The presence of sleep spindles and V-waves in the EEG indicates which stage of sleep?

The presence of sleep spindles and V-waves in the EEG is characteristic of Stage 2 sleep. Sleep spindles are bursts of oscillatory brain activity that occur during non-rapid eye movement (NREM) sleep and are particularly prominent during Stage 2. They represent a period of sleep when the brain is processing information and have been linked to memory consolidation.

V-waves, also known as vertex waves, are additional features found in Stage 2 sleep and contribute to the distinctive EEG pattern observed during this stage. In contrast, the other stages of sleep exhibit different EEG patterns: Stage 1 shows a mix of theta waves, Stage 3/4 is marked by delta waves, and REM sleep is characterized by a low-voltage mixed frequency activity similar to wakefulness, often lacking prominent sleep spindles. Thus, the correlation of sleep spindles and V-waves specifically indicates that the individual is in Stage 2 sleep.