Lecture — why we sleep

Lecture summary: The speaker argues that sleep is not passive rest but active maintenance. During deep sleep the brain clears metabolic waste; during REM sleep it consolidates memory. Cutting sleep by two hours a night for a week produced measurable drops in attention in the study cited, and participants consistently underestimated how impaired they were. Re-tell the lecture in your own words. You have 10 seconds to prepare and 40 seconds to speak.