Definitions

Rapid Eye Movement in sleep was first documented in 1952 by Nathaniel Kleitman and Gene Aserinsky.  According to Dement, they discovered it by accident, while studying slow eye movements at sleep onset.  Rapid eye movement is highly coordinated, and appears identical to a waking person's eye movements.  Kleitman, Aserinksy, and Dement would later conclude that REM is associated with dreaming.

Sources:

Dement, The Promise of Sleep

Theory of two independent, and opposing, regulators of sleep and wakefulness in the human body.  The biological clock is responsible for, among many other things, keeping us awake.   The sleep drive promotes sleep.   When clock-dependent alerting is very high, such as in the mid-morning and the early evening, it is very difficult to fall asleep, unless there is significant sleep debt.  However, when the clock's alerting slacks off, which it does typically in the mid-afternoon, the sleep drive will take over, especially if there is a large sleep debt.  The opponent process model explains not only why the mid-afternoon siesta can be so hard to resist, but also underlies the phenonomen of jet lag. 

Source:

Dement, The Promise of Sleep 

Unpleasant, even terrifying dream that occurs in REM sleep.  Nightmares trigger a range of emotional response including fear, anxiety, anger, and sadness.  The etymology of the word reflects a series of shifts in its meaning.  Around 1300 a nightmare was "an evil female spirit afflicting sleepers with a feeling of suffocation,"  a compound of "night" and "mare"-- Old English for a goblin or incubus that sits on the chest of the sleeper.  This was also known as "Old Hag Syndrome," where the nightmare was personified as an old woman suffocating the sleeper.  "Old Hag" may have come from the phenomenon of REM muscle paralysis, which, if dimly perceived by the sleeper, can give rise to dreams of being unable to move in the face of danger.  In the mid-16th century, the meaning of "nightmare" shifted from the demon to the dream it causes. 

Sources:

"Nightmare," Online Etymology Dictionary 

Caldwell, Sleep 

Parasomnia that typically afflicts children between the ages of two and five, although a small percentage of adults also suffer from them.  A person in the throes of a night terror will often sit up in bed and scream, eyes wide open.  However, a night terror is not a nightmare.  They do not occur during REM sleep, but rather during very deep sleep, so there is no accompanying dream content.  It is very difficult to wake the subject up in the middle of the episode, and usually the subject will have no recollection of the terror when awake.  Research suggests that in a night terror, the primitive parts of the brain--emotion and basic motor skills--are aroused, while the higher thinking functions remain asleep.   

Source:

Dement, The Promise of Sleep 

A sleep disorder in which the subject passes immediately into REM sleep, often during the daytime.  A narcoleptic episode is sometimes described as a "sleep attack."  Narcolepsy is characterized by extreme daytime drowsiness, cataplexy, and muscle weakness or paralysis.  An attack is often precipitated by a strong emotion, even laughter.  There is no cure for the disease at present.  Typical treatments involve stimulants and anti-depressants. 

Source:

Dement, The Promise of Sleep 

Electroencephalograph.  This is one of the primary ways that scientists study sleep.  The EEG measures the electrical activity of the brain, via electrodes attached to a subject's scalp.  Hans Berger is usually credited with its invention (c. 1920), although scientists had been experimenting with charting the electrical activity of the brain in the late 19th century.

Sources:

Dement, The Promise of Sleep

Lavie, The Enchanted World of Sleep 

The Multiple Sleep Latency Test, devised by Dement and his team at the Stanford Sleep Center, measures how long it takes a subject to fall asleep.  The test is limited to 20 minutes, and is administered every 2 hours during the daytime.  The MSLT is useful in charting sleep debt and its interaction with the biological clock. 

Source:

Dement, The Promise of Sleep 

Freudian terminology that is used to distinguish the actual dream from the dream's meaning. Manifest content is the dream as it is dreamed. The dream's latent content is the real meaning behind the dream, the meaning that the manifest content seeks to hide from the dreamer's conscious mind.

Source:

Freud, The Interpretation of Dreams

The experience of being aware that one is dreaming in the midst of a dream.  Some lucid dreamers are able to control aspects of their dreams as well.  Lucid dreaming has long been a practice of Buddhist dream yoga.  Lucidity in dreams would help the student grasp that all experience is illusion.  Western science is only just recently begun to explore the mechanics and the applications of lucid dreaming, although the phenomenon has been described in historical and religious texts since the 5th century.  

