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Introduction: When Sleep Gets Out of Control

PART I  Biological Rhythms

Many Animals Show Daily Rhythms in Activity

Circadian rhythms are generated by an endogenous clock

The Hypothalamus Houses a Circadian Clock

RESEARCHERS AT WORK: Transplants prove that the SCN produces a circadian rhythm

In mammals, light information from the eyes reaches the SCN directly

Circadian rhythms have been genetically dissected in flies and mice

PART II  Sleep

Human Sleep Exhibits Different Stages

We do our most vivid dreaming during REM sleep

Different species provide clues about the evolution of sleep

Our Sleep Patterns Change across the Life Span

Mammals sleep more during infancy than in adulthood

Most people sleep appreciably less as they age

Manipulating Sleep Reveals an Underlying Structure

Sleep deprivation impairs cognitive functioning but does not cause insanity

SIGNS & SYMPTOMS: Total Sleep Deprivation Can Be Fatal

Sleep recovery may take time

What Are the Biological Functions of Sleep?

Sleep conserves energy

Sleep enforces niche adaptation

Sleep restores the body and brain

Sleep may aid memory consolidation

Some humans sleep remarkably little, yet function normally

At Least Four Interacting Neural Systems Underlie Sleep

RESEARCHERS AT WORK: The forebrain generates slow wave sleep

The reticular formation wakes up the forebrain

The pons triggers REM sleep

PART III  Sleep Disorders

Sleep Disorders Can Be Serious, Even Life- Threatening

A hypothalamic sleep center was revealed by the study of narcolepsy

Some minor dysfunctions are associated with sleep

Some people appear to be acting out their nightmares

Insomniacs have trouble falling asleep or staying asleep

Although many drugs affect sleep, there is no perfect sleeping pill

Everyone should practice good sleep hygiene