Circadian rhythm
the physical, mental, and behavioral changes an organism experiences over a 24-hour cycle
Dreams
a series of thoughts, images, and sensations occurring in a person's mind during sleep.
Electroencephalograph (EEG)
the electrical activity of the brain
Hypersomnia
a condition in which you feel extreme daytime sleepiness despite getting sleep that should be adequate (or more than adequate).
Insomnia
you may have trouble falling asleep, staying asleep, or getting good quality sleep
Melatonin
a hormone that your brain produces in response to darkness
Napping
a short period of sleep that usually occurs during the day
Narcolepsy
a chronic neurological disorder that affects the brain's ability to control sleep-wake cycles
Night Terrors
a sleep disorder in which a person quickly awakens from sleep in a terrified state.
Nightmares
a disturbing dream associated with negative feelings, such as anxiety or fear that awakens you
Parasomnia
occur in a state that lies between sleep and wakefulness
Restless Legs Syndrome
A condition characterized by a nearly irresistible urge to move the legs, typically in the evenings.
Sleep
Sleep is important to a number of brain functions, including how nerve cells (neurons) communicate with each other
Sleep apnea
a potentially serious sleep disorder in which breathing repeatedly stops and starts
Sleep deprivation
occurs when an individual fails to get the amount of sleep that they need
Sleep paralysis
a feeling of being conscious but unable to move
Sleep study
a test used to diagnose sleep disorders.
Snoring
the hoarse or harsh sound that occurs when air flows past relaxed tissues in your throat, causing the tissues to vibrate as you breathe
Stage 1 (Non-REM) sleep
heartbeat, eye movements, brain waves, and breathing activity begin to taper down
Stage 2 (Non-REM) sleep
Stage 2 is still light sleep, but deeper than stage 1
Stage 3 (Non-REM) sleep
N3 or deep sleep
Stage 4 (REM Sleep)
your voluntary muscles become immobilized
Somnambulism
sleepwalking.
Wakefulness
a daily recurring brain state and state of consciousness in which an individual is conscious and engages in coherent cognitive and behavioral responses to the external world