Chapter 14 Flashcards & Key Terms

alpha rhythm
A brain potential of 8 to 12 Hz that occurs during relaxed wakefulness.
basal forebrain
A ventral region in the forebrain that has been implicated in sleep.
cataplexy
Sudden loss of muscle tone, leading to collapse of the body without loss of consciousness.
circadian rhythm
A pattern of behavioral, biochemical, or physiological fluctuation that has a 24-hour period.
circannual
Occurring on a roughly annual basis.
delta wave
The slowest type of EEG wave, characteristic of stages 3 and 4 slow-wave sleep.
desynchronized EEG
Also called beta activity. A pattern of EEG activity comprising a mix of many different high frequencies with low amplitude.
dimer
A complex of two proteins that have bound together.
diurnal
Active during the light periods of the daily cycle.
ecological niche
The unique assortment of environmental opportunities and challenges to which each organism is adapted.
electroencephalography (EEG)
The recording and study of gross electrical activity of the brain recorded from large electrodes placed on the scalp.
electromyography (EMG)
The electrical recording of muscle activity.
electro-oculography (EOG)
The electrical recording of eye movements.
entrainment
The process of synchronizing a biological rhythm to an environmental stimulus.
fatal familial insomnia
An inherited disorder in which humans sleep normally at the beginning of their life but in midlife stop sleeping, and 7–24 months later die.
free-running
Referring to a rhythm of behavior shown by an animal deprived of external cues about time of day.
general anesthetic
A drug that renders an individual unconscious.
hypocretins
Also called orexins. Neuropeptides produced in the hypothalamus that are involved in switching between sleep states, in narcolepsy, and in the control of appetite.
infradian
Referring to a rhythmic biological event whose period is longer than that of a circadian rhythm—that is, longer than a day.
isolated brain
Sometimes referred to by the French term, encéphale isolé. An experimental preparation in which an animal’s brainstem has been separated from the spinal cord by a cut below the medulla.
isolated forebrain
Sometimes referred to by the French term, cerveau isolé. An experimental preparation in which an animal’s nervous system has been cut in the upper midbrain, dividing the forebrain from the brainstem.
K complex
A sharp negative EEG potential that is seen in stage 2 sleep.
melanopsin
A photopigment found within particular retinal ganglion cells that project to the suprachiasmatic nucleus.
narcolepsy
A disorder that involves frequent, intense episodes of sleep, which last from 5 to 30 minutes and can occur anytime during the usual waking hours.
night terror
A sudden arousal from stage 3 or stage 4 slow-wave sleep that is marked by intense fear and autonomic activation.
nightmare
A long, frightening dream that awakens the sleeper from REM sleep.
nocturnal
Active during the dark periods of the daily cycle.
period
The interval of time between two similar points of successive cycles, such as sunset to sunset.
phase shift
A shift in the activity of a biological rhythm, typically provided by a synchronizing environmental stimulus.
pineal gland
A secretory gland in the brain midline; the source of melatonin release.
rapid-eye-movement (REM) sleep
Also called paradoxical sleep. A stage of sleep characterized by small-amplitude, fast-EEG waves, no postural tension, and rapid eye movements. REM rhymes with “gem.”
REM behavior disorder (RBD)
A sleep disorder in which a person physically acts out a dream.
reticular formation
An extensive region of the brainstem (extending from the medulla through the thalamus) that is involved in arousal (waking).
retinohypothalamic pathway
The projection of retinal ganglion cells to the suprachiasmatic nuclei.
sleep apnea
A sleep disorder in which respiration slows or stops periodically, waking the patient. Excessive daytime somnolence results from the frequent nocturnal awakening.
sleep cycle
A period of slow-wave sleep followed by a period of REM sleep. In humans, a sleep cycle lasts 90–110 minutes.
sleep deprivation
The partial or total prevention of sleep.
sleep enuresis
Bed-wetting.
sleep paralysis
A state during the transition to or from sleep, in which the ability to move or talk is temporarily lost.
sleep recovery
The process of sleeping more than normally after a period of sleep deprivation, as though in compensation.
sleep spindle
A characteristic 14- to 18-Hz wave in the EEG of a person said to be in stage 2 sleep.
sleep state misperception
Commonly, a person’s perception that he has not been asleep when in fact he was. Typically occurs at the start of a sleep episode.
sleep-maintenance insomnia
Difficulty in staying asleep.
sleep-onset insomnia
Difficulty in falling asleep.
slow-wave sleep (SWS)
Sleep, divided into stages 1–4, that is defined by the presence of slow-wave EEG activity.
somnambulism
Sleepwalking.
stage 1 sleep
The initial stage of slow-wave sleep, which is characterized by small-amplitude EEG waves of irregular frequency, slow heart rate, and reduced muscle tension.
stage 2 sleep
A stage of slow-wave sleep that is defined by bursts of regular 14- to 18-Hz EEG waves called sleep spindles.
stage 3 sleep
A stage of slow-wave sleep that is defined by the spindles seen in stage 2 sleep, mixed with larger-amplitude slow waves.
stage 4 sleep
A stage of slow-wave sleep that is defined by the presence of delta waves at least half the time.
sudden infant death syndrome (SIDS)
Also called crib death. The sudden, unexpected death of an apparently healthy human infant who simply stops breathing, usually during sleep.
suprachiasmatic nucleus (SCN)
A small region of the hypothalamus above the optic chiasm that is the location of a circadian oscillator.
tuberomammillary nucleus
A region of the basal hypothalamus, near the pituitary stalk, that plays a role in generating SWS.
ultradian
Referring to a rhythmic biological event whose period is shorter than that of a circadian rhythm, usually from several minutes to several hours long.
vertex spike
A sharp-wave EEG pattern that is seen during stage 1 slow-wave sleep.
zeitgeber
Literally “time-giver” (in German). The stimulus (usually the light-dark cycle) that entrains circadian rhythms.
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