Chapter 14: Sleep, Dreaming, and Circadian Rhythms

5-hydroxytryptophan

precursor to serotonin

activation-synthesis hypothesis

The theory that the information supplied to the cortex by the brain stem during REM sleep is largely random and that the resulting dream is the cortex's best effort to make sense of those random signals.

adaptation theories of sleep

Theories of sleep based on the premise that sleep evolved to protect organisms from predation and accidents and to conserve their energy, rather than to fulfill some particular physiological need

antihypnotic drugs

Sleep reducing drugs

Benzodiazepines

drugs that lower anxiety and reduce stress

carousel apparatus

An apparatus used to study the effects of sleep deprivation in laboratory rats

cataplexy

A disorder that is characterized by recurring losses of muscle tone during wakefulness and is often seen in cases of narcolepsy

cerveau isole preparation

An experimental preparation in which the forebrain is disconnected from the rest of the brain by a midcollicular transection

chronobiotic

A substance that influences the timing of internal biological rhythms

circadian clock

an internal mechanism that maintains a 24-hour activity rhythm or cycle

circadian rhythms

biological patterns that occur at regular intervals as a function of time of day

delta waves

the large, slow brain waves associated with deep sleep

desynchronized EEG

Also called beta activity. A pattern of EEG activity comprising a mix of many different high frequencies with low amplitude.

electromyogram

record of the electrical activity in a muscle

electrooculogram

measures eye movements

emergent stage 1 EEG

All periods of stage 1 sleep EEG except initial stage 1; each is associated with REMs

encephale isole preparation

An experimental preparation in which the brain is separated from the rest of the nervous system by a transection of the caudal brain stem

executive function

conscious control of thoughts, emotions, and actions to accomplish goals or solve problems

free-running period

The duration of one cycle of a free-running rhythm

free-running rhythms

Circadian rhythms that do not depend on environmental cues to keep them on a regular schedule

hypersomnia

Disorders characterized by excessive sleep or sleepiness

hypnagogic hallucinations

dreamlike experiences during wakefulness

hypnotic drugs

Sleep-promoting drugs

iatrogenic

produced by a physician

Imidazopyridines

A class of GABA(a) agonists that were marketed for the treatment of insomnia.

initial stage 1 EEG

The period of the stage 1 EEG that occurs at the onset of sleep; it is not associated with REM

insomnia

recurring problems in falling or staying asleep

internal desynchronization

The cycling on different schedules of the free-running circadian rhythms of two different processes

jet lag

The adverse effects on body function of the acceleration of zeitgebers during east-bound flights or their deceleration during west-bound flights

melanopsin

a photopigment, found in a class of photoreceptive retinal ganglion cells

melatonin

A hormone manufactured by the pineal gland that produces sleepiness.

microsleeps

brief episodes of sleep lasting only a few seconds

monophasic sleep cycles

Sleep cycles that regularly involve only one period of sleep per day, typically at night

narcolepsy

A sleep disorder characterized by uncontrollable sleep attacks. The sufferer may lapse directly into REM sleep, often at inopportune times.

orexin

a neuropeptide that has been implicated in narcolepsy; sometimes called hypocretin

periodic limb movement disorder

a sleep disorder characterized by repeated involuntary movement of the legs and sometimes the arms

pineal gland

endocrine gland located near the base of the cerebrum; secretes melatonin

polyphasic sleep cycles

Sleep cycles that regularly involve more than one period of sleep per day

recuperation theories of sleep

Theories based on the premise that being awake disturbs the body's homeostasis and the function of sleep is to restore it

REM sleep

Rapid eye movement sleep, a recurring sleep stage during which vivid dreams commonly occur. Also known as paradoxical sleep, because the muscles are relaxed (except for minor twitches) but other body systems are active.

REM-sleep behavior disorder

a neurological disorder in which the person does not become paralyzed during REM sleep and thus acts out dreams

restless legs syndrome

a neurological disorder characterized by uncomfortable feelings in the legs, producing a strong urge to move them

reticular activating system

the part of the brain that is involved in attention, sleep, and arousal

sleep apnea

a sleep disorder characterized by temporary cessations of breathing during sleep and repeated momentary awakenings

sleep inertia

a state characterized by cognitive impairment, grogginess, and disorientation that is experienced upon rising from short sleep or an overly long nap

sleep paralysis

the experience of waking up unable to move

slow-wave sleep

non-REM sleep, characterized by synchronized EEG activity during its deeper stages

suprachiasmatic nuclei

nuclei in the hypothalamus that generate biological rhythms

tau

The first circadian gene to be identified in mammals

zeitgebers

Environmental cues, such as the light-dark cycle, that entrain circadian rhythms