14 - Biological Rhythms, Sleep, and Dreaming Flashcards
Diurnal
Active during the light periods of the daily cycle
Circadian rhythm
A pattern of behavioral, biochemical, or physiological fluctuation that has a 24-hour period
Nocturnal
Active during the dark periods of the daily cycle
Free-running
Referring to rhythm of behavior shown by an animal deprived of external cues about time of day
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
Entrainment
The process of synchronizing a biological rhythm to an environmental stimulus
Zeitgeber
Literally “time-giver.” The stimulus (usually the light-dark cycle) that entrains circadian rhythms.
Suprachiasmatic nucleus (SCN)
A small region of the hypothalamus above the optic chiasm that is the location of a circadian oscillator
Pineal gland
A secretory gland in the brain midline; the source of melatonin release
Retinohypothalamic pathway
The projection of retinal ganglion cells to the suprachiasmatic nuclei
Melanopsin
A photopigment found within particular retinal ganglion cells that project to the suprachiasmatic nucleus
Dimer
A complex of two proteins that have bound together
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.
Circannual
Occurring on a roughly annual basis
Infradian
Referring to a rhythmic biological event whose period is longer than that of a circadian rhythm-that is, longer than a day
Electroencephalography (EEG)
The recording and study of gross electrical activity of the brain recorded from large electrodes placed on the scalp
Electro-oculography (EOG)
The electrical recording of eye movements
Electromyography (EMG)
The electrical recording of muscle activity
Slow-wave sleep (SWS)
Sleep, divided into stages 1-4, that is defined by the presence of slow-wave EEG activity
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.
Desynchronized EEG
Also called beta activity. A pattern of EEG activity comprising a mix of many different high frequencies with low amplitude
Alpha rhythm
A brain potential of 8 to 12 Hz that occurs during relaxed wakefulness
Vertex spike
A sharp-wave EEG pattern that is seen during stage 1 sleep
Stage 1 sleep
The initial stage of 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 sleep that is defined by bursts of regular 14 to 18 Hz EEG waves called sleep spindles
Sleep spindle
A characteristic 14 to 18 Hz wave in the EEG of a person said to be in stage 2 sleep
K complex
A sharp negative EEG potential that is seen in stage 2 sleep
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
Delta wave
The slowest type of EEG wave, characteristic of stages 3 and 4 slow-wave sleep
Stage 4 sleep
A stage of slow-wave sleep that is defined by the presence of delta waves at least half of the time
Nightmare
A long, frightening dream that awakens the sleeper from REM sleep
Night terror
A sudden arousal from stage 3 or stage 4 slow-wave sleep that is marked by intense fear and autonomic activation
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 recovery
The process of sleeping more than normally after a period of sleep deprivation, as though in compensation
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
Ecological niche
The unique assortment of environmental opportunities and challenges to which each organism is adapted
General anesthetic
A drug that renders an individual unconscious
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
Basal forebrain
A ventral region in the forebrain that has been implicated in sleep
Tuberomammillary nucleus
A region of the basal hypothalamus, near the pituitary stalk, that plays a role in generating SWS
Reticular formation
An extensive region of the brainstem (extending from the medulla through the thalamus) that is involved in arousal (waking)
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
Cataplexy
Sudden loss of muscle tone, leading to collapse of the body without loss of consciousness
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
Sleep paralysis
A state during the transition to or from sleep in which the ability to move or talk is temporarily lost
Sleep enuresis
Bed-wetting
Somnambulism
Sleepwalking
REM behavior disorder (RBD)
A sleep disorder in which a person physically acts out a dream
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-onset insomnia
Difficultly in falling asleep
Sleep-maintenance insomnia
Difficultly in staying asleep
Sleep apnea
A sleep disorder in which respiration slows or stops periodically, waking the patient. Excessive daytime somnolence results from the frequent nocturnal awakening
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
