PsychSim 5: EEG and Sleep Stages

Name: Leanne Gresch Section: 3

Date: 2-12-14

This activity provides an explanation of the measurement of brain activity, as well as the presence of different sleep patterns and their respective functions.

EEG
How is the brain’s electrical activity recorded?

The electrical activity recorded at the reference location (usually on the ear lobe or just behind the ear) in generally subtracted from the electrical activity recorded at the target location(s). This means that, at a minimum, two electrodes are required to measure EEG. Typically the EEG includes recordings from three to eight locations so that activity of various reigons of the brain can be compared.

Stages of Sleep
Complete the following table:

Characteristic EEG Pattern

Stage 1 A transition from wakefulness into sleep.

Stage 2 Brief bursts of brain activity in the midst of overall slowing of the EEG waves; At this point, the person is truly asleep.

Stage 3 Low-frequency (3 peaks/ second) high amplitude waves called delta waves, which make up 10% to 50% of the tracings at this stage.

Stage 4 Deepest stage of sleep, the tracings consist almost entirely of delta waves.

REM Sleep Almost complete relaxation except for the eye muscles, which are very active.

Sleep Thoughts vs. True Dreams

If people have vivid, realistic dreams during REM sleep, why don’t they act out those dreams, perhaps injuring themselves or others?

Fortunately, during REM sleep most motor neurons are inhibited, producing a kind of paralysis that keeps people from hurting themselves during a dream.

Purpose of Sleep
What are the two main purposes of sleep?

It reduces our energy expenditures so that the body's resources can be mobilized for tissue repairs and growth. Sleep also