Which type of brain waves are typically associated with stage 2 sleep?

Stage 2 sleep is characterized by specific brain activity that plays a crucial role in the sleep cycle. During this stage, sleep spindles are the hallmark feature. Sleep spindles are bursts of oscillatory brain activity that occur most commonly in non-REM sleep. They are thought to be involved in memory consolidation and the processing of information.

In addition to sleep spindles, stage 2 sleep also sees the presence of K-complexes, which are large, high-voltage brain waves that may represent a response to external stimuli. However, it is the sleep spindles that are most specifically associated with this stage and are important for maintaining sleep.

In contrast, alpha waves are typically observed during wakefulness and relaxation; delta waves are associated with deep sleep (stage 3 and 4); and theta waves occur during light sleep and the transition between wakefulness and sleep. Therefore, the presence of sleep spindles is what distinguishes stage 2 sleep from other stages.