Sleep

Question 1

What are the behavioural criteria for sleep?

Answer 1

Stereotypic or species-specific posture
Minimal movement
Reduced responsiveness to external stimuli
Reversible with stimulation - unlike coma, anaesthesia or death

Question 2

Physiological critera for sleep

Answer 2

Electroencephalogramm (EEG)
Electrooculogramm
Electromyogramm

Question 3

What are the stages of sleep?

Answer 3

AWAKE:
Activity in EEG, EOG, EMG

STAGE 1+2 (NREM)
Non-REM sleep

STAGE 3+4 (NREM)

STAGE 5 (REM)
EOG - tracks muscle movement to do with eye
EEG (tracks rapid activity) - looks quite similar to awake stage
More likely to report dreaming
Heart rate goes up

Slide 10 [pic]

NOTE: go through multiple sleep cycles throughout sleep

Question 4

Describe a single sleep cycle

Answer 4

Slowing until we reach REM sleep

Slide 11 [pic]

Question 5

CLOZE

The Reticular Activating System controls consciousness

Answer 5

…

Slide 15 [pic]
Without this, consciousness does not exist

Question 6

How is the sleep/wake cycle controlled?

Answer 6

Lateral hypothalamus promotes wakefulness (neurotransmitter important for system =orexin/hypocretin)

Ventrolateral preoptic nucleus (anterior hypothalamus) promotes sleep

Slide 17 [pic]

Suprachiasmatic nucleus synchronises sleep with falling light level

NOTE: melatonin can be used for e.g. jet lag = melatonin goes up to make you sleepy

Question 7

What are the effects of sleep deprivation?

Answer 7

Slide 22

Question 8

After sleep loss, what happens to the regulation of sleep?

Answer 8

Reduced latency to sleep onset
Increase of slow wave sleep (NREM)
Increase of REM sleep (after selective REM sleep deprivation)

Question 9

What are the functions of sleep?

Answer 9

restoration and recovery - but active individuals do not sleep more
Energy conservation (10% drop in basal metabolic rate) - but lying still is just as effective
Predator avoidance - but why is sleep so complex?
Specific brain functions - memory consolidation etc etc

Question 10

When do dreams occur?

Answer 10

Can occur in REM and NREM sleep
Most frequent in REM sleep
More easily recalled in REM sleep

Question 11

TRUE OR FALSE:

Brain activity in the limbic system is higher than in the frontal lobe during dreams

Answer 11

TRUE

Question 12

What are the functions of dreams?

Answer 12

Safety valve for antisocial emotions
Disposal of unwanted memories
Memory consolidation

Question 13

What is insomnia?

Answer 13

Trouble sleeping
High prevalence
Most cases transient

Question 14

What arethe cuases of chronic insomnia?

Answer 14

Physiological (e.g. sleep apnea, chronic pain)
Brain dysfunction (e.g. depression, fatal familial insomnia, night working)

Question 15

What are the treatments of insomnia?

Answer 15

Sleep hygiene
Hypnotics (most enhance GABAergic circuits)
Sleep CBT

Question 16

What is sleep hygiene?

Answer 16

Establishing fixed times for going to bed/waking up
Creating a relaxing bedtime routine
Only going to bed when you feel tired
Maintaining a comfortable sleeping environment
Not napping during the day
Avoiding caffeine, nicotine and alcohol late at night
Avoiding eating a heavy meal late at night
Don’t use back-lit devices shortly before going to bed

Question 17

What is hypersomnia?

Answer 17

Excessive daytime sleepiness

Question 18

What are the primary causes of hypersomnia?

Answer 18

Narcolepsy
Idiopathic hypersomnolence
Post-traumatic brain injury

Question 19

What are the secondary causes of hypersomnia?

Answer 19

Slide 33

Question 20

What is narcolepsy?

Answer 20

Falling asleep repeatedly during the day and disturbed sleep during the night
Cataplexy (sudden, brief loss of voluntary muscle tone, often triggered by strong emotions e.g. laughter)
Dysfunction of control of REM sleep
Orexin/hypocretin deficiency

Question 21

What are the effects of shift work on sleep

Answer 21

Night working = physiological processes become desynchronised
Can lead to sleep disorders, fatigue and an increased risk for some conditions (e.g. obesity, diabetes and cancer)

Question 22

What is consciousness?

Answer 22

The subject experience of the mind and the world around us
That there is “something it is like” to be in the state of the subjective or first-person point of view
The state of being aware of and responsive to one’s surroundings