Your awareness of everything that is going on around you and inside your own head at any given movement, which you use to organize your behavior.

• Consciousness

• Circadian Rhythm

• Insomnia

• Hypnosis

Occurs when there is a shift in the quality or pattern of your mental activity. Thoughts may become fuzzy, disorganized and you may feel less alert, or your thoughts may take bizarre turns, as they so often do in dreams.

• Altered State of Consciousness

• Waking Consciousness

• Hypnosis

• Narcolepsy

The sleep-wake cycle.

• Circadian Rhythm

• Sleep Deprivation

• Microsleep

• Rapid Eye Movement (REM) Sleep

A relatively psychologically active type of sleep when most of a person’s dreaming takes place; voluntary muscles are inhibited, making the person move very little.

• Rapid Eye Movement (REM) Sleep

• Non-REM Sleep

Spans from lighter stages to a much deeper, more restful kind of sleep; the person’s body is free to move around in this stage.

• Non-REM Sleep

• Rapid Eye Movement (REM) Sleep

A machine that allows scientists to record the brain-wave activity as a person passes through the various stages of sleep and to determine what type of sleep the person has entered.

• Electroencephalography (EEG)

• Positron Emission Tomography (PET) Scan

• Computed Tomography (CT or CAT) Scan

• Magnetic Resonance Imaging (MRI)

Which of the following is not a brain-wave pattern during sleep?

• Gamma Waves

• Beta Waves

• Alpha Waves

• Theta Waves

The inability to get to sleep, stay asleep, or get a good quality of sleep.

• Insomnia

• Sleep Apnea

• Narcolepsy

• Microsleep

A type of snoring in which the person stops breathing for 10 seconds or more.

• Sleep Apnea

• Narcolepsy

• Microsleep

• Insomnia

A kind of “sleep seizure” in which the person may slip suddenly into REM sleep during the day, especially when the person experiences strong emotions. Another symptom is excessive daytime sleepiness that results in the person falling asleep throughout the day at inappropriate times and in inappropriate places.

• Narcolepsy

• Sleep Apnea

• Insomnia

• Hypnosis