PSYC 1010 Lecture Notes - Hypnic Jerk, Slow-Wave Sleep, Lucid Dream
Variations in Consciousness
In the 1930’s the electroencephalogram was invented. It picks up brain waves (brain activity), by
detecting the electromagnetic radiation with electrodes on the head. After experimentation, it was
discovered that there are three types of brain waves, corresponding to the five stages of sleep.
Stages of Sleep
Theta sleep waves are prominent
Hypnic jerk: twitching
Mixed EEG activity – sleep spindles
Stage 3 & Stage 4
Progressively more delta waves – slow-wave sleep (SWS)
In stage 3 delta waves occur less than 50% of the time
In stage 4 delta waves occur more than 50% of the time
Sleep walking occurs during deep sleep. Sonabulism is the official term for sleep walking.
Rapid Eye Movement (REM) sleep
Low voltage, high-frequency waves
EEG patterns resemble those of people who are awake
Breathing is choppy and heart rate fluctuates
It’s difficult to awaken the person
Motor activity is practically eliminated, and the person is almost paralyzed
Paradoxical sleep: The internal organs are quite active, while the body seems paralyzed
Lucid Dreaming: Being aware that you are dreaming, and therefore can control the dream.
Sequence of Stages of Sleep
Most SWS occurs early in the night.
Most REM sleeps occurs later in the night with each succeeding REM period being longer than the
Theories for Why We Sleep
1. Sleep has a restorative function allowing us to recover from physical and mental exertion during
A) Slow wave sleep is implicated in the restoration process.
B) Growth hormone is released during slow wave sleep.
2. Sleep is viewed as part of a circadian rhythm that developed through evolution. Feeling sleepy
at night is programmed into us because it enforces inactivity at night, thus promoting survival.
Ultradian Rhythms: 90 min rest/activity cycles
Complete Sleep Deprivation: No sleep at all
Partial Deprivation (sleep restriction): Less sleep than needed
Selective Deprivation: Deprivation of certain stages of sleep. Stage rebound can occur, so that you make
up for the stage of sleep that you missed. If you missed an entire night of sleep, then stage 4 is the most
Functions of Dreams
1. Dreaming is considered a form of wish-fulfillment.
2. Problem solving view.
3. Activation-Synthesis Hypothesis.
4. Dreams consolidate memory.
5. REM may be important in the development of brain neurons.