EEG and sleep

Question 1

What is circadian rhythm?

Answer 1

• Cycle of which sleep and wakefullness follow

- Endogenous cycle of about 24hours and can persist without external cues

Question 2

What are zeitgebers?

Answer 2

• A rhythmically occurring natural, external phenomenon which acts as a cue in the regulation of the body’s circadian rhythms.
• Adapt the rhythm to the external environment

Question 3

What is the suprachiasmatic nucleus involved in?

Answer 3

Regulates the timing of sleep, not resposnsible for sleep itself

Question 4

What do lesions of the suprachiasmatic tract cause?

Answer 4

Dampening down of the circadian rhythm of sleep

Question 5

What is sleep defined as?

Answer 5

Reduced motor activity

Question 6

What does electro-myography measure?

Answer 6

Muscle movements

Question 7

What does electro-occulography measure?

Answer 7

Eye movements

Question 8

What does electro-encephalography measure?

Answer 8

Brain activity

• Measures the electrical activity from large populations of neurons in the brain
• Caused by cellular movements which create an electical field

Question 9

What are the positives of electroencephalography?

Answer 9

• Non-invasive
• Easy to administer
• Data easily gathered

Question 10

What happens to the body during non-REM sleep?

Answer 10

• Neuronal activity is low
• Metabolic rate and brain temperature at its lowest
• Heart rate and blood pressure decline (decreased sympathetic nervous system outflow)
• Increase in parasympathetic outflow dominates
• Muscle tone and reflexes intact

Question 11

How many stages of sleep are there?

Answer 11

5

• 4 non-REM sleep
• 1 REM sleep