January & February 2015

PlanThis term – pack completion should mainly be done outside lessons.

• 6th and 9th nature of sleep• 13th lifespan changes• 16th H group SLC, G group room 62• 20th complete preparation, begin presentations• 23rd complete presentations• 27th to half term, sleep disorders• 3rd February subject review (L-Z), 6th sleep disorders and review• 10th 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 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 16.30 to sea lions)

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)

Age Average no. of hours of sleep

Newborn 18

1 to 12 months 14-18

1 to 3 years 12-15

3 to 5 years 11-13

5 to 12 years 9-11

Adolescents 9-10

Adults 7-8

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 https://books.google.co.uk/books?

id=tP6ZAgAAQBAJ&pg=PA24&lpg=PA24&dq=hours+of+sleep+lifespan+table&source=bl&ots=jEssP781YO&sig=nDxYhn375QaMxlk8zfh2FY7Uzz0&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

• http://psychology.about.com/od/statesofconsciousness/p/TheoriesofSleep.htm (includes another explanation - information consolidation but you do not need to know this)

• Blind fish http://www.wired.com/2011/05/blind-fish-in-dark-caves-shed-light-on-the-evolution-of-sleep/

• http://www.philipallan.co.uk/pdfs/txtpsya209.pdf 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 https://www.youtube.com/watch?v=LWULB9Aoopc

Disorders of sleep

• DSM IV (to V)

• Some sleeping disorders are classified as psychological abnormalities including: primary insomnia, sleepwalking and narcolepsy.

Insomnia

• 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)