Question | Answer |
consciousness | The subjective awareness of ourselves and our environment. |
biological rhythms | Regularly occurring cycles of behaviors caused by biological factors. |
circadian rhythm | The biological cycle that guides the daily waking and sleeping in many animals. |
rapid eye movement (REM) sleep | A sleep stage characterized by the presence of fast eye movements and dreaming. |
non-rapid eye movement (non-REM) sleep | A deep sleep, characterized by very slow brain waves, which is further subdivided into three substages, labeled as stages N1, N2, and N3. |
insomnia | A sleep disorder that involves persistent difficulty falling or staying asleep. |
sleep apnea | A sleep disorder characterized by pauses in breathing that last at least 10 seconds during sleep. |
narcolepsy | A disorder characterized by extreme daytime sleepiness with frequent episodes of “nodding off.” |
dreams | The succession of images, thoughts, sounds, and emotions that passes through our minds while sleeping. |
psychoactive drug | A chemical that changes our states of consciousness, and particularly our perceptions and moods. |
tolerance | An increase in the dose of a drug required to produce the same effect. |
dependence | The need to use a drug or other substance regularly. |
withdrawal | Negative experiences that accompany reducing or stopping drug use, including physical pain and other symptoms. |
addiction | When the user powerfully craves the drug and is driven to seek it out, over and over again, no matter what the physical, social, financial, and legal cost. |
stimulant | A class of psychoactive drugs that operate by blocking the reuptake of dopamine, norepinephrine, and serotonin in the synapses of the central nervous system. |
caffeine | A bitter psychoactive drug found in the beans, leaves, and fruits of plants. |
nicotine | A psychoactive drug found in tobacco products. |
cocaine | An addictive drug obtained from the leaves of the coca plant. |
amphetamine | A stimulant that produces increased wakefulness and focus, along with decreased fatigue and appetite. |
depressant | A class of psychoactive drugs that reduce the activity of the CNS. |
alcohol | A colorless liquid, produced by the fermentation of sugar or starch, that is the intoxicating agent in fermented drinks. |
barbiturates | A family of depressants that are commonly prescribed as sleeping pills and painkillers. |
benzodiazepines | A family of depressants used to treat anxiety, insomnia, seizures, and muscle spasms. |
opioids | A family of chemicals that increase activity in opioid receptor neurons in the brain and in the digestive system, producing euphoria, analgesia, slower breathing, and constipation. |
opium | The dried juice of the unripe seed capsule of the opium poppy. |
morphine | A powerful and addictive drug derived from opium. |
heroin | A powerful and addictive drug derived from opium. |
codeine | A powerful and addictive drug derived from opium. |
hallucinogens | A family of psychoactive drugs that alter sensation and perception. |
hypnosis | A trance-like state of consciousness, usually induced by a procedure known as hypnotic induction, which consists of heightened suggestibility, deep relaxation, and intense focus. |
sensory deprivation | Intentional reduction of stimuli affecting one or more of the five senses, with the possibility of resulting changes in consciousness. |
meditation | To techniques in which the individual focuses on something specific, such as an object, a word, or one’s breathing, with the goal of ignoring external distractions, focusing on one’s internal state, and achieving a state of relaxation and well-being. |