More about REM-sleep
-Amount of REM-sleep positively correlates with IQ among children, that is: Intelligent children have more REM than usual.
-Selective REM-sleep deprivation has a similar effect to antidepressants such as Prozac on depression; a lasting positive effect that takes a few weeks to develop. And also, it seems that ALL medications that have an antidepressant effect causes some degree of selective REM sleep deprivation.
-In addition to the memory/consolidation hypothesis of REM sleep, there is the brain development hypothesis. REM sleep serves development of the brain. The hypothesis is supported by these facts:
--The period in our life that we spend most time in REM sleep is the same period in which our brain development is at its peak.
--The amount of REM sleep decreases throughout life from 70% of total sleep time as newborns, to 15% in late adulthood.
--New-borns of species that are born with well-developed brains (such as the guinea pig), spend proportionally less time in REM sleep than new-borns of species where the brain development is very active after birth (e.g. humans)