (NREM) sleep and REM or rapid eye movement sleep. The term stage W is often used to refer to the wake state. REM sleep is characteristically different from NREM sleep in that the brain activation patterns more closely resemble brain activation in the waking state. In addition, humans experience muscle atonia during REM sleep, which is not present in NREM sleep. When researchers first studied this phenomenon, they noticed that when woken, subjects reported dreaming during REM sleep. This led to the theory that REM is responsible for dreaming. However, it had also been observed that dreams could occur during NREM sleep as well. Further research has shown that dreams occurring in REM sleep are quantitatively and qualitatively different from dreams occurring in NREM sleep. This paper will investigate those differences as well as the underlying brain mechanisms that accompany dream production. [...]