Brain wave frequency and amplitude This brief animation illustrates the EEG patterns of the different stages of sleep, including NREM and REM sleep. http://www.youtube.com/watch?v=u WYwMnMMEoU&feature=related
How much time is spent in NREM 1-4 is variable across the lifespan and from individual to individual From birth to adolescents the amount of time spent asleep decreases rapidly. Once in adulthood the rate becomes relatively stable. See figure 3.17 pg 150
Infants = 16 hours of sleep per day on average Toddlers = 12-13 hours Childhood -> adolescents = 11 hours (2 spent in REM) Adulthood = 6-7 hours about 1/3 in REM 60+ = sleep becomes lighter with less time spent in Stage 3 or 4 NREM
http://www.youtube.com/watch?v=oik olarevck Here a psychologist from Chicago discusses the physical nature of dreaming, including its correlation with REM sleep, REM rebound and sleep paralysis. He also briefly discusses Freudian interpretations of dreams.
Circadian Rhythms (biological changes occurring on a 24-hour cycle) Our energy level, mood, learning, and alertness all vary throughout the day. Sections of the hypothalamus called the suprachiasmatic nucleus (SCN) and the pineal gland regulate these changes.
Disrupted circadian rhythms, through shift work, jet lag, and sleep deprivation may cause mood alterations, reduced concentration and motivation, increased irritability, lapses in attention, and reduced motor skills.
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Factors that effect adolescent sleep 1. Environmental Cues -> sunlight, alarm clocks etc 2. Physiological Changes -> sleep wake cycle shift - associated with puberty, hormonal changes normally make the body clock shift by 2 hours (approx) and therefore make the adolescent sleepier later at night. 3. Social Factors Parties, Academics, Employment 4. Psychological Factors Relationship troubles, real or perceived stress
The sleep-wake cycle shift delays the onset of sleep by two hours, which results in the adolescent requiring two more hours of sleep upon waking If the adolescent has work or school and needs to be awake early in the morning, it is likely that there hasn t been sufficient sleep. Therefore over time this effects the adolescent and a sleep debt develops, (sleep that accrues and needs to be made up for)
Read Boxes 3.7 & 3.8
Survival theory proposes that sleep conserves energy and protects organisms from danger. Predators sleep more than their prey, but smaller animals who can hide easily also sleep more. Restoration theory proposes that NREM sleep restores and repairs the body, while REM sleep restores the brain and is involved in processes of memory and learning. What are the criticisms of each theory?
Restoration theories suggest that the function of sleep is to repair and restore the brain and body. If this did not happen, then the functioning of the brain and body would gradually break down. Within this general area, two theorists have made important theoretical contributions.
Oswald (1980) suggests that different types of sleep are necessary for restoring different biological functions. Rapid Eye Movement (REM) sleep is necessary for brain growth, repair and reorganisation. During REM sleep patterns of brain activity change to allow this to happen. Slow Wave Sleep (SWS) is necessary for bodily growth and repair. During SWS, growth hormone is released, which is important for protein synthesis.
Horne (1988) extends Oswald s theory. He suggests that sleep is divided into core sleep (REM and SWS) and optional sleep. He suggests that brain restoration and repair take place during core sleep. Bodily restoration occurs during optional sleep, but can also occur at other times (e.g. during periods of relaxed wakefulness).
The restoration theory makes the following predictions: During periods when the brain is growing or undergoing reorganisation, there will be an increase in the amount of REM sleep a person has. See pg 161 figure 3.24 Sleep will increase when the body is growing or undergoing repair. If a person is deprived of sleep for a significant period, they will attempt to catch up on the sleep they have lost. Sleep deprivation will cause deficits in psychological functioning and have a negative effect on bodily processes.
REM Rebound refers to catching up on REM sleep by spending more time in REM than usual, in order to make up for lost REM.
An evolutionary theory of sleep which states that organisms sleep during the time of the day they are most vulnerable to predators. In short, the function of sleep is to protect the organism from death and as a result prolong the survival of the entire species. This is supported by the extended sleeping patterns of animals such as horses that don t have many natural predators.
In relation to humans, obviously we need light to find food and hunt, and as our night vision is not strong, we are susceptible to predators at night. Therefore we sleep when it s dark. Weakness of Survival Theory- If sleep is an ASC and we lose awareness, how can this possible be beneficial to survivial.
Complete LA 3.5 and 3.9
Simply, it means going without. Two kinds partial and total Partial = no having as much as is usually required Total = no sleep at all
Effects = lack of energy, increased irritability, loss of focus, impaired motor skills. Prolonged partial sleep deprivation can result in lower performance on cognitive tasks such as word problems and spatial reasoning activities. Memory processes are also often effected.
Studies on rats show that total sleep deprivation can result in a loss of body weight and a diminishment of the immune system. Other effects can include both visual and auditory hallucinations, due to excessive amounts of neurotransmitters that are secreted to enable the individual to stay awake.
TSD is hard to measure, as it is unethical to conduct a study that deprives people of basic human rights such as sleep for extended periods of time. Therefore convenience sampling is often used and insomniacs are readily used as participants in a case study. During these case studies it has been found that individuals who have experienced total sleep deprivation suffer from microsleeps a very short period of drowsiness that occurs whilst asleep.
Sleep deprivation Sleep deprivation has varying emotional, cognitive and physiological effects. How do these effects differ if the subject has had partial sleep deprivation or prolonged sleep deprivation? What is REM rebound and sleep debt and why do they occur? Source: Digital Vision
Describe the general sleep pattern over a lifespan.
Question 1: The procedure for conducting sleep observations in a sleep laboratory is known as? Answer: Polysomnography Question 2: What device detects, amplifies and records electrical activity of the muscles? Answer: EMG Question 3: What percentage of an adults sleep is comprised of REM? Answer: 20% Question 4: During which stage of NREM do sleep spindles occur? Answer: Stage 2 Question 5: Identify the hormone that makes us feel sleepy at night time. Answer: Melotonin Question 6: Identify the term that describes our 24 hour biological clock. Answer: Circadian rhythm Question 7: According to the theory of sleep, sleep conserves energy and protects organisms from predators. Answer: Survival Question 8: Identify the long term effects of prolonged periods of sleep deprivation on humans. Answer: None
1. All holiday homework must be submitted by P5 Friday 2 nd March 2. Chapter 2 summary notes 3. Chart effects of sleep deprivation 4. You tube & worksheet 5. Chapter 3 summary notes 6. Chapter 3 1 page topic summary & make up and answer a question on each topic 7. LA. 3.5, 3.9, 3.10, 3.14 8. Re-do research methods test in your notes