PSYCHOLOGY OF EMOTIONS

Detailed explanation-1: -This drowsy period, called stage I sleep, eventually gives way to light or stage II sleep, which is characterized by a further decrease in the frequency of the EEG waves and an increase in their amplitude, together with intermittent high-frequency spike clusters called sleep spindles.

Detailed explanation-2: -Sleep spindles, a defining characteristic of stage 2 sleep, are brief, powerful bursts of synchronous ∼12–15 Hz neuronal firing in thalamocortical networks that occur most frequently late in the night.

Detailed explanation-3: -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.

Detailed explanation-4: -Sleep spindles may be present in all stages of NREM, but they are most prevalent in stage 2 sleep. View Source, which we tend to enter for the first time shortly after falling asleep. Sleep spindles do not occur during REM sleep.