A02 research

• Oswald's restoration theory: this explanation sees sleep as helping to reverse and/or restore biochemical and/or physiological processes that are progressuvely degraded during th day. It suggests that being awake disrupts homeostatis of the body and that sleep is required to restore it. High levels of sleep during REM sleep indicate brain restoration, while growth hormone production during the four stages of SWS indicated bodily restoration and repair. Oswald found tissue growth of new cells to take plus during sleep and also found high levels of ATP (an energy currency cell) during sleep.

• Horne proposed the core sleep model to explain the funtion of sleep. Horne explained that sleep acts to repair the function of the brain not the body. He conducted a meta analysis of 50 sleep deprivation studies and found that very few claimed sleep deprivation had effected their ability to do physical excercise. Therefore he concluded that 'core sleep' was essential for normal brain and cognitive abilities. 

Dement studied REM sleep deprivation in cats by placing them on upturned flower pots surrounded by water. When the cats would enter REM sleep their postural muscles would relax and they would fall into the water only to wake up. After 35 days of sleep deprivation the cats died.

• Shapiro found that people who had completed a marathon during the day slept for an hour and a half longer for two consecutive nights following the event.

• Lavie studied the effects of total sleep deprivation for 200 houea under controlled conditions with several ppts and found no long term detrimental effecs. However, each night brough worsened symptoms that included confusion and problems processing information.
• Contradictory research - Lavie who conducted a case study on a man who only slept 15 minutes a night, but was competenet with all brain functions.