Consciousness part 2

Question 1

What is sleep?

Answer 1

A naturally (recurring) state - reduced consciousness, suspended sensory activity and paralysis of nearly all muscles at some stages.

Question 2

How many hours of sleep is optimal for human adults?

Answer 2

8 hours

Question 3

What controls our “sleep timing”? What decides when we need to sleep?

Answer 3

Our circadian rhythm.

Question 4

How is the circadian rhythm generated?

Answer 4

The Suprachiasmatic Nucleus (SCN) produces melatonin and controls neuronal and hormonal activities in a 24-hour cycle.

Question 5

What does the Suprachiasmatic Nucleus do?

Answer 5

Determines optimal timing of a correctly
structured and potentially restorative sleep.

Its the bodies inner time keeper.

Question 6

What are 3 functions of sleep?

Answer 6

1. Immune system maintenance
2. Memory consolidation
3. Muscle repair

Question 7

What are 3 effects of sleep deprivation?

Answer 7

1. Cognitive impairment
2. Hallucinations
3. Impaired immune system

Question 8

What are the 2 broad types of sleep stages?

Answer 8

1. Non-rapid eye movement (REM) sleep
   and
2. Rapid eye movement (REM) sleep

Question 9

How many sleep stages do humans have? How long does the full cycle (all stages) last?

Answer 9

There are 5 stages of sleep.

Each cycle of the 5 stages lasts about 90 minutes.

Question 10

At what stage of an 8 hour sleep does the most REM sleep occur?

Answer 10

REM stages occur more frequently near the end of the 8 hours.

Question 11

What is Polysomnography?

Answer 11

The study of sleep.

Question 12

What 3 measurements are used to study sleep (brain, eye, and muscular activity)?

Answer 12

(EEG) - electrical activity in the brain.
(EOG) - eye movements
(EMG) - muscular activity

Question 13

What is the name of the graph that summarises the sleep data?

Answer 13

Hypnogram (look it up)

Question 14

How many Non-REM and REM sleep stages are there?

Answer 14

There are 4 Non-REM sleep stages and 1 REM sleep stage.

Question 15

Describe stage 1 of the sleep cycle. How long does it last?

Answer 15

Stage 1 is the transition for awake to asleep.

Its very brief; it only lasts minutes.

There is no memory of this stage.

Question 16

Describe stage 2 of the sleep cycle. How long does it last? What specific EEG patterns happen during stage 2?

Answer 16

Stage 2 is a light sleep.

It lasts about 20 minutes.

EEG patterns:
1. Sleep spindles
2. K-complexes

Question 17

What are sleep spindles?

Answer 17

A burst of brain activity following a muscle twitch (11 – 16hz).

Question 18

What are K-complexes?

Answer 18

A brief negative high voltage peak of activity.

Question 19

Describe stage 3 of the sleep cycle. How long does it last? What specific EEG patterns happen during stage 3?

Answer 19

Stage 3 is the transition to deep sleep.

It lasts a few minutes.

EEG patterns:
Delta brain waves

Question 20

Which stage of sleep do particular parasomnias occur? What are 3 parasomnias that can occur?

Answer 20

Stage 3.

Parasomnias:
1. Night terrors
2. Sleep-walking
3. Sleep-talking

Question 21

Describe stage 4 of the sleep cycle. How long does it last? What specific EEG patterns happen during stage 4?

Answer 21

Stage 4 is deep sleep.

Hard to awaken.

Muscle/body restoration.

EEG similar to Stage 3, but shows more
delta waves (more than 50%)

Question 22

What are delta brain waves?

Answer 22

A high amplitude brain wave of about .5 – 4 hz (slow wave).

Question 23

Describe stage 5 of the sleep cycle.

Answer 23

Stage 5 is Rapid Eye Movement (REM) sleep.

Final stage in the cycle

Lasts longer and longer during the night.

Characterised by rapid eye movements and rapid low-amplitude EEG.

Descending muscular atonia – paralysis
that protects from self-harm

Question 24

What stage of sleep do most (memorable) dreams occur?

Answer 24

Stage 5 - REM sleep

Question 25

How much time do adults spend in stage 5 sleep?

Answer 25

Adults spend 20-25% of total sleep time in REM sleep.

Question 26

How much time do babies spend in stage 5 sleep?

Answer 26

Babies spend up to 50% of total sleep time in REM sleep.

Question 27

Which sleep stage is the brain most active?

Answer 27

Stage 5 - REM sleep

Brain activity similar to levels when awake.

Question 28

What are 3 physiological changes that occur during REM sleep?

Answer 28

1. Heart rate increases
2. Rapid/irregular breathing
3. Eyes dart: 30 second bursts

Question 29

How are dreams created?

Answer 29

Dreams are stimulated by the pons (brainstem)

Question 30

When do dreams occur?

Answer 30

Generally in REM sleep but also in other stages.

Question 31

What are dreams?

Answer 31

A sequence of images, emotions and thoughts.

Question 32

What is the Freudian interpretation of dreams?

Answer 32

Freudian interpretation:
1. Dreams are the fulfilment of wishes that are socially transgressive
2. Unacceptable feelings
3. Erotic urges/violent urges

Dreams offer a ‘safe’ context to deal with unconscious material.

Question 33

What is the activation-synthesis model?

Answer 33

Proposed by Allen Hobson and Robert McCarley in 1977, the Activation Synthesis Theory suggests that the pons causes random brain activity that the forebrain tries to interpret and “synthesise” into dreams or “stories”.

Question 34

What is simple implication of the activation-synthesis model?

Answer 34

Dreams are a meaningless by-product of a neurobiological process.

Question 35

What are 3 functional processes of dreaming?

Answer 35

1. Process information from your day
2. Information processing and learning
3. Problem-solving