- alpha wave
- type of brain wave characteristic during the early part of NREM stage 1 sleep, which has fairly low amplitude and a frequency of 8–12 Hz
- beta wave
- type of brain wave characteristic during wakefulness, which has a very low amplitude and a frequency of 13–30 Hz
- biological rhythm
- internal cycle of biological activity
- cataplexy
- lack of muscle tone or muscle weakness, and in some cases complete paralysis of the voluntary muscles
- central sleep apnea
- sleep disorder with periods of interrupted breathing due to a disruption in signals sent from the brain that regulate breathing
- circadian rhythm
- biological rhythm that occurs over approximately 24 hours
- codeine
- opiate with relatively low potency often prescribed for minor pain
- cognitive-behavioral therapy
- psychotherapy that focuses on cognitive processes and problem behaviors that is sometimes used to treat sleep disorders such as insomnia
- collective unconscious
- theoretical repository of information shared by all people across cultures, as described by Carl Jung
- consciousness
- awareness of internal and external stimuli
- continuous positive airway pressure (CPAP)
- device used to treat sleep apnea; includes a mask that fits over the sleeper’s nose and mouth, which is connected to a pump that pumps air into the person’s airways, forcing them to remain open
- delta wave
- type of brain wave characteristic during stage 3 NREM sleep, which has a high amplitude and low frequency of less than 3 Hz
- depressant
- drug that tends to suppress central nervous system activity
- euphoric high
- feelings of intense elation and pleasure from drug use
- evolutionary psychology
- discipline that studies how universal patterns of behavior and cognitive processes have evolved over time as a result of natural selection
- hallucinogen
- one of a class of drugs that results in profound alterations in sensory and perceptual experiences, often with vivid hallucinations
- homeostasis
- tendency to maintain a balance, or optimal level, within a biological system
- hypnosis
- state of extreme self-focus and attention in which minimal attention is given to external stimuli
- insomnia
- consistent difficulty in falling or staying asleep for at least three nights a week over a month’s time
- jet lag
- collection of symptoms brought on by travel from one time zone to another that results from the mismatch between our internal circadian cycles and our environment
- K-complex
- very high amplitude pattern of brain activity associated with stage 2 sleep that may occur in response to environmental stimuli
- latent content
- hidden meaning of a dream, per Sigmund Freud’s view of the function of dreams
- lucid dream
- people become aware that they are dreaming and can control the dream’s content
- manifest content
- storyline of events that occur during a dream, per Sigmund Freud’s view of the function of dreams
- meditation
- clearing the mind in order to achieve a state of relaxed awareness and focus
- melatonin
- hormone secreted by the endocrine gland that serves as an important regulator of the sleep-wake cycle
- meta-analysis
- study that combines the results of several related studies
- methadone
- synthetic opioid that is less euphorigenic than heroin and similar drugs; used to manage withdrawal symptoms in opiate users
- methadone clinic
- uses methadone to treat withdrawal symptoms in opiate users
- methamphetamine
- type of amphetamine that can be made from pseudoephedrine, an over-the-counter drug; widely manufactured and abused
- narcolepsy
- sleep disorder in which the sufferer cannot resist falling to sleep at inopportune times
- night terror
- sleep disorder in which the sleeper experiences a sense of panic and may scream or attempt to escape from the immediate environment
- non-REM (NREM)
- period of sleep outside periods of rapid eye movement (REM) sleep
- obstructive sleep apnea
- sleep disorder defined by episodes when breathing stops during sleep as a result of blockage of the airway
- opiate/opioid
- one of a category of drugs that has strong analgesic properties; opiates are produced from the resin of the opium poppy; includes heroin, morphine, methadone, and codeine
- parasomnia
- one of a group of sleep disorders characterized by unwanted, disruptive motor activity and/or experiences during sleep
- physical dependence
- changes in normal bodily functions that cause a drug user to experience withdrawal symptoms upon cessation of use
- pineal gland
- endocrine structure located inside the brain that releases melatonin
- psychological dependence
- emotional, rather than a physical, need for a drug which may be used to relieve psychological distress
- rapid eye movement (REM) sleep
- period of sleep characterized by brain waves very similar to those during wakefulness and by darting movements of the eyes under closed eyelids
- REM sleep behavior disorder (RBD)
- sleep disorder in which the muscle paralysis associated with the REM sleep phase does not occur; sleepers have high levels of physical activity during REM sleep, especially during disturbing dreams
- restless leg syndrome
- sleep disorder in which the sufferer has uncomfortable sensations in the legs when trying to fall asleep that are relieved by moving the legs
- rotating shift work
- work schedule that changes from early to late on a daily or weekly basis
- sleep
- state marked by relatively low levels of physical activity and reduced sensory awareness that is distinct from periods of rest that occur during wakefulness
- sleep apnea
- sleep disorder defined by episodes during which breathing stops during sleep
- sleep debt
- result of insufficient sleep on a chronic basis
- sleep rebound
- sleep-deprived individuals will experience shorter sleep latencies during subsequent opportunities for sleep
- sleep regulation
- brain’s control of switching between sleep and wakefulness as well as coordinating this cycle with the outside world
- sleep spindle
- rapid burst of high frequency brain waves during stage 2 sleep that may be important for learning and memory
- sleepwalking
- (also, somnambulism) sleep disorder in which the sleeper engages in relatively complex behaviors
- stage 1 sleep
- first stage of sleep; transitional phase that occurs between wakefulness and sleep; the period during which a person drifts off to sleep
- stage 2 sleep
- second stage of sleep; the body goes into deep relaxation; characterized by the appearance of sleep spindles
- stage 3 sleep
- third stage of sleep; deep sleep characterized by low frequency, high amplitude delta waves
- stimulant
- drug that tends to increase overall levels of neural activity; includes caffeine, nicotine, amphetamines, and cocaine
- sudden infant death syndrome (SIDS)
- infant (one year old or younger) with no apparent medical condition suddenly dies during sleep
- suprachiasmatic nucleus (SCN)
- area of the hypothalamus in which the body’s biological clock is located
- theta wave
- type of brain wave characteristic of the end of stage 1 NREM sleep, which has a moderately low amplitude and a frequency of 4–7 Hz
- tolerance
- state of requiring increasing quantities of the drug to gain the desired effect
- wakefulness
- characterized by high levels of sensory awareness, thought, and behavior
- withdrawal
- variety of negative symptoms experienced when drug use is discontinued