Consciousness
The process by which the brain creates a model of internal and external experience
Cognitive neuroscience
An interdisciplinary field involving cognitive psychology, neurology, biology, computer science, linguistics, and specialists from other fields who are interested in the connection between mental processes and the brain
Nonconscious processes
Any brain process that does not involve conscious processing including both preconscious memories and unconscious processes.
Preconscious memories
Information that is not currently in consciousness but can be recalled to consciousness voluntarily or after something calls attention to them
Unconscious
In classic Freudian theory, a part of the mind that houses memories, desires, and feelings that would be threatening if brought to consciousness. Many modern cognitive psychologists view the unconscious in less sinister terms, merely as a collection of me
Daydreaming
A common (and quite normal) variation of consciousness in which attention shifts to memories, expectations, desires, or fantasies and away from the immediate situation
Circadian rhythms
Physiological patterns that repeat approximately every 24 hours - such as sleep - wakefulness cycle
REM sleep
A stage of sleep that occurs approximately every 90 minutes, marked by bursts of rapid eye movements occurring under closed eyelids. REM sleep periods are associated with dreaming.
Non-REM sleep (or NREM sleep)
The recurring periods, mainly associated with the deeper statges of sleep, when a sleeper is not showing rapid eye movements
Sleep paralysis
A condition in which a sleeper is unable to move any of the voluntary muscles, except those controlling the eyes. Sleep paralysis normally occurs during REM sleep
REM rebound
A condition of increased REM sleep cause by REM-sleep deprivation
Sleep debt
A sleep deficiency caused by not getting the amount of sleep that one requires for optimal functioning.
Manifest content
The story line of a dream, taken at face value without interpretation
Latent content
The symbolic meaning of objects and events in a dream. Latent content is usually an interpretation based on Freud's psychoanalytic theory or one of its variants. The latent content of a dream involving clocks might involve fear of the menstrual cycle and,
Activation-synthesis theory
The theory that dreams begin with random electrical activation coming from the brain stem. Dreams, then, are the brain's attempt to make sense of - to synthesize - this random activity.
Insomnia
The most common of sleep disorders - involving insufficient sleep, the inability to fall asleep quickly, frequent arousals, or early awakenings
Sleep apnea
A respiratory disorder in which the person intermittently stops breathing many times while asleep
Night terrors
Deep sleep episodes that seem to produce terror, although any terrifying mental experience (such as a dream) is usually forgotten upon awakening. Night terrors occur mainly in children.
Narcolepsy
A disorder of REM sleep, involving sleep-onset REM periods and sudden daytime REM-sleep attacks usually accompanied by cataplexy
Hypnosis
An induced state of awareness, usually characterized by heightened suggestibility, deep relaxation, and highly focused attention
Meditation
A state of consciousness often induced by focusing on a repetitive behavior assuming certain body positions, and minimizing external stimulation. Meditation may be intended to enhance self-knowledge, well-being, and spirituality
Psychoactive drugs
Chemicals that affect mental processes and behavior by their affects on the brain
Hallucinogens
Drugs that create hallucinations or alter perceptions of the external environment and inner awareness.
Opiates
Highly addictive drugs, derived from opium, that can produce a profound sense of well-being and have strong pain-relieving properties
Depressants
Drugs that slow down mental and physical activity by inhibiting transmission of nerve impulses in the central nervous system
Stimulants
Drugs that arouse the central nervous system, speeding up mental and physical responses
Tolerance
The reduced effectiveness a drug has after repeated use
Physical dependence
A process by which the body adjusts to, and comes to need, a drug for its everyday functioning
Addiction
A condition in which a person continues to use a drug despite its adverse effects - often despite repeated attempts to discontinue using the drug. Addiction may be based on physical or psychological dependence
Withdrawal
A pattern of uncomfortable or painful physical symptoms and cravings experienced by the user when the level of drug is decreased or the drug is eliminated
Psychological dependence
A desire to obtain or use a drug, even though there is no physical dependence