4. Individual Differences in Sleep Flashcards
1
Q
the components of sleep regulation
A
- SCN = circadian clock - tells us when top sleep and wake (body temp, hormone secretion…)
- sleep homeostasis = sleep pressure
- Pineal = melatonin (inhibited by day light)
- if any are disrupted, sleep is impacted
2
Q
sleep across the life span
A
Carskadon & Rechtschaffen (2005)
- sleep latency = time it takes to fall asleep
- doesnt really change across the lifespan (slightly longer between 5-10)
- wake after sleep onset (WASO) - 45+ WASO increases (bladder, pain, medical problems)
- REM = children 0-5 spend most time in REM, dropping slightly in adulthood
- SWS = decreases as you get older - very large amounts as children (perhaps development related)
- hard to initiate and maintain SWS the older you are (link to WASO?)
3
Q
sleep in young children
A
Jenni & Carskadon (2005)
- sleep amount decreases as they get older (physiological and social influences)
- REM decreases, longer 90 minute cycles - becomes more regular
- some naps throughout the day until 3-5yo
4
Q
sleep in newborns
A
- no regular rhythm (circadian cycle, brain and visual system still developing)
- 16/18h of sleep per day/night usually containing 2 cycles each episode
- start cycles through REM with more time spent in it, plus more time in SWS and stage 3
- each cycle lasts 50/60 minutes and are discontinuous lasting 2.5-4h (due to need for food)
5
Q
sleep in first years
A
- circadian rhythm begins to emerge around 2/3 months
- start responding to environmental cues leading to longer sleeps at night
- sleep cycles become more regular
- sleep onset become non-REM
- lots of time in slow wave sleep
- each cycle 50-60 mins
- by 6 months total sleep time increases slightly and continuous sleep increases to 6 hours
- by 12 months infant usually sleeps for 14-15h with most in the evenings taking fewer naps in the day
6
Q
who conducted the study finding out the sleep cycle across the ages up until adolescence?
A
Jenni and Carskadon (2005)
7
Q
daytime vs nighttime sleeping
A
1 month = half/half
4 years = nighttime sleeping only
8
Q
sleep in teenagers
A
- lots of changes in sleep pattern and behaviour
- need 9-10h sleep per night (Carskadon et al., 2003) but don’t get near this due to school hours
- delayed circadian rhythm due to hormones
- Sunday nights sleep is most problematic as they still think its the weekend, so go to bed later than they would on a week night. they then wake up tired = take naps throughout the day
- this means they are not biologically ready to sleep at the right time (build up of adenosine not sufficient) so the body clock becomes delayed
- also a biological predisposition to go to bed late and get up late which sleeping in at weekends makes worse
- teenagers more likely to engage in cognitively stimulating tasks before bed that release blue light which delays body clock even further by blocking melatonin = poor sleep hygiene
9
Q
sleep in adults
A
Newbauer (1999)
- sleep is intermittent
- less SWS
- more and shorter cycles
- more time awake (WASO higher) - elderly sometimes take naps
10
Q
teenagers and performance
A
Kelley et al (2015)
- performance at different kinds of time of day
- tested at 10am and 2 pm
- study only conducted once in one school
- given word pairs test
results show that students performed significantly better when tested at 2pm
- changes of school times? would also need to change the timings of other societal things (work times)
11
Q
melatonin change across the lifespan
A
Karasek and Winczyk (2006)
- young children significantly higher than adults (5-10yo)
- older adults show very low levels of melatonin
- the increase in melatonin throughout the day also decreases
12
Q
Chronotype preference across the lifespan
A
definitely evening = 16-30 moderate evening = 31-41 intermediate = 42-58 moderate morning = 59-69 definitely morning = 70-86
- teenagers more likely to be evening types (delayed circadian rhythms)
- older adults more likely to be morning types (wake/sleep early)
- in general, more people will fall into intermediate level
- Roenneberg et al (2007)
13
Q
R?oenneberg et al (2007)
A
- higher the score, the more likely you were to be an evening person
- found that young people were more likely to be evening and older people more likely to be morning people
- men tend to go to bed later in the early years, women in their older years (50+)
- intermediate both males and females same
- has a genetic basic (clock genes)
14
Q
clock genes
A
- approximately 18 identified so far
- they work on a molecular feedback loop
- genes are turned on and produce a message which produces a selection of clock proteins
- the created proteins then turn off the gene
- the proteins are then degraded and the process starts again
- cycle of protein production and degradation gives signal to circadian rhythm which could be different for each individual
- ‘period 3’ gene has been linked to this
- morningness/eveningness = 50% genetic basis
- morning types are less affected by sleep deprivation (with increased SWS at beginning of night)
15
Q
period 3 gene
A
- homozygous PER3 5/5 = morning type
- homozygous PER3 4/4 = evening type
- homozygous = different forms, heterozygous is still unknown
