5. Sleep and Wakefulness

Question 1

What is sleep?

Answer 1

• natural mandatory cyclic behavioural state
• Low-No awareness, low-no arousal
• Self-regulated and easily reversible to wakefulness

Question 2

Name different levels of wakefulness…

Answer 2

Maximal alertness  wakefulness  sleep  coma

Question 3

Name characteristics of REM sleep…

Answer 3

• rapid eye movement
• muscle twitches
• dreams common
• penile erection common
• fluctuating vital signs
• ## decreased muscle tone

Question 4

EEG: compare REM with NREM sleep.

Answer 4

REM: low voltage, beta waves
NREM: spindles, v-waves, k-complexes, slow waves
theta, delta waves

Question 5

Name characteristics of NREM sleep.

Answer 5

• slow eye movement
• muscle relaxation
• stable vital signs
• some tone in postural muscle

Question 6

Adults: percentage REM/NREM sleep

Answer 6

REM 25%

NREM 75%

Question 7

Children: percentage REM/NREM sleep

Answer 7

REM 50%

NREM 50%

Question 8

Compare the different sleep stages re. different kinds of waves

Answer 8

wakefulness: alpha, beta waves
REM: beta rhythms
Stage I: theta rhythms
Stage II: sleep spindle, k-complex
Stage III: delta
Stage IV: delta rhythms

Question 9

Why do we need sleep?

Answer 9

• Every vertebrate animal sleeps
• Slow wave (NREM) vs rapid wave sleep (REM) Slow wave sleep (NREM): allows the brain to rest
• Learning & memory
• Brain development

Question 10

NREM sleep: functions

Answer 10

• Reduction in metabolism and blood flow (75%)
• Brain is at rest
• Oxidative stress

Question 11

REM sleep: functions

Answer 11

• High frequency waves
• Intense physiological activation
• Amount of REM sleep decreases over time (brain development; learning and memory)

Question 12

Long term memory can be divided into…

Answer 12

declarative knowledge

nondeclarative knowledge

Question 13

Name two types of declarative knowledge.

Answer 13

EPISODIC: remembering first day at school
SEMANTIC: knowing capital of france

Question 14

Name three types of nondeclarative knowledge.

Answer 14

SKILL LEARNING: knowing how to cycle
PRIMING: being more likely to use a word you’ve recently heard
CONDITIONING: salivating when you smell favourite food

Question 15

Episodic and semantic knowledge is stored in…

Answer 15

the cortex

Question 16

Skill-learning knowledge is stored in …

Answer 16

• basal ganglia
• cerebellum
• motor cortex

Question 17

Priming knowledge is stored in…

Answer 17

CORTEX

Question 18

Conditioning knowledge is stored in…

Answer 18

the CEREBELLUM

Question 19

Nissen et al. 2006

Answer 19

Mirror-tracing task

Less improvement in insomniacs

Question 20

How is sleep regulated?

Answer 20

homeostatic regulation

Question 21

Degradation of adenosine happens mainly during ________ sleep.

Answer 21

NREM

Question 22

Sleep/waking regulation can be described as a ______________.

Answer 22

flip-flop circuit

Question 23

Describe the sleep-waking flip-flop circuit.

Answer 23

FLIPFLOP ON:
- arousal centres active
- VLPA inhibited
= alert waking state

FLIPFLOP OFF:
- arousal centres inhibited
- VLPA activated
= slow-wave sleep

Question 24

Sleep/waking Flipflop: where are the arousal centres located?

Answer 24

• brainstem

- forebrain

Question 25

Sleep/waking Flipflop: what is activated by the arousal centres?

Answer 25

Production & secretion of... NASH - Norepinephrine - Acetylcholine - Serotonin - Histamine

Question 26

Why do we grow tired?

Answer 26

prolonged wakefulness --> prolonged metabolic activity of neuron in brain --> accumulation of adenosine --> activates VLPA --> arousal centres inhibited - -> decrease in NASH - -> tiredness, need for sleep

Question 27

What role do hunger/satiety signals play in the sleep/wake circuit?

Answer 27

hunger --> activates LH in orexinergic neurons --> activates arousal centres satiety --> inhibits LH --> arousal centres not activated

Question 28

Short term effects of caffeine on the physiology?

Answer 28

Increase: heartrate, neuronal activity Decrease: sleepiness, vasodilation

Question 29

How does caffeine prevent us from being sleepy?

Answer 29

- competes with adenosine at cell receptor - when caffeine reaches receptor, adenosine can not be activated - -> no sleepy signal to body

Question 30

Name the three main criteria of Caffeine Use Disorder.

Answer 30

(1) a persistent desire or unsuccessful efforts to control caffeine use; (2) continued caffeine use, despite knowledge of having a persistent or recurrent physical or psychological problem that is likely to have been caused or exacerbated by caffeine; (3) withdrawal

Question 31

name 4 types of adenosine receptors.

Answer 31

Adenosine A1 receptor Adenosine A2A receptor Adenosine A2B receptor Adenosine A3 receptor

Question 32

where is the Adenosine A1 receptor localized?

Answer 32

broad distribution high in - nerves - adipose tissue - heart - kidney

Question 33

where is the Adenosine A2A receptor localized?

Answer 33

broad distribution very high in: - basal ganglia high in: - nerves - blood vessels - immune cells

Question 34

where is the Adenosine A2B receptor localized?

Answer 34

broad distribution | low abundance

Question 35

where is the Adenosine A3 receptor localized?

Answer 35

restricted distribution, varying across species | - high in mast cells