waves and sleep stages

peak

top left arrow

wavelength

horizontal arrow

trough

bottom right arrow

amplitude

amplitude again

bottom right arrow

number of cycles per second

frequency

An amplified recording of the waves of electrical activity that sweep across the brain's surface.

EEG (electroencephalogram)

Beta Waves

• Desynchronization

• Awake but busy, active mind

Alpha Waves

• synchronized

• awake but relaxed

• proceeding stage 1

Theta Waves

• Stage 1 sleep

• 10-15mins

• 3.5-7.5Hz

sleep spindle

• Stage 2 sleep

• theta waves

• 14hz/sec waves 

• increase in FREQUENCY

k-complex

• Stage 2 sleep

• 14hz/sec waves 

• increase in AMPLITUDE

Delta Waves (2 stages)

• Stage 3 sleep

  • Less than 3.5hz

  • 20%-50% of sleep

  • Once occurring more than 50% → stage 4

• Stage 4 sleep

  • After 30-40 mins sleep

Order of REM sleep

1 2 3 4 3 2 REM 2 3 4 3 2 REM….

• Only go through stage 1 again if you wake up 

• Don’t need to know what happens after REM 

NREM alpha waves and theta waves; low frequency, high amplitude; deep relaxation state

stage 1

theta waves, sleep spindles, k-complexes

stage 2

periodically high increase in waves; maybe involved in memory and learning

sleep spindles

high spike up; when you wake up suddenly; maybe brain last ditch moment to check if anything is wrong; maybe environmental effects this

k-complexes

delta waves; deep sleep (slow-wave sleep); if woken, feel groggy and heightened sensitivity to pain

stage 3 & 4

similar brain waves to being awake; dreaming happens here; increase blood pressure and heart rate; sexual arousal

rapid eye movement (REM)

nonrapid eye movement sleep; encompasses all sleep stages except for REM sleep

NREM sleep