AP PSYCHOLOGY

Detailed explanation-1: -Sleep spindles are bursts of neural oscillatory activity that are generated by interplay of the thalamic reticular nucleus (TRN) and other thalamic nuclei during stage 2 NREM sleep in a frequency range of  11 to 16 Hz (usually 12–14 Hz) with a duration of 0.5 seconds or greater (usually 0.5–1.5 seconds).

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: -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-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.

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.