Brain activity decreases from wakefulness most notably in the cerebral cortex during which sleep stage?

Prepare for the Certification in Clinical Sleep Health exam. Use flashcards and multiple-choice questions with hints and explanations. Ace your exam!

Multiple Choice

Brain activity decreases from wakefulness most notably in the cerebral cortex during which sleep stage?

The main idea is how deeply the brain relaxes and how cortical activity changes across sleep stages. In deep non-REM sleep, the cortex undergoes the largest drop in activity from wakefulness. This stage is marked by slow-wave activity on EEG—large-amplitude delta waves—which reflects highly synchronized neuronal firing and a substantial reduction in metabolic demand. That combination means the cerebral cortex is far less active than when awake. In contrast, REM sleep features brain activity that can resemble wakefulness in many regions, even though the body is temporarily paralyzed. Stage 2 is lighter sleep, characterized by sleep spindles and K-complexes, with less reduction in cortical activity than deep non-REM sleep. So the stage with the most notable decrease in cortical brain activity from wakefulness is deep non-REM sleep.

The main idea is how deeply the brain relaxes and how cortical activity changes across sleep stages. In deep non-REM sleep, the cortex undergoes the largest drop in activity from wakefulness. This stage is marked by slow-wave activity on EEG—large-amplitude delta waves—which reflects highly synchronized neuronal firing and a substantial reduction in metabolic demand. That combination means the cerebral cortex is far less active than when awake.

In contrast, REM sleep features brain activity that can resemble wakefulness in many regions, even though the body is temporarily paralyzed. Stage 2 is lighter sleep, characterized by sleep spindles and K-complexes, with less reduction in cortical activity than deep non-REM sleep. So the stage with the most notable decrease in cortical brain activity from wakefulness is deep non-REM sleep.

More practice questions