Sources:

Dement, The Promise of Sleep

LaBerge and Rheingold, Exploring the World of Lucid Dreaming 

When one's internal circadian rhythm is out of synch with external cues.  This is a phenonmenon more widely experienced since the age of jet travel.  If I leave Philadelphia at 7PM and arrive in Paris about 6 hours later, my body believes that it is 1AM.  However, for all of Paris, it is 7AM, and the day is just beginning.  It can take up to a full week to adjust one's internal clock to the new time, which means that even despite my enormous sleep debt, I may still suffer from jet lag at 3AM, when my body thinks its only 9PM. 

Source:

Dement, The Promise of Sleep 

Insomnia is not a single disorder, but rather a broad term used to indicate difficulty falling asleep or staying asleep for as long as one wishes. Dement considers it more a symptom than a disease. It is difficult for doctors to get much data on insomnia, because it is a self-diagnosed problem, though it is linked to other disorders, especially stress, psychological and emotional problems, and gastro-intestinal reflux. Insomnia's main danger is that it leads to uncontrollable daytime drowsiness, when the insomniac's sleep debt must finally be "paid."

Source:

Dement, The Promise of Sleep

Vivid hallucinations which occur during the onset of sleep (stage one, light sleep).  Often the hallucination is experienced as a seamless continuation of the sleeper's last waking sensory impressions. The term was first used by French sleep theorist Alfred Maury in 1848. 

Sources:

Lavie, The Enchanted World of Sleep 

Maury, Sleep and Dreams 

A dream that has access to a memory forgotten or inaccessible during waking consciousness. 

Source:

Freud, The Interpretation of Dreams 

A key element to Freud's method of dream interpretation.   In free association, the patient says everything that comes to mind in the retelling of a dream, no matter how trivial the detail.  It is critical for the patient to relax and suspend his or her critical thinking.  It is the analyst's role to study the series of associations, which will ultimately lead to the dream's meaning.  

Source:

Freud, The Interpretation of Dreams 

One of the three types of dreams in Tibetan Buddhist dream yoga.  Clear light dreams come only to the advanced practitioner.  In a clear light dream, the dreamer is not only lucid, but the dream self is indistinguishable from the dream.  “The clear light dream is not defined by the content of the dream, but is a clear light dream because there is no subjective dreamer or dream ego, nor any self in a dualistic relationship with the dream or the dream content” (Rinpoche 64).

Source:
Rinpoche, The Tibetan Yogas of Dream and Sleep   

One of the three types of dreams in the Tibetan Buddhist practice of dream yoga. In a dream of clarity, the dreamer may or may not be lucid (aware that she is dreaming), but the dream’s meaning will be clear. “In the dream of clarity, it is as if something is given to or found by the dreamer…” (Rinpoche 62).

Source:
Rinpoche, The Tibetan Yogas of Dream and Sleep

World-creating epoch in Aboriginal Australian cosmology.  During the Dreamtime, the ancestors created and cavorted about the landscape, before retiring into the earth.  The dreamtime is outside of linear time, but is accessible through dream, dance, vision, and trance.  

Source:
Tonkinson,  The Mardu Aborigines: Living the Dream in Australia’s Desert

Founded in the 4th century, B.C.E., the cult of Asclepius was named for the ancient Greek god of medicine and healing.  Asclepian priests ran healing centers that offered dream therapy for the sick.  Patients would spend a night in the temple, praying for a dream of the god.  In the morning, the priests would interpret the dream and recommend treatment.  The cult continued during Roman rule until the rise of Christianity in the late 5th century.  Asclepius was eventually assimilated into the cult of the saints, some of whom were considered dream healers.

Sources:

Miller, Dreams in Late Antiquity
Encyclopedia Mythica, “Asclepius”

Carl Jung’s notion of a blueprint of humanity that connects each individual to the whole of humankind across spacetime. The collective unconscious is the wellspring of the archetypes, and underlies the psychic forces that give rise to dreams.

Sources:

Jung, Dreams
Bulkeley, An Introduction to the Psychology of Dreaming

“Around (circa) a day (diem)”:  the daily cycle in the physiological processes of living things.  In sleep science, it refers to an organism’s internal pattern of sleep and wakefulness, not dependent upon external cues such as daylight.  

Sources:

Dement, The Promise of Sleep
Lavie, The Enchanted World of Sleep