Electroencephalography (EEG)
How do they work?
What is amplitide? Frequency?
- Height of a wave
- cycles/second; how many oscillations per second (rate)
What stages include dreams?
All stages can involve dreams; stage 3 is least likely, REM has the most elaborate dreams
What happens with EEG during NREM and REM?
NREM: increase in amplitude and decrease in frequency (1-4)
REM: Low amplitude and high frequency
What is atonia?
Muscle relaxation-deeper than stage 4
What does it measure?
Brain activity in real time. Specifically measures voltage changes across time
What is synchrony?
How well each of the waveforms overlap each other
How long is each cycle? REM stages _______ and Stage 1 _______
~90 minutes. Grows longer; only happens once
Overall, what is the activity states of each?
NREM: low activity states for body and mind
REM: High activity states for body and mind
Awake states happen ______ with deep-sleep (comalike) states
Simultaneously
What is a limitation of EEG?
It only takes cortical recordings
What happens to amplitude, frequency, and synchrony when going from alert stage to sleep stage?
- Amplitude increases
- Frequency decreases
- Synchrony increases
What is an example of a sleep cycle?
S1-S2-S3-S4-S3-S2-REM
REM-S2-S3-S4-S3-S2-REM
REM-S2-S3-S2-REM
REM-S2-REM
REM-S2- Wake
What happens to the overall neural activity in both?
NREM: Decreases REM: High
What muscles are shut down during comalike REM?
All muscles except for face and ears
Why does it work?
The brain produces electricity from one cell to another (voltage)
What are the 5 wave types? What's the frequency of each?
Beta: 5-30hz
Alpha: 9-14hz
Theta: 4-8hz
Delta: 1-3 hz
Sleep spindles: 13-15hz
What are characteristics of each stage?
Stage 1: not "real sleep;" transition stage
Stage 2: Neither light nor deep
Stage 3: Deep sleep begins. Sleepwalking/talking
Stage 4: sleepwalking/talking. Deepest sleep
REM: emotionally charged, elaborate dreams
What happens to the parasympathetic and sympathetic response during each?
NREM: Parasympathetic increases, sympathetic decreases
REM: Parasympathetic is inhibited, sympathetic is activated
What are the characteristics of deep-sleep-like/coma-like REM sleep? (4)
Atonia, deregulated body temp, inhibition of reflexes, paralysis
What are the 3 reasons why EEG's are preferred?
1.) It's inexpensive
2.) Non-invasive
3.) Measure brain activity as neurons fire/activate- REAL TIME
What waves are associated with Stages 1, 2, 3, 4?
- 1: exclusively theta. Low amp, high freq, low synch
-2: theta and delta (more theta). Med amp, med freq, med synch
-3: delta and theta (more delta). High amp, low freq, high synch
-4: Exclusively delta. High amp, low freq, high synch
What are the percentages of each stage per sleep cycle?
Stage 1: 4-5%
Stage 2: 45-55%
Stage 3: 4-6%
Stage 4: 12-15%
REM: 20-25%
What happens to the metabolic rate and body temperature in both?
NREM: Metabolic rate decreases, body temp decreases
REM: Metabolic rate is high, body temp is deregulated
What are some miscellaneous awake-like states of REM sleep?
Rapid eye movements, easily awoken, most vivid and emotional dreams