AP PSYCHOLOGY

Detailed explanation-1: -The K-Complex is a waveform identified on electroencephalography (EEG), which primarily occurs during Stage 2 (N2) of NREM sleep, along with sleep spindles, which make up the two distinct features seen in this stage.

Detailed explanation-2: -Along with another wave pattern called K-complexes, sleep spindles are considered a hallmark of stage 2 NREM sleep.

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. How are sleep spindles generated?

Detailed explanation-4: -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-5: -You then begin to sleep if you enter non-REM Stage 1. This is when Alpha waves get replaced primarily with theta waves. As you continue to non-REM stage 2, you still have theta waves, but now you also have sleep spindles and k-complexes. In non-REM stage 3, this is dominated by delta waves.