AP PSYCHOLOGY

Detailed explanation-1: -Brain activity on an EEG shows relatively low-voltage, mixed-frequency activity characterized by the presence of sleep spindles and K-complexes (Figure 2-2). It is hypothesized that sleep spindles are important for memory consolidation.

Detailed explanation-2: -Stage N2 Sleep Sleep spindles typically appear between 4 and 6 weeks of age. These rudimentary spindles are noted to be maximal over the central (vertex) regions and are typically of relatively lower amplitude and slightly lower frequency, but tend to remain about 12–14 Hz.

Detailed explanation-3: -Spindles occur during both light NREM sleep and deep slow-wave sleep, but not during REM sleep. Sleep spindles preferentially coincide with the up-states of high-amplitude slow waves, yet can likewise be observed on their own, as is often the case during light NREM sleep.

Detailed explanation-4: -During Stage 2 Sleep, breathing, heart rate, muscle tone, and temperature continue to slow. Brief bursts of high-frequency brain wave activity are superimposed on an EEG of varying frequency. These bursts of high-frequency activity are called sleep spindles.

Detailed explanation-5: -Human sleep spindles recorded through EEG mark several characteristic moments as sleep evolves during a night. They appear at the onset of NREMS stage N2 (10, 186), when consciousness fades.