Sleep Physiology Examination Paper MCQs

Question 1

Which thalamic nucleus is primarily responsible for relaying visual information to the cortex?

Accepted Answer

Medial geniculate body — The lateral geniculate body relays visual information from the retina to the visual cortex, while the medial geniculate body handles auditory information. ---

Question 2

The neurotransmitter primarily released by the locus coeruleus that promotes wakefulness is

Accepted Answer

Norepinephrine — The locus coeruleus is the primary source of norepinephrine in the brain and is a key component of the ascending arousal system. ---

Question 3

Sleep spindles are characteristic of which stage of NREM sleep?

Accepted Answer

Stage 2 — Sleep spindles (10-14 Hz bursts) are the defining feature of Stage 2 NREM sleep, generated by the thalamic reticular nucleus. ---

Question 4

The master circadian pacemaker is located in the

Accepted Answer

Suprachiasmatic nucleus — The SCN receives direct input from the retina via the retinohypothalamic tract and coordinates circadian rhythms. ---

Question 5

PGO spikes during REM sleep originate from

Accepted Answer

PGO spikes — PGO spikes are generated in the pons and travel through the lateral geniculate nucleus to the occipital cortex, marking REM sleep onset. ---

Question 6

The EEG frequency range for alpha rhythm is

Accepted Answer

8-13 Hz — Alpha rhythm (8-13 Hz) is seen in awake, resting adults with eyes closed. ---

Question 7

Which neurotransmitter is inhibitory and promotes sleep when released from the preoptic area?

Accepted Answer

GABA — GABA neurons in the preoptic area of the hypothalamus are sleep-promoting and inhibit arousal systems. ---

Question 8

The approximate duration of a complete sleep cycle is

Accepted Answer

90 minutes — Sleep cycles average 90 minutes, with 4-6 cycles occurring during a typical 8-hour sleep period. ---

Question 9

Delta waves are most prominent during

Accepted Answer

Stage 3 NREM — Delta waves (0.5-4 Hz) define Stage 3 NREM (slow-wave sleep). ---

Question 10

Melatonin is synthesized in the

Accepted Answer

Pineal gland — The pineal gland produces melatonin in response to darkness, regulated by the SCN. ---

Question 11

Which of the following is characteristic of REM sleep?

Accepted Answer

Muscle atonia — REM sleep is characterized by muscle atonia to prevent acting out dreams. ---

Question 12

The percentage of REM sleep in full-term neonates is approximately

Accepted Answer

25% — Full-term neonates spend about 50% of sleep time in REM, decreasing to 25% in adults. ---

Question 13

Beta rhythm is associated with

Accepted Answer

Alert wakefulness — Beta rhythm (13-30 Hz) appears during focused attention and mental tasks. ---

Question 14

Orexin neurons are located in the

Accepted Answer

Thalamus — Orexin (hypocretin) neurons in the lateral hypothalamus stabilize sleep-wake transitions. ---

Question 15

The EEG in REM sleep shows

Accepted Answer

Low-voltage, fast activity — REM sleep EEG resembles waking EEG, hence "paradoxical sleep." ---

Question 16

Chandelier cells in the cortex

Accepted Answer

Chandelier cells — Chandelier cells are inhibitory interneurons that synapse on axon initial segments. ---

Question 17

The bulboreticular facilitatory area is most active during

Accepted Answer

Morning awakening — This area becomes maximally active in the morning to overcome sleep-promoting influences. ---

Question 18

Which nucleus produces serotonin?

Accepted Answer

Raphe nuclei — The raphe nuclei in the brainstem are the primary source of serotonin. ---

Question 19

K-complexes are seen in

Accepted Answer

Stage 2 NREM — K-complexes are large, slow waves appearing in Stage 2 NREM sleep. ---

Question 20

The retinohypothalamic tract carries information about

Accepted Answer

Light-dark cycles — This tract carries non-visual light information to the SCN for circadian regulation. ---

Question 21

Histamine promotes wakefulness and is released from

Accepted Answer

Tuberomammillary nucleus — The tuberomammillary nucleus in the posterior hypothalamus releases histamine. ---

Question 22

Which sleep stage is most restorative?

Accepted Answer

Stage 3 NREM — Stage 3 NREM (slow-wave sleep) is the most restorative stage. ---

Question 23

The ascending arousal system is primarily

Accepted Answer

Polysynaptic — It involves multiple synaptic connections from the brainstem and hypothalamus to the cortex. ---

Question 24

Dreams are most vivid and memorable during

Accepted Answer

REM sleep — REM sleep is associated with vivid, memorable dreaming. ---

Question 25

Light exposure suppresses melatonin by affecting

Accepted Answer

Suprachiasmatic nucleus — Light activates the SCN, which inhibits melatonin synthesis via sympathetic pathways. ---

Question 26

The thalamic reticular nucleus releases

Accepted Answer

GABA — The thalamic reticular nucleus is GABAergic and generates sleep spindles. ---

Question 27

As the night progresses, there is typically

Accepted Answer

Increased REM sleep — REM episodes become longer toward morning, while deep NREM sleep decreases. ---

Question 28

The EEG reflects

Accepted Answer

Postsynaptic potentials — EEG records summated postsynaptic potentials from dendrites in superficial cortical layers. ---

Question 29

Acetylcholine's role in sleep is complex because it

Accepted Answer

Promotes different aspects of both sleep and wake — Acetylcholine promotes wakefulness and also triggers REM sleep. ---

Question 30

The VPL and VPM nuclei relay

Accepted Answer

Somatosensory information — VPL and VPM nuclei relay somatosensory information to the postcentral gyrus. ---

Question 31

Muscle atonia during REM sleep is caused by

Accepted Answer

Spinal motor neuron inhibition — REM sleep involves active inhibition of spinal motor neurons. ---

Question 32

The percentage of total sleep time occupied by NREM sleep is approximately

Accepted Answer

75-80% — NREM sleep occupies about 75-80% of total sleep time. ---

Question 33

Sleep spindles are generated by

Accepted Answer

Sleep spindles — Sleep spindles are generated by rhythmic inhibition of thalamocortical relay neurons. ---

Question 34

Which brain region is most active during REM sleep?

Accepted Answer

Brainstem — The brainstem, particularly the pons, is highly active during REM sleep. ---

Question 35

Slow-wave sleep is characterized by

Accepted Answer

Stage 3 NREM — Stage 3 NREM is defined by slow, high-amplitude delta waves. ---

Question 36

The pedunculopontine nucleus releases

Accepted Answer

Acetylcholine — The pedunculopontine nucleus releases acetylcholine as part of the arousal system. ---

Question 37

Alpha blocking occurs when

Accepted Answer

Attention is focused — Alpha rhythm is replaced by beta rhythm when attention is focused. ---

Question 38

Brain metabolism during REM sleep is

Accepted Answer

Increased by 20% — Brain metabolism increases during REM sleep, reflecting high neural activity. ---

Question 39

The arousal threshold is highest during

Accepted Answer

REM sleep — Despite paradoxical brain activity, the arousal threshold is highest during REM sleep. ---

Question 40

Children compared to adults have

Accepted Answer

More Stage 4 sleep — Children have significantly more Stage 4 (deep) sleep than adults.

Sleep Physiology Examination Paper MCQs

Questions, Answers & Explanations