sleep spindles and k-complexes are most characteristic of the rem sleep stage.
sleep spindles and k-complexes are most characteristic of the rem sleep stage.
sleep spindles and k-complexes are most characteristic of which sleep stage ​?
rem sleep
the sleep cycle is normally defined in stages. when an individual first begins to sleep, stage 1 is entered, marked by the presence of some theta activity, which indicates that the firing of neurons in the neocortex is becoming more synchronized, as well as alpha wave activity (smooth electrical activity of 8–12 hz recorded from the brain, generally associated with a state of relaxation). this stage is a transition between sleep and wakefulness. an individual's eyelids will from time to time slowly open and close and their eyes will roll upward and downward. before one reaches sound sleep, stage 2 is entered. the eeg during this phase is normally irregular, but contains periods of theta activity, sleep spindles, and k complexes. sleep spindles are short bursts of waves of 12–14 hz that occur between two and five times a minute during states 1-4 of sleep. they appear to play a role in memory consolidation, and increased number of sleep spindles are correlated with increased scores on tests of intelligence. k complexes are sudden, sharp waveforms, which, unlike sleep spindles, are usually found only during stage 2 of sleep. they spontaneously occur at the rate of approximately one per minute, but often can be triggered by unexpected noises. it has been found that k complexes consist of isolated periods of inhibition. they appear to be the precursor of delta waves, also known as slow wave sleep, which appear during the deepest levels of sleep. both these stages are classified as non-rem sleep.
sleep onset
a study, using 49 rats indicated the increase of sleep spindles during slow-wave sleep following learning. it gave evidence to the increase of spindle frequency during non-rem sleep following paired associate of motor-skill learning tasks. using an eeg, sleep spindles were detected and showed to be present only during slow-wave sleep. beginning with a preliminary study, rats underwent six hours of monitored sleep, after a period of learning. results showed that during the first hour following learning, there was the most evident effect on learning-modulated sleep spindle density. however, this increase in spindle density was not dependent on the training condition. in other words, there was an increase in spindles regardless of how the rats were trained. eeg patterns showed a significant difference in the density of sleep spindles compared to the density of a control group of rats, who did not undergo any training before their sleep spindles were measured. this effect of increased spindle density only lasted for the first hour into sleep following training, and then disappeared within the second hour into sleep.
sleep and memory