1. defenition of sleep & sleep structure

Question 1

explain the increased sensory threshold in sleep:

Answer 1

a more effective (bigger) stimulus needed to induce a sensory reaction than during waking.
The reactivity has decreased.

Question 1

what are the citeria for sleep?

Answer 1

1. immobility & eye closure (behavioural)
2. increased sensory threshold
3. typical EEG brain waves
4. deceased muscle tone
5. sleep homeostasis (like hunger/thirst)

Question 2

what does EEG stand for

Answer 2

electroencephalography; measurement of brain electrical activity. can be measured outside of bony skull structure
golden standard for sleep measurements, but only possible for species with a developed CNS

Question 3

what are the different vigilant states?

Answer 3

1. wake = low amplitude, high-freq
2. NREM (non-rapid eye movements) -> N1, N2, N3 = high amplitude, low-freq -> slow waves: Delta waves + sleep spindles and K-complexes (in N2)
   contains: decreased heart rate, blood pressure, body temp, brain-blood circulation; relaxed muscles; increased para-sympathetic activity
3. REM (rapid-eye movements) = low amplitude, high freq
   contains: irregular breathing, heart rate, blood pressure; non-functional temp. regulation; paralyzed muscles with twitches; erections

Question 4

what are the components of a Polysomnography

Answer 4

1. EEG
2. EMG - muscle tone assesment
3. EOG - eye movement assesment
   + possible
4. ECG - heart rate and breathing
5. snoring recording
6. oxygen saturation

Question 5

what is a hypnogram

Answer 5

the choreography of sleep: consisting of sleep cycles (each 90 min)
- Delta (slow wave) power decreases during the night
- proportion of REM increases during the night

Question 6

sleep homeostasis indicates

Answer 6

that long periods of wakefulness are followed by long periods or deep sleep