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PSYCHOLOGY…read more

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· Ultradian ­ occurs more than once a day
examples include eating, body temperature,
heartbeat and dream cycles
· Circadian ­ occurs approximately every 24
hours such as the sleep wake cycle
· Infradian- occurs more than every 24 hours such
as menstruation cycle, SAD and hibernation…read more

Slide 3

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The dream cycle was tested by monitoring people in their
sleep. Electrodes where attached to measure brain activity.
EEG measures brain activity, EMG measures muscle activity
and EOG measures eye muscle activity.
Electrical activity changed at different stages of sleep:
Stage one is very similar to when a person is awake, by
stage three the person is moving around a lot however
during REM the person is in deep sleep so are very still.…read more

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· There are five cycles of sleep which each last 90
minutes this is called break-rest activity cycle.
Each cycle is split into five stages. The five
cycles work in a loop.
· Can dream for up to 45 minutes as we dream for
longer as the cycle progresses. A person has an
average of 5 dreams a night
· If woken up in a certain stage a person will react
differently for example being very tired, or easily
being able to remember a dream.…read more

Slide 5

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1. Lasts around 15 minutes. The body relaxes and the person becomes drowsy. There is a
slow rolling eye movement and a reduction in muscle tension. Heart rate and
temperature also fall. The person will be in a hypnotic state where hallucinations may
occur such as the feeling of falling. Alpha waves are measured
2. Lasts around 20 minutes, this is where the k-complex could occur where a person feels
that their body is jumping. There is little eye movement and the muscles are relaxed. The
person is easily awoken. Theta waves detected.
3. Lasts around 15 minutes, there is little eye movements and the muscles are relaxed.
Delta waves are detected.
4. Lasts around 30 minutes there is little activity in muscle or eye movement. The person is
in a deep sleep so it is hard for them to wake up. Body temperature, heart rate and blood
temperature drop to their lowest points. Growth hormones are also secreted. Stage of
sleep walking, talking and night terrors occur. Delta waves are detected
5. Lasts 10 minutes at first but cycle increases to up to 1 hour in the 4th and 5th cycle of
sleep. The person is in a relaxed waking state. High levels of brain activity is associated
with breathing. This is often called the REM stage. The brain is active but the body is
paralysed. This is to stop the person from acting out their dreams. This is the hardest
stage to wake from. Beta waves are detected.…read more

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Nine sleeping participants where studied as
they spent 61 nights in a laboratory. The brain
activity was recorded. Each participant was
woken up during different stage of sleep. The
patient was asked to report their experiences
and emotions. People who where awakened in
the REM stage reported dreams 80-90% of the
time. The dreams where recorded in great
detail. Only 7% of people woken from NREM
sleep led to dream recall. In deep sleep people
reported confusion and thought they had been
dreaming but could not report their dream.…read more

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very pretty and informative. Thank you for sharing 



Really helpful with revision, thanks 



So helpful, merci beaucoup!!!!

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