Problem 7 1.4
Sleep
Ways to measure sleep
EEG- electrodes attached to the scalp, measures electrical activity
EOG- eyes
EMG- neck/chin
Stages of sleep
Period of relaxed wakefulness, just before falling asleep (pre stage) – alpha waves
Stage one- irregular, jagged, low voltage theta/alpha waves – brain activity slows
Stage two- theta waves, high in voltage but low in frequency. Characterised by sleep
spindles and K-complexes
- Sleep spindles- 12-14Hz waves during bursts that last half a second
- K complex- sharp waves associated with temporary inhibition of neuronal firing
Stage 3- 20-50% delta waves (1-2Hz), slow wave sleep, non-REM
Stage 4- 50+% delta waves, slow wave sleep, non-REM
- Stages 3 and 4 dominate in early night
Each stage lasts around 90 minutes
REM- rapid eye movement sleep- irregular low voltage fast waves- high frequency –
increased neuronal activity
- Postural muscles are relaxed
- Deep sleep
- Rem occupies more in the morning
- Depends on the time of day not the amount of sleep- if you go to bed late, REM
still increases in the morning
Sleeping for a shorter amount of time is effective as you will still have the same
amount of slow wave sleep (3/4) but shorter amounts of REM sleep
GABA- main inhibitory neurotransmitter responsible for sleep
Polyphasic sleep cycle- sleeping more than once a day (DaVinci method- 15 mins
every 4 hours)
Sleep
Ways to measure sleep
EEG- electrodes attached to the scalp, measures electrical activity
EOG- eyes
EMG- neck/chin
Stages of sleep
Period of relaxed wakefulness, just before falling asleep (pre stage) – alpha waves
Stage one- irregular, jagged, low voltage theta/alpha waves – brain activity slows
Stage two- theta waves, high in voltage but low in frequency. Characterised by sleep
spindles and K-complexes
- Sleep spindles- 12-14Hz waves during bursts that last half a second
- K complex- sharp waves associated with temporary inhibition of neuronal firing
Stage 3- 20-50% delta waves (1-2Hz), slow wave sleep, non-REM
Stage 4- 50+% delta waves, slow wave sleep, non-REM
- Stages 3 and 4 dominate in early night
Each stage lasts around 90 minutes
REM- rapid eye movement sleep- irregular low voltage fast waves- high frequency –
increased neuronal activity
- Postural muscles are relaxed
- Deep sleep
- Rem occupies more in the morning
- Depends on the time of day not the amount of sleep- if you go to bed late, REM
still increases in the morning
Sleeping for a shorter amount of time is effective as you will still have the same
amount of slow wave sleep (3/4) but shorter amounts of REM sleep
GABA- main inhibitory neurotransmitter responsible for sleep
Polyphasic sleep cycle- sleeping more than once a day (DaVinci method- 15 mins
every 4 hours)
