Oswald's Restoration Model (1980)
Oswald suggests that the high level of brain activity seen during REM sleep reflects brain recovery, while an increase in the body's hormone activities (especially growth hormone) during SWS refelcts restoration and recovery in the body.
Oswald views REM sleep as essential for brain repair and restoration. This is supported by the high proportion of REM sleep seen in the new born baby, where it makes up 50-60% of sleep time, gradually falling to the normal proportion of about 25% as the child grows. The months before and after birth are a time of rapid brain growth and development, so if REM sleep is a time when such processes occur, it is logical that a baby should show increased amounts of REM sleep.
Horne's Core Sleep/Optional Sleep Model (1988)
In a review of the effects of sleep deprivation Horne concluded from a number of controlled laboratory studies that sleep deprivation in normal participants produces only mild effects, together with some sleep recovery concentrated mainly in Stage 4 and REM sleep.
Although the effects of sleep deprivation were not dramatic, they did involve sopme problems with cognitive abilities, such as perception, attention…