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Explanations of other
sleep disorders
Topic 9…read more

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Explanations of Narcolepsy AO1
REM HLA Hypocretin
· Narcolepsy could be due to a · Hypocretin regulates sleep
· A symptom of narcolepsy mutated immune system
is a loss of muscle tone - and wakefulness
this is similar to what · It does this by interacting
Honda et al (1983)
happens in REM · Higher frequency of a with systems in the
type of HLA in hypothalamus which
· Narcoleptics get narcoleptics regulate emotion and
intrusions of REM in the · HLA is found on white
day through homeostasis
blood cells and · Narcoleptics have low
hallucinations coordinates immune
system resonses levels of hypocretin
· At night narcoleptics have · 90% of narcoleptics with · Hypocretin and narcolepsy
abnormal sleep cataplexy (loss of muscle must be linked
tone) have HLA
· The cause of narcolepsy However it's not clear how it leads
could therefore be a to narcolepsy
malfunction in the REM
regulator…read more

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REM explanation AO2
Vogel (1960)
· Observed REM in narcoleptic patients and saw that
narcoleptic patients experience REM straight away
Siegel (1999)
Siegel recorded neuron activity in narcoleptic dogs and
showed that cataplexy (loss of muscle tone) occurs during
REM brain cell activity
This supports the REM explanation because it suggests that the REM regulator has
malfunctions and that cataplexy truly does occur during REM.
General research however hasn't been convincing.…read more

Slide 4

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HLA explanation AO2
The HLA variant isn't found in all narcoleptics
Mignot et al (1997)
The HLA variant is common in the general population
This discredits the HLA explanation because it suggests that HLA cannot be a cause
of narcolepsy as it's not found with all sufferers and is also found in non sufferers.…read more

Slide 5

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Hypocretin explanation AO2
Nishino (2000)
· Evidence originally came from studying narcoleptic dogs
· However the findings are supported by a human study that shows that narcoleptics
have a lower than normal level of hypocretin
It is likely that low hypocretin levels are due to brain injury, infection, diet,
stress or due to an autoimmune system attack (where the immune system
turns on itself)
Mignot (2001)
· HLA and hypocretin is linked
· This is because the HLA mutation affects the immune systems response and makes
autoimmune conditions more likely
· This may therefore result in a reduced level of hypocretin
This supports the hypocretin explanation because it suggests that low hypocretin
levels do exist in narcoleptics and it also explains how HLA affects hypocretin levels…read more

Slide 6

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Explanations of Sleep Walking AO1
Incomplete Risk factors Why Children
Arousal · Some factors increase the
likelihood of sleep walking
· Oliviero (2008) tried to
explain why sleep walking is
· Sleep deprivation
· Sleep walking is when · High temperature
more common in childhood
someone is partly awake · Hormonal changes · The system that normally
and partly in SWS sleep inhibits the motor activity in
· Alcohol
· Recordings of brain · stress SWS isn't fully developed in
However as these risk factors only some children or adults
activity have shown that
whilst sleep walkers trigger sleep walking in certain · Oliviero did research and
experience SWS and B individuals it shows that some
people may simply be more found that sleepwalkers has
brain waves (occur when immaturity in relevant
awake) vulnerable to sleep walking
neural circuits
· Therefore, sleep waking
occurs when someone's
deep sleep is awakened
but the brain isn't fully
aroused…read more

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