Slow-wave sleep (SWS; non-REM sleep)

~   three/four stages
~   slow-wave EEG

Rapid-eye-movement sleep (REM)

~   small amplitude, fast-EEG waves,
~   no postural tension
~   rapid eye movements

Characteristics 

• Alpha Rhythms appear during relaxation
• Vertex spikes (sharp waves) appear during this stage
• Mainly theta brain waves but some alpha waves occur in this stage
• Short duration (10-15 min)
• Heart rate and muscle tension reduce, eyes (slow)

Characteristics

• Theta BW activity occurs
• Body temp drops
• Sleep spindles (short bursts of waves) occur in brief periods (12 to 14 Hz bursts). Then
• K-complexes (sharp negative waves) occur - only in this stage of sleep

Stage 3 sleep

• Transitional period between light and deep sleep.
• Sleep spindles
• More than 50% of BW activity is from theta waves
• Large, slow Delta waves emerge - key characteristic of this stage (less than 3.5 Hz)  

Stage 4 (late stage 3) sleep

• % Delta waves increase and predominate this stage but theta waves are involved.
• Very deep sleep
• Aka delta sleep

• Follows SWS 

Characteristics

• Active EEG (beta waves)
• Breathing and heart rate irregular
• Lack of muscle tone (paralyzation)
• Aka Paradoxical sleep
• Dreaming
• Rapid eye movements

Nondeclarative Memory (Implicit Memory): 

Ex: How to ride a bicycle

Associated with REM sleep

Declarative Memory (Explicit Memory):

Ex: Memory of an event; memorizing a list

Associated with SWS