BRPT Sleep Physiology and Neuroanatomy 1 — Questions and Answers
Question 1: Which neurotransmitter, produced by the lateral hypothalamus, is the primary promoter of wakefulness and is deficient in narcolepsy type 1?
- GABA
- Orexin (hypocretin) (Correct answer)
- Serotonin
- Dopamine
Correct answer: Orexin (hypocretin)
Orexin (hypocretin) neurons in the lateral hypothalamus stabilize wakefulness, and their loss causes narcolepsy type 1 with cataplexy.
Question 2: The suprachiasmatic nucleus (SCN), which serves as the master circadian pacemaker, is located in which brain structure?
- Thalamus
- Brainstem
- Hypothalamus (Correct answer)
- Cerebellum
Correct answer: Hypothalamus
The SCN in the anterior hypothalamus receives light input via the retinohypothalamic tract and coordinates circadian timing throughout the body.
Question 3: Which hormone, secreted by the pineal gland in response to darkness, signals the circadian system to promote sleepiness?
- Cortisol
- Adenosine
- Melatonin (Correct answer)
- Histamine
Correct answer: Melatonin
Melatonin is released by the pineal gland during darkness and acts on SCN receptors to facilitate sleep onset and timing.
Question 4: What is the typical duration of one complete NREM-REM sleep cycle in healthy adults?
- 30–45 minutes
- 60–75 minutes
- 90–110 minutes (Correct answer)
- 120–140 minutes
Correct answer: 90–110 minutes
A complete sleep cycle averaging 90–110 minutes repeats 4–6 times per night, with REM periods lengthening in later cycles.
Question 5: Growth hormone secretion is predominantly linked to which sleep stage?
- REM sleep
- N1 sleep
- N2 sleep
- N3 (slow-wave) sleep (Correct answer)
Correct answer: N3 (slow-wave) sleep
Growth hormone is released in pulses tightly coupled to N3 slow-wave sleep, particularly in the first sleep cycle of the night.
Question 6: Which brain structure generates sleep spindles through thalamocortical circuits and acts as a relay station for sensory information during sleep-wake transitions?
- Hippocampus
- Amygdala
- Thalamus (Correct answer)
- Corpus callosum
Correct answer: Thalamus
The thalamus gates sensory input and, via thalamocortical networks, generates the 12–14 Hz sleep spindles that characterize N2 sleep.
BRPT Sleep Physiology and Neuroanatomy 1
Which neurotransmitter, produced by the lateral hypothalamus, is the primary promoter of wakefulness and is deficient in narcolepsy type 1?