Variation in Consciousness
The awareness of internal and external stimuli. Sensing those things in the world, around us, and
The Nature of Consciousness
● Subjective and Private
● Dynamic: Ever-changing, Constant flux
○ William James: Stream of consciousness
○ Sense of self
The Electroencephalogram (EEG)
● Beta Waves (4-8 cycles/sec.) Light sleep
● Alpha Waves (8-12 cycles/sec.) Rest, relax
● Theta Waves (13-25 cycles/sec.)Alert, awake.
● Delta Waves (<4 cycles/sec.) Deep sleep
● Biological Rhythms
● Periodic fluctuations in Physiological functions
○ B.P. (Blood Pressure)
○ Hormones (Secretion)
○ Core Body Temp
● As body cools down, tend to fall asleep.As body heats up, tend to wake up.
● Exposure to light affects activity in Suprachiasmatic Nucleus [SCN] (Hypothalamus)
● Signals to Pineal Gland
● Increase or decrease Melatonin
SCN neurons are active during the day, melatonin is reduced, increases body temperature and
SCN neurons not active during the night, melatonin is increased, easier transition to
● Depends on which direction you traveled.
○ Flying West easier than East.
~18% on rotating job shifts.
The Stages of Sleep
● Stage 1 Sleep: Theta waves prominent
● Stage 2 sleep: Sleep Spindles and Mixed EEG Activity
○ Sleep Spindles: short 1-2 second bursts of rapid activity.
● Stage 3 and Stage 4 Sleep: ○ Slow-wave Sleep
■ Progressively More Delta Waves
■ Stage 3: Delta waves appear
■ Stage 4: Delta waves dominant
● Awake: Low-voltage. High frequency beta waves
● REM Sleep: Low-voltage, High frequency beta waves (most of our dreaming)
● During dreaming, physiological arousal can reach daytime levels
Repeating the Cycle
● 8 hours daily
● Impaired attention, reaction time, decision making
● Traffic accidents
● Workplace accidents
● Health Problems
There’s a cellular waste product, adenosine, how our body needs to purge and restore.
During sleep, adenosine decreases.