SLUMBER CYCLES

摘要

During sleep, complex changes occur in the brain. These can be observed with an electroencephalogram (EEC), which measures the brain's electrical activity and associated brainwaves. After lying awake for 10 minutes or so we enter non-rapid eye movement sleep or NREM sleep. NREM sleep is divided into three stages, NREM1, NREM2 and NREM3, based on subtle differences in EEC patterns. Each stage is considered progressively "deeper".