Answer:
K-complexes
Explanation:
Like sleep spindles, K-complexes are defining brainwaves of stage 2 sleep. They differ from sleep spindles in their form. Unlike the rapid burst of activity represented by sleep spindles, K complexes are large waves that react to external stimuli while sleeping.
K-complexes also develop later than sleep spindles. Sleep spindles develop at about 6 weeks of age, while K-complexes do not show up until about 5 months.
K-complexes form as a reaction to external stimuli in the bedroom or outside while a person is asleep. Sleep spindles follow K-complexes as the brain works to stay asleep.
Abnormal K-complex activity is linked with epilepsy, restless legs syndrome (RLS), and obstructive sleep apnea. For example, RLS sufferers experience a higher volume of K-complexes, which typically happen right before the leg movements. This increased K-complex activity may contribute to the less restful sleep associated with restless legs syndrome.
