Sleep

Question 1

Define: sleep

Answer 1

A regularly occurring ASC that typically occurs naturally and is primarily characterised by a loss of conscious awareness.

Question 2

In what ways can sleep be deliberately induced?

Answer 2

By drugs (eg. medication) and alcohol

Question 3

Define: sleep cycle

Answer 3

A period of NREM sleep followed by a period of REM sleep.

Question 4

How long is a typical sleep cycle?

Answer 4

80-120mins

Question 5

How many sleep cycles are usually experienced during an 8 hour night?

Answer 5

4-5

Question 6

Describe the patterns of NREM and REM sleep across the night.

Answer 6

NREM sleep gets shorter, and less time is spent in stage 3 and 4 (especially after the first 2 cycles)
REM sleep gets longer.

Question 7

What proportion of sleep is NREM/REM?

Answer 7

80%/20%

Question 8

How light/deep is stage one NREM sleep?

Answer 8

Very light

Question 9

Can a person be woken easily in stage one NREM sleep?

Answer 9

Yes; the might not believe they had fallen asleep

Question 10

How long does a person spend in stage one NREM sleep?

Answer 10

5-10mins

Question 11

Describe the EEG, EOG and EMG patterns in stage one NREM sleep.

Answer 11

EEG: alpha waves are being replaced by theta waves
EOG: slow, gentle rolling eye movements
EMG: moderate to low activity; may experience hypnic jerks

Question 12

The hypnagogic state is experienced in stage one NREM sleep. Define: hynpagogic state

Answer 12

the transition between being awake and asleep, characterised by vivid images including falling and slipping

Question 13

Hypnic jerks are experienced in stage one NREM sleep. Define: hypnic jerks

Answer 13

Involuntary muscle spasms as a result of the muscles relaxing.

Question 14

How light/deep is stage two NREM sleep?

Answer 14

Light; we are truly asleep.

Question 15

Can a person be woken easily in stage two NREM sleep?

Answer 15

Somehwat, not as easily as stage one.

The brain may respond to external stimuli (represented by K-complexes) but may not wake up.

Question 16

Define: K complex

Answer 16

Bursts of low frequency and high amplitude waves in response to arousing (internal or external) stimuli.

Question 17

Can K complexes follow a sleep spindle?

Answer 17

Yes

Question 18

Define: sleep spindle

Answer 18

A one second, brief burst of high frequency brain activity.

Question 19

What do sleep spindles indicate?

Answer 19

That the person is truly asleep.

Question 20

How long does a person spend in stage 2 NREM sleep?

Answer 20

10-20 mins, but decreasing throughout the night

Question 21

Describe the EEG, EOG and EMG patterns in stage two NREM sleep.

Answer 21

EEG: theta
EOG: rare activity
EMG: moderate-low activity

Question 22

How light/deep is stage three NREM sleep?

Answer 22

Moderately deep.

Question 23

Can a person be woken easily in stage three NREM sleep?

Answer 23

Difficult to awaken, and if so they are groggy and disoriented
Also very unresponsive to outside world during sleep.

Question 24

How long does a person spend in stage 3 NREM sleep?

Answer 24

10 minutes

Question 25

Describe the EEG, EOG and EMG patterns in stage three NREM sleep.

Answer 25

EEG: 20-50% delta; the rest are theta EOG: rare activity EMG: low activity

Question 26

How light/deep is stage four NREM sleep?

Answer 26

Very deep.

Question 27

How long is spent in stage four NREM sleep?

Answer 27

20 mins but this reduces.

Question 28

Can a person be woken easily during stage four NREM sleep?

Answer 28

Not at all. May take up to 10 minutes to orient themselves, and have difficulty remembering sleep events.

Question 29

In stage 4 NREM sleep, sleep inertia is experienced. Define: sleep inerita

Answer 29

Mental lag occurring after awakening from very deep sleep.

Question 30

Describe the EEG, EOG and EMG patterns in stage four NREM sleep

Answer 30

EEG: over 50% delta EOG: Rare activity EMG: low activity

Question 31

What is stage 3 and 4 NREM sleep referred to as collectively?

Answer 31

Slow wave sleep.

Question 32

What is the key characteristic of REM sleep?

Answer 32

Eyeballs rapidly move beneath closed eyelids.

Question 33

How light/deep is REM sleep?

Answer 33

Relatively light

Question 34

How much of our dreams occur in REM sleep?

Answer 34

Around 85%

Question 35

How long do we spend in REM sleep?

Answer 35

10 mins, increasing to up to an hour.

Question 36

Can a person be woken easily during REM sleep?

Answer 36

Yes. Furthermore, you are likely to remember what you dreamed about.

Question 37

Describe the EEG, EOG and EMG patters in REM sleep.

Answer 37

EEG: beta-like waves EOG: bursts of rapid eye movement EMG: barely any muscle activity

Question 38

Muscle atonia is experienced during REM sleep (with the exception of a few small twitches). Define: muscle atonia

Answer 38

Relaxation of skeletal muscles to the point of being paralysed.

Question 39

Why is REM sleep referred to as paradoxical sleep?

Answer 39

The body appears calm externally but internally, the brain and body are active.

Question 40

What is the state that occurs between sleeping and waking up?

Answer 40

Hypnopompic state.

Question 41

What are the characteristics of sleep as an altered state of consciousness?

Answer 41

Level of awareness - not awake, nor unconscious Fewer content limitations Controlled and automatic processes are impossible Perceptual and Cognitive Distortions More or less emotional awareness Less self control Distorted time orientation