1- How does the Brain Sleep? Flashcards
What is the ‘flip-flop’ mechanism?
When we are awake arousal systems inhibit the sleep promoting region, and when we are asleep the sleep promoting region inhibits the arousal systems
What are the two sleep promoting areas in the brain?
- Ventrolateral preoptic nucleus in the anterior hypothalamus (VLPO)
- Adjacent basal forebrain
What are the two wakefulness promoting areas in the brain?
- Posterior hypothalamus
- Adjacent midbrain
How is narcolepsy caused?
By an instability in the ‘flip-flop’ system
Which 5 neurotransmitters are involved in sleep?
- Acetylcholine
- Norepinephrine
- Serotonin
- Histamine
- Hypocretin
Which sleep neurotransmitter is particularly important?
Acetylcholine
Where is acetylcholine in the brain?
Neurons in pons and basal forebrain
What is adenosine’s role in sleep?
It builds up the longer you’ve been awake and levels drop when you fall asleep
Drowsiness is influenced more the longer you’ve been awake
Why does caffeine hide the feeling of tiredness?
Because it prevents us from detecting the adenosine
When does slow-wave sleep occur?
When neurons in the ventrolateral preoptic (VLPO) area become active
What is caused by the destruction of the preoptic area?
Total insomnia
What is caused by lesions to the reticular formation?
Reduced REM
What differs in different areas of the reticular formation?
They have different processes
When are we more common to dream?
In REM sleep
Where is cerebral blood flow high in REM?
In the visual association cortex
