Sleep

Question 1

1) What is the behavioural definition of sleep?

Answer 1

Sleep is a reversible unconsciousness state, lack of mobility and increased arousal threshold.

Question 2

2) During what part of the night is slow wave sleep seen?

Answer 2

It is more prominent during the first third of the night

Question 3

3) When does the first REM period typically occur?

Answer 3

Usually at the end of the first sleep cycle -approximately 70-120 minutes after sleep onset -(depending on age and other factors)

Question 4

4) What happens to REM periods across the course of the night?

Answer 4

REM periods progressively increase in length

Question 5

5) What % of total sleep in adults is composed on NREM?

Answer 5

75-80% of sleep time

Question 6

6) What % of sleep in adults is composed of REM sleep?

Answer 6

20-25% of sleep time

Question 7

7) What happens to the distribution of the stages of sleep in the elderly population?

Answer 7

• decrease in slow wave sleep - lighter NREM sleep - more fragmented night-time sleep, more time spent awake

Question 8

8) What are zietgebers?

Answer 8

Environmental variables that are capable of entraining circadian rhythm. Most potent zietberger is exposure to bright daylight. Weaker zietbergers are exercise, social stimuli, temperature and feeding.

Question 9

9) What is ‘microsleep’?

Answer 9

Microsleep is a transient physiologic sleep (3-14 seconds of EEG pattern change from wakefulness to stage 1) with or without rolling eye movements or behavioural sleep (drooping and nodding of head).

Question 10

10) What neurotransmitters are associated with the REM-on state?

Answer 10

Cholinergic system-releases neurotransmitter acetylcholine.

Question 11

11) What neurotransmitters are associated with the REM-off state?

Answer 11

The adrenergic system, including norepinephrine and serotonin. Also histamine.

Question 12

12) Where is the suprachiasmatic (SCN) nuclei located? Describe its role in circadian rhythms

Answer 12

Located in the anterior hypothalamus dorsal to optic chiasm. Retinohypothalamic tract sends input directly to the SCN to help modulate circadian rhythms

Question 13

3. Summarise the neurotransmitters that are thought to be involved in wakefulness and sleep and their site of release.

Answer 13

Question 14

14. What are some wake-promoting factors found in cerebrospinal fluid (CSF) and blood?

Answer 14

CSF: substance P, cortico-tropin releasing factor, thyrotropin-releasing factor, vasoactive intestinal peptide, and neurotensin. Blood: epinephrine, cortisol, histamine, corticotropin, thyrotropin.

Question 15

15. What are some factors in the CSF and the blood that are thought to promote sleep?

Answer 15

CSF: enkephalin, endorphin, dynorphin, alpha-melanocyte-stimulating hormone, growth hormone-releasing factor, prostaglandin D2, and interleukin. Blood: Insulin, cholescystokinin, and delta sleep inducing peptide.

Question 16

1. What is a polysomnogram?

Answer 16

Test consisting of EEG, EOG, EMG, ECG and respiratory, blood oxygen saturation and audiovisual data.

Question 17

2. What sleep disorders require polysomnograpy for diagnosis?

Answer 17

Sleep-related breathing disorders- sleep apnea.

Question 18

3. What are the indicators of polysomnography in patients with insomnia?

Answer 18

PSG is indicated when symptoms of insomnia are not adequately diagnosed by obtaining a sleep history, assessing sleep hygiene, and reviewing sleep diaries.

Question 19

4. When is polysomnography indicated in patients with parasomnias?

Answer 19

PSG and extended EEG channels is indicated when sleep disruption is thought to be seizure related. PSG indicated in evaluating sleep-related behaviours that are violent & unusual.

Question 20

1) Define dreaming.

Answer 20

Internally generated perceptual experiences during sleep and appears at that time as reality.

Question 21

Ho: Function of REM sleep:

Answer 21

unlearning of unnecessary information - release of pent-up emotions or anxieties that develop during waking hours

Question 22

2) Since dreaming takes place during sleep, how can it be studied objectively?

Answer 22

REM associated with dreams • Neurones of the visual system fire intensely during REM sleep - likely because visual scenes in dreams • Most people can remember their dreams if awakened during REM • EEG of REM sleep resemble waking EEG • Identify states of REM: - EEG shows low voltage, high frequency activity indicating high brain activation - EMG shows drop in muscle tone & - EOG: presence of rapid saccadic eye movement • Reports captured on tape for later analysis

Question 23

3) Is a sleep walker acting out his or her dreams?

Answer 23

No, sleepwalkers are aroused early from first or second cycle of non-REM sleep before dreaming has taken place

Question 24

4) Do brain imaging studies help the understanding of dreaming?

Answer 24

Identifies brain areas involved. PET (Positron Emission Tomography): - reveal a higher level of activity in the amygdala & paralimbic system during REM sleep - this implicates the involvement of long term memory system

Question 25

5) Discuss your understanding of a nightmare?

Answer 25

* a nightmare is a dream that is frightening enough to awaken the sleeper * common in children * increase in frequency after stressful events and are a hallmark symptom of posttraumatic stress disorder * Can be treated by application of cognitive behavioural therapy

Question 26

6) How does a night terror differ from a nightmare?

Answer 26

* Night terror is associated with non-REM while a nightmare occurs during REM sleep. * Night terror occurs mainly in young children, within firsthour of sleep before first REM period. * In night terror there is a glazed eye, screaming and an increased heart rate * Dream content is not reported in nightmare and there is no recall of the episode on awakening * Run in families with the prevalence doubling when both parents are affected as children * Night terrors reduce in frequency during adolescence and are disorders of arousal and not dreams

Question 27

Physiological functions of the body change according to daily cycles known as: a) biological rhythms b) circadian rhythms c) daily rhythms d) nocturnal rhythms

Answer 27

) circadian rhythms

Question 28

During non-REM sleep your EEG pattern is: a) low voltage, fast b) low voltage, slow c) high voltage, slow d) high voltage, fast

Answer 28

c) high voltage, slow

Question 29

REM accounts for most of our sleep. a) true b) false

Answer 29

f

Question 30

What is the primary zeitberger for mammals? a) light-dark b) gravity c) temperature d) time

Answer 30

light-dark

Question 31

What do people with REM sleep disorder do? a) rarely sleep b) sleep too much c) act out their dreams d) do not experience REM sleep

Answer 31

c) act out their dreams

Question 32

A sudden muscular paralysis while consciousness is maintained is known as _________. a) narcolepsy b) atony c) aphoria d) cataplexy

Answer 32

d) cataplexy

Question 33

Somnabulism is also known as: a) night terrors b) nightmares c) sleepwalking d) dreams

Answer 33

) sleepwalking

Question 34

. Somniloquy is also known as: a) sleep walking b) sleep talking c) dreams d) nightmare

Answer 34

b) sleep talking

Question 35

. Night terrors can often be a symptom of a psychiatric disorder. a) true b) false

Answer 35

) false

Question 36

Of the four of five REM periods each night, in which do dreams occur? a) 1 b) 2 & 3 c) 4 & 5 d) all

Answer 36

d) all