AP PSYCHOLOGY

Detailed explanation-1: -The second stage of NREM sleep on EEG shows theta waves, which, along with K-complexes and sleep spindles, are the defining characteristics of this stage. Any abnormalities in these waveforms are therefore picked up on EEG.

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: -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.

Detailed explanation-4: -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-5: -Sleep spindles-bursts of 11–15 Hz (sigma frequency band) activity, typically between 0.5 and 2 s in duration-are characteristic transient features of the sleep electroencephalogram (EEG). Spindles are most prominent during N2 sleep and are in fact a defining feature of this stage.