Sleeping and Dreaming Pt. I Flashcards
circadian rhythm
A daily rhythmical change in behavior or physiological process.
zeitgebers
A stimulus (usually the light of dawn) that resets the biological clock that is responsible for circadian rhythms.
advanced sleep phase syndrome
A 4-hour advance in rhythms of sleep and temperature cycles, apparently caused by mutation of a gene (per2) involved in the rhythmicity of neurons of the SCN. People with this syndrome fall asleep around 7:30 pm and awaken around 4:30 am.
delayed sleep phase syndrome
A 4-hour delay in rhythms of sleep and temperature cycles, possibly caused by a mutation of gene (per3) involved in the rhythmicity of neurons in the SCN. People with this syndrome are typically unable to fall sleep before 2:00 pm and have great difficulty waking before midmorning.
pineal gland
A gland attached to the dorsal tectum; produces melatonin and plats a role in circadian and seasonal rhythms.
melatonin
A hormone secreted during the night by the pineal body; plays a role in circadian and seasonal rhythms.
suprachiasmatic nucleus (SCN)
A nucleus situated atop the optic chiasm. It contains a biological clock that is responsible for organizing many of the body’s circadian rhythms.
melanopsin
A photopigment present in ganglion cells in the retina whose axons transmit information to the SCN, the thalamus, and the olivary pretectal nucleus.
electromyogram (EMG)
An electrical potential recorded from an electrode placed on or in a muscle.
electro-oculogram (EOG)
An electrical potential from the eyes, recorded by means of electrodes placed on the skin around them; detects eye movements.
EEG Rhythms
alpha activity
Smooth electrical activity of 8-12 Hz recorded from the brain; generally associated with a state of relaxation.
beta activity
Irregular electrical activity of 13-30 Hz recorded from the brain; generally associated with a state of arousal.
theta activity
EEG activity of 3.5-7.5 Hz that occurs intermittently during early stages of slow-wave sleep and REM sleep.
delta activity
Regular synchronous electrical activity of less than 4 Hz recorded from the brain; occurs during the deepest stages of slow-wave sleep.
REM sleep
A period of desynchronized EEG activity during sleep, at which time dreaming, rapid eye movements, and muscular paralysis occur; also called paradoxical sleep.
non-REM sleep
All stages of sleep except REM sleep.
slow-wave sleep
Non-REM sleep, characterized by synchronized EEG activity during its deeper stages.
basic rest-activity cycle
A 90-minute cycle (in humans) of waxing and waning alertness, controlled by a biological clock in the caudal brain stem; controls cycles in REM sleep and slow-wave sleep.
