Sleep

Question 1

What does sleep polysomnography measure?

Answer 1

Brain activity EEG, eye movements EOG, muscle activity EMG, and heart activity ECG

Question 2

What does EEG measure?

Answer 2

Measures the potential differences between two points on the scalp

Question 3

Wakefulness EEG

Answer 3

Low amplitude fast rhythms

A relaxed subject with eyes closed is differentiated from sleep by the presence of alpha EEG activity in 50% or more of the time.

Question 4

Stage 1 EEG

Answer 4

Similar to wakefulness, very superficial, small eye movements, slow, slightly higher amplitude EEG.

Alpha activity 50% or less of the time

Question 5

Stage 2 EEG

Answer 5

Spindles and K complexes:

Characteristics include sleep spindles and K-complexes occurring on a low-voltage, mixed-frequency background EEG and minimal (<20% of the time) slow-wave activity.

Question 6

Stage 3 EEG

Answer 6

High amplitude slow waves

Contains delta EEG activity with a 75 µV or greater amplitude enduring for 20% or more of the duration

Question 7

REM EEG

Answer 7

Similar to wakefulness EEG, sensory disconnected from environment

Saccadic eye movements occur during epochs with low-voltage, mixed-frequency EEG in association with a very low level of EMG activity.

Question 8

Proportions spent in each sleep phase?

Answer 8

REM sleep accounts for approximately 20% to 25% of total sleep time, stage N2 accounts for 50%, N3 accounts for 12.5% to 20%, and N1 accounts for the remainder.

Question 9

Sleep oscillations

Answer 9

Rhythmic and/or repetitive electrical activity generated spontaneously and in response to stimuli by neural tissue in the central nervous system

Question 10

Slow waves divided into

Answer 10

Slow oscillation (0.2-1 Hz)
Delta (1-4 Hz)
Spindle (7-15 Hz
Theta (4-10 Hz)

Question 11

Three areas controlling sleep oscillations

Answer 11

Cortex, thalamus, reticular nucleus of thalamus

Question 12

Thalamus sends what signals to RTN and cortex

Answer 12

Glutaminergic

Question 13

Cortex sends what signals to RTN and thalamus

Answer 13

Glutaminergic

Question 14

Reticular neurons sends what signals to where

Answer 14

GABAergic inhibitory output to the thalamocortical neurons

Question 15

What is a sleep spindle

Answer 15

0.5-second (or longer) burst of 12- to 14-Hz activity

Question 16

What initiates spindles

Answer 16

Thalamic reticular nucleus and regulated by thalamo-reticular and thalamo-cortical circuits.

Question 17

What disorder leads to deficits in spindle activity?

Answer 17

Schizophrenia

Question 18

What diffuse subcortical neuromodulatory systems regulate global brain states

Answer 18

Cholinergic 
Adrenergic 
Histaminergic 
Dopamine 
Serotonin 
Orexin/Hypocretin

Question 19

Where are orexin neurons

Answer 19

Lateral nucleus of the hypothalamus

Question 20

Cholinergic nuclei are located?

Answer 20

Lateral dorsal tegmentum and posterior pontine tegmentum

Basal forebrain

Question 21

Cholinergic neuron effect on arousal

Answer 21

Maintain awake state

Question 22

Monoaminergic nuclei that project to forebrain include

Answer 22

Noradrenergic locus coeruleus, histaminergic neurons in the TMN, serotoninergic neurons in the median raphe nuclei, dopaminergic neurons in the vPAG and VTA

Question 23

Monoaminergic in wakefulness

Answer 23

Fire during wakefulness

Question 24

Monoaminergic neuron in sleep and REM sleep

Answer 24

Decrease activity during non-REM sleep, and silent during REM sleep

Question 25

Noradrenergic neurons in

Answer 25

Locus coeruleus

Question 26

Histaminergic neurons in

Answer 26

TMN

Question 27

Serotoninergic neurons in

Answer 27

Median raphe nuclei

Question 28

Dopaminergic neurons in the

Answer 28

VTA and vPAG

Question 29

Phenelzine can

Answer 29

Eliminate REM sleep

Question 30

When do Orexin neurons fire

Answer 30

Fire predominantly during wakefulness, and particularly during motivated behaviours

Question 31

Orexin neurons inhibited by

Answer 31

Glucose, (activated when glucose is low)

Question 32

Orexin destruction leads to

Answer 32

Narcolepsy

Question 33

What is the sleep promoting area

Answer 33

VLPO (ventral lateral preoptic nucleus)

Question 34

What is the wake promoting area

Answer 34

TMN (histamine), LC (noradrenaline), LH (orexin), VTA (dopamine)

Question 35

How do wake promoting and sleep promoting areas communicate?

Answer 35

Inhibitory connections

Question 36

Sleep promoting neurons are

Answer 36

GABAergic neurons in preoptic hypothalamus

Question 37

Why do benzodiazepines make you sleepy?

Answer 37

Potentiate GABA (preoptic sleep promoting area)

Question 38

How is REM sleep controlled?

Answer 38

REM-on cells and REM-off cells

Question 39

What is a circadian rhythm?

Answer 39

Natural, internal process that regulates the sleep–wake cycle and repeats on each rotation of the Earth roughly every 24 hours. Any biological process that displays an endogenous, entrainable oscillation of about 24 hours.

Question 40

Master circadian clock is?

Answer 40

SCN

Question 41

SCN input

Answer 41

Light information by a direct retinohypothalamic tract (RHT) to entrain the clock to the 24-h day.

Question 42

What is a zeitgeber?

Answer 42

Cue in the regulation of the body's circadian rhythms.

Question 43

What regulates the timing of melatonin synthesis?

Answer 43

The SCN clock

Question 44

Where is melatonin released from?

Answer 44

Pineal

Question 45

When is melatonin secreted?

Answer 45

At night

Question 46

What does it mean to be able to synchronise and reset biological oscillations?

Answer 46

Chronobiotic effects

Question 47

Responsiveness of SCN neurons to melatonin is greatest

Answer 47

Around subjective dusk

Question 48

Role of melatonin

Answer 48

Chronobiotic, feedback to SCN clock

Question 49

Sleep after sleep deprivation is

Answer 49

Deeper, not necessarily longer

Question 50

Elderly sleep

Answer 50

Advanced sleep timing (i.e. earlier bedtimes and rise times) Longer sleep-onset latency (i.e longer time taken to fall asleep) Shorter overall sleep duration Increased sleep fragmentation (i.e. less consolidated sleep with more awakenings, arousals, or transitions to lighter sleep stages) More fragile sleep (i.e. higher likelihood of being woken by external sensory stimuli) Reduced amount of deeper NREM sleep known as slow wave sleep (SWS), increased time spent in lighter NREM stages 1 and 2, shorter and fewer NREM-REM sleep cycles, increased time spent awake throughout the night.

Question 51

Consequences of sleep deprivation

Answer 51

Decreased alertness Increased attentional lapses Decreased hand-eye coordination Decreased attention and sustained vigilance Decreased olfactory discrimination Impaired verbal learning, deficit in temporal memory, impairment in working memory Reduced verbal fluency Reduced capacity to modify behaviour rapidly and flexibly to changing demands Reduced inhibitory control Impaired capacity to integrate emotional cues into the decision-making process, impaired judgement.