What is an electroencephalogram (EEG)?
It is the recording of gross electrical activity in the brain that can be used to classify levels of arousal and sleep
What are the two distinct classes of sleep?
Rapid-eye-movement sleep (REM) and Non-REM sleep
What is rapid eye movement sleep (REM)
It is characterized by small amplitude, fast-EEG waves; no postural tension; and rapid eye movements
Non-REM Sleep
Can be divided into three stages with distinct EEG waves
What does the pattern of activity in an awake, alert person contain?
Many EEG frequencies; mix of law amplitude waves with many fast frequencies (>15-20 Hz); aka beta activity/ de synchronized EEG
What does the relaxed mind exhibit?
An alpha rhythm
What is a alpha rhythm?
A regular oscillation at a frequency of 8–12 Hz
What is stage 1 of Non-EEM sleep?
- Time spent in alpha rhythm decreases
- Waves of smaller amplitude and irregular frequency begin
- Vertex spikes, or sharp waves, appear
- Heart rate slows, muscles relax, eyes roll about slowly
- Lasts several minutes
What is stage 2 of Non-EEM sleep?
- Sleep spindles—bursts of 12–14 Hz waves
- K-complexes
- sharp negative EEG potentials
What is stage 3 of Non-EEM sleep?
- Delta waves—large-amplitude, very slow waves
- About one per second
Characterize of REM Sleep
- Small-amplitude, high-frequency activity, like an awake person
- Eyes dart rapidly under closed lids
- Muscles relaxed
- Aka atonia
What is REM sleep aka?
paradoxical sleep
What is a typical night of sleep in young adults?
- Total sleep time ranges from 7–8 hours
- About half is stage 2 sleep
- About 20% is REM sleep
- Cycles last 90–110 minutes
- Cycles early in the night have more stage 3 SWS (slow wave sleep)
- Later cycles have more REM sleep
What is dream during REM sleep characterized as?
Visual imagery; sounds, smell, emotions
What are dream during Non-REM sleep characterized as?
Thinking type
What are nightmares?
Long, frightening dreams that awaken the sleeper from REM sleep
What are Night Terrors?
Sudden arousal from stage 3 SWS (slow wave sleep) marked by intense fear and autonomic activation; common in children during early parts of an evening nap
Nearly all animals display both REM and SWS
Dolphins do not show REM sleep
Both dolphins and birds only have one hemisphere meter SWS while the other remains awake
