The structure of sleep

Polysomnography reveals a structured progression of sleep stages, each with distinct brain and body activity. Stage 1 is transitional, with rolling eye movements. Stage 2, true sleep, features K-complexes and spindles. Stages 3 and 4 are deep sleep, marked by high amplitude delta waves. After deep sleep, REM sleep occurs, characterized by rapid eye movements and muscle relaxation. Understanding these stages is crucial for exploring sleep's relationship with brain functions, especially memory.

What is the primary characteristic of stage 1 sleep?

• Rapid eye movements

• K-complexes

• Rolling eye movements

• High amplitude delta waves

Which waveform is associated with stage 2 sleep?

• Delta waves

• Spindles

• Alpha waves

• Theta waves

During which stage of sleep do delta waves become prominent?

• Stage 3

• Stage 4

• Stage 2

• Stage 1

What physiological changes occur during deep sleep?

• Increased heart rate

• Muscle relaxation

• Rapid eye movements

• Increased body temperature

What is a key feature of REM sleep?

• High amplitude delta waves

• Profound muscle relaxation

• Slow eye movements

• K-complexes