AQA PSYA3 - Biological Rhythms - Sleep's Ultradian Rhythm

Sleep

Sleep Stages

Two main distinct forms of sleep: 

• REM (rapid eye movement)
• NREM (non-rapid eye movement).

EEG's measure electrical activity in the brain and show the stages of sleep.

• Clear wave form = synchronised 
• Unclear wave form = desynchronised
• Awake = fast desynchronised wave form.
• Synchronised wave forms are defined by frequency (Hz) and amplitude (size)

The stages of sleep on an EEG: (the first 4 stages are NREM)

• Awake: Beta wave; fast and desynchronised
• Relaxed: Alpha wave; slower, more regular, greater amplitude
• Stage 1: Light sleep shown by theta waves with small amplitude (4-7Hz). Also…