PSYCHOLOGY OF EMOTIONS

Detailed explanation-1: -The presence of sleep spindles is necessary and sufficient to define stage II sleep. Another characteristic finding of stage II sleep is the appearance of K complexes, but since K complexes are typically associated with a spindle, spindles are the defining features of stage II sleep.

Detailed explanation-2: -Sleep spindles may be present in all stages of NREM, but they are most prevalent in stage 2 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 2 Sleep 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-5: -Classical sleep spindles do not occur in prematures. They first appear clearly in the EEG during slow wave sleep from the 4th week postterm (44 weeks conceptional age) and are normally present in all infants’ EEGs by 9 weeks postterm.