January & February 2015

Plan This term – pack completion should mainly be done outside lessons. 6 th and 9 th nature of sleep 13 th lifespan changes 16 th H group SLC, G group room th complete preparation, begin presentations 23 rd complete presentations 27 th to half term, sleep disorders 3 rd February subject review (L-Z), 6 th sleep disorders and review 10 th February new topic (parents’ evening)

Nature of sleep

What is sleep?

Humans spend about 1/3 of their lives asleep (perhaps 25 years) The animals that sleep for the shortest time are, in order, the giraffe (about 2 hours), horse, donkey, sheep, cow and elephant (about 4). Sleep is a feature of most living organisms. Dolphins experience unihemispheric sleep (one side of the brain), with the opposite eye open (left brain, right eye for instance). Dolphin sleepingDolphin sleeping Why sleep is important can be shown by the effects of lack of sleep. There are several reasons why animals (including humans) sleep.

Problems if lack of sleep indicate its importance

Defining and describing sleep. Sleep is an altered state of consciousness. It can be defined as a state of body and mind during which conscious awareness and bodily functions are suspended. It is characterised by lack of movement and by a change in brain wave patterns. Arousal or alertness can be measured using an EEG, EMG and EOG or measuring heart rate and breathing. Subjective measures can be used after someone has woken up.

Sleep has a circadian rhythm The stages of sleep comprise an ultradian rhythm that repeats about 5 times. There are four stages plus REM. 75% of sleep is NREM, 25% is REM.

Sleep including 5 stages Leon Lack lecture (from to sea lions) Leon Lack lecture

Outline the nature of sleep. (8 marks)

Mark scheme The nature of sleep conventionally refers to the basic characteristics of sleep. These include its circadian periodicity, the different phases and stages of sleep (REM and NREM, or REM and SWS), the association between REM sleep and dreaming etc. Different sleep patterns across the lifespan or across the animal kingdom would also be relevant. Given the problem of defining the ‘nature’ of sleep, a wide range of material could be relevant. These include the functions of sleep, sleep disorders, brain mechanisms of sleep and sleep as a biological rhythm.

Top band (7-8) Knowledge and understanding are accurate and well detailed. A good range of relevant material has been selected. There is substantial evidence of breadth and depth. Organisation and structure of the answer are coherent.

By next week: Read Lifespan changes in sleep (pages 8-10 in the pack) and complete.

Changes in sleep patterns with age Change in the number of hours of sleep Change in the relative amounts of deep and REM sleep

Hours of sleep (average) AgeAverage no. of hours of sleep Newborn18 1 to 12 months to 3 years to 5 years to 12 years9-11 Adolescents9-10 Adults7-8

Adolescence More control over going to bed and getting up, particularly at weekends and during the holidays Preference for staying up later perhaps but also likely to be due to changes in circadian rhythms (= phase delay) Social zeitgebers (e.g. getting up for school = phase advance) clash with biological rhythms (remember which tends to be stronger) Sleeping in late when possible only serves to shift biological clock (phase delay) Use of computer tablets with strong lights can also delay melatonin production if used in the evening or late at night Consequences of phase advance – like jet lag

Adulthood With age there can be additional factors that disrupt sleep patterns such as sleep apnoea. We will study this separately. However, the tendency to sleep for a shorter time and to experience reduced REM has been found in animals as well as humans (Naylor et al., 1997). Correlational research (the older someone is, the less sleep they have) does not indicate cause and effect. It may be that reduced REM is a direct consequence of biological changes over time or an indirect consequence of changes in lifestyle that reduce the requirement for REM.

Discuss lifespan changes in sleep (16 marks)

Functions of sleep Chapter in book on sleep lk8zfh2FY7Uzz0&hl=en&sa=X&ei=rjOtVLjuG8yAU9Gmg4AG&ved=0CEsQ6AEwBg#v=onepage&q=hours%20of%20sleep%20lifespan%20table&f=false Possible sources – go to psych205 for links. Prezi presentation on the evolutionary and restorative explanations (includes another explanation - information consolidation but you do not need to know this) Blind fish is a chapter from a book on sleep for A-level students. The whole chapter is useful but you can just look at the section on functions of sleep. TED talk

Disorders of sleep DSM IV (to V) Some sleeping disorders are classified as psychological abnormalities including: primary insomnia, sleepwalking and narcolepsy.

Insomnia Sleep walking four cases Lee sleep walking artist Narcolepsy

Today Either produce an overview or mindmap or series of flashcards that represent the three sleeping disorders starting with insomnia. (A01)