Evaluating the Restoration Theory of Sleep

This theory suggests that sleep is RESTORATION FOR THE BRAIN AND BODY, from damage caused during the day.

Reminder 1. NEW TISSUE GROWTH, PROTEIN SYNTHESIS and MUSCLE REPAIR occurs during sleep.

2. Sleep is an important way of REMOVING WASTE PRODUCTS Reminder 2. Sleep is an important way of REMOVING WASTE PRODUCTS

Reminder 3. Sleep is an important way of REPLENISHING NEUROTRANSMITTERS. What are NEUROTRANSMITTERS?

Reminder They are CHEMICAL MESSENGERS which carry ELECTRICAL SIGNALS from neuron to neuron. They are important to keep us alert and for our body to function.

Reminder As we go through the day, the amount of NEUROTRANSMITTERS in our bodies DECREASES. REM Sleep replenishes (makes) NEUROTRANSMITTERS for use during wakefulness

Reminder SLOW WAVE SLEEP 4. During this stage of sleep GROWTH HORMONE is released. This stimulates PROTEIN SYNTHESIS i.e. production of new body tissue.

Reminder ADAM AND OSWALD (1983) suggest that in; REM SLEEP – the brain restores itself and in SLOW WAVE SLEEP (stages 3 and 4) – the body restores itself.

Evidence against the Restoration Theory of Sleep

HORNE (1988) suggests: CORE SLEEP OPTIONAL SLEEP Stage 4 and REM Stages 1-3 NREM sleep During REM, sleep repairs the brain for vital functioning. Restoration that takes place during optional sleep can occur just as readily in WAKEFUL REST

1. No ill effects from REM deprivation Studies have been done in either ; TOTAL SLEEP DEPRIVATON (deprived of SWS & REM) Or PARTIAL SLEEP DEPRIVATION (deprived of just one of the two – SWS OR REM)

Con’t Johnson et al (1974) said there was no difference between partial sleep deprivation and total sleep deprivation. No difference in terms of performance or the subsequent time spent sleeping.

Other studies on NO REM LAVIE ET AL (1984) 20 year old individual Head injured by shrapnel Experienced no REM No ill effects. He completed his education and practiced LAW.

2. Sleeping more after exercise? Shapiro et al (1981) researched marathon runners – they slept for about an hour more for TWO NIGHTS. SWS increased – does this SUPPORT OR CONTRADICT THEORY? Horne and Minard (1985) – put participants through exhausting tasks – they went to sleep quicker but did not sleep for longer.

3. Protein synthesis? The theory says NEUROTRANSMITTERS ARE INCREASED. Horne (1988) says: AMINO ACIDS (that make up proteins) are only available for 5 hours after a meal. Therefore PROTEIN SYNTHESIS (making proteins) is not possible during sleep.

Jim Horne (1999) asks…… Qu. If the body can repair itself under a wakeful state, what is the main purpose of sleep, physiological repair or neurotransmitter recovery? If REM is for neurotransmitter recovery, why do infants spend 50% of their sleep in REM, but by the first year they have half of that (when most learning occurs)?

4. Lack of REM is good for depression Studies into individuals with depression suggests LACK of REM SLEEP has positive consequences. WU ET AL (1999) – symptoms of depression are reduced in people DEPRIVED of REM.

5. Different patterns of sleep If sleep is purely restorative, why are there so many variations of sleep patterns across species?

Toddler and puppy http://news-hound.org/2-months-later-this-toddler-is-still-napping-with-his-puppy-dog/