This image depicts the sleep cycles over the course of a typical night. In which stage are K-complexes and sleep spindles most likely to occur?
A)stage 1 NREM
B)stage 2 NREM
C)REM sleep
D)stage 4 NREM

Question

This image depicts the sleep cycles over the course of a typical night. In which stage are K-complexes and sleep spindles most likely to occur? 
A)stage 1 NREM 
B)stage 2 NREM 
C)REM sleep 
D)stage 4 NREM

Quizplus · Accepted Answer

K-complexes and sleep spindles occur most frequently in stage 2 NREM sleep. K-complexes are large, slow brain waves that occur in response to external stimuli, while sleep spindles are bursts of rapid brain activity. Both are characteristic of stage 2 NREM sleep.

This Image Depicts the Sleep Cycles Over the Course of a Typical