L9 - Intro to Sleep

Question 1

What is sleep?

Answer 1

A condition of body and mind, which typically recurs for several hours per day, in which the eyes are closed, the postural muscles relax and consciousness is practically suspended.

Question 2

what are ways we can measure sleep?

Answer 2

EEG - summated brain wave activity
EOG - eye movement
EMG - muscle tone

Question 3

What kind of EEG do we see in wakefulness?

Answer 3

• alpha - rested

- Beta - awake

Question 4

What kind of EEG do we see in nREM 1?

Answer 4

• back and forth from stage 1 to relaxed wakefulness
• theta waves - less waves, slower freq
• K - COMPLEXES … after a few of these = person entered stage 2

Question 5

What kind of EEG do we see in STAGE 2 NREM?

Answer 5

• bigger K complexes - half to 1s duration
• sleep spindles - 14hz, half to 3 secs
• mainly theta waves

slow rolling eye movements have ceased.

Question 6

What kind of EEG do we see in STAGE 3 NREM?

Answer 6

• K complexes start to occur in runs, turns into DELTA WAVES
• delta = half to 2hz

30% of epoch is delta, rest is theta

Question 7

What kind of EEG do we see in STAGE 4 NREM

Answer 7

more than 50% of epoch is DELTA WAVES, rest is theta

• synonymous firing

Question 8

What kind of EEG do we see in REM

Answer 8

• paralysed, no movements
• rapid eye movements
• saw tooth waves, doesn’t have to be there but often is
• low amplitude fast waves - THETA like in stage 1

Question 9

what stages are deemed to be SWS

Answer 9

STAGE 3 AND 4

Question 10

what are some characteristics, other than EEG of non rem sleep?

Answer 10

• light even respiration and reg heart rate
• muscle control is present - tossing and turning
• cog activity. hard to wake up from SWS

Question 11

What are some characteristics of REM sleep

Answer 11

• theta activity, desynchronised pattern
• enhanced and variable respiration and blood pressure
• rapid eye movements
• vivid dreams
• signs of sexual arousal
• loss of muscle tone

Question 12

What is the stereotypical pattern of sleep over one night?

Answer 12

• 90 min cycles
• SWS decreases over night
• REM increases over the night

Question 13

What is the trend of sleep over age?

Answer 13

• sleep decreases with age
• REM = easy to wake up from
• lots of REM in babies, around 50% of sleep

Question 14

What is the borbley 2 factor model?

Answer 14

2 factors that control how much we sleep, and when we sleep.

• homeostatic factor (process s)
• circadian factor (process c)

Question 15

Describe the homeostatic control of sleep.

Answer 15

• regulatory processes ensure that appropirate levels of sleep occur, including rebound effects.
• if sleep is reduced, negative consequences ensue.

homeostatic process is reflected in SWS!!!!!

sws increases after not sleeping

HYPOTHESISED TO INCREASE EXPONENTIALLY DURING WAKEFULNESS AND DECREASE DURING SLEEP

Question 16

Describe the circadian control of sleep.

Answer 16

• one cycle is about 24 hours
• internally driven, dont NEED external factors
• light is an external cue that can set the circadian rhythm, but even w/o light, some rhythm can be see.

When participants were told they can turn lights on and off as they please, they went to sleep progressively later and later and started living on a 25 hour day… suggests that internal rhythm is more than 24 hours.