Biological Psychology, 5e.ppt

Biological Rhythms,Sleep, and Dreaming
14 Biological Rhythms, Sleep, and Dreaming
Biological Rhythms
Many Animals Show Daily Rhythms in Activity
The Hypothalamus Houses an Endogenous Circadian Clock
Animals Use Circannual Rhythms to Anticipate Seasonal Changes
14 Biological Rhythms, Sleep, and Dreaming
Sleeping and Waking
Human Sleep Exhibits Different Stages
The Sleep of Different Species Provides Clues about the Evolution of Sleep
Our Sleep Patterns Change across the Life Span
Manipulating Sleep Reveals an Underlying Structure
14 Biological Rhythms, Sleep, and Dreaming
What are the Biological Functions of Sleep?
At Least Four Interacting Neural Systems Underlie Sleep
Sleep Disorders Can Be Serious, Even Life-Threatening
Many Animals Show Daily Rhythms in Activity
Circadian rhythms are those functions of a anism that display a rhythm of about 24 hours.
Rhythms may be behavioral, physiological, or biochemical.
Diurnal—active during the light
Nocturnal—active during the dark
Figure How Activity Rhythms are Measured (Part 1)
Many Animals Show Daily Rhythms in Activity
Circadian rhythms are generated by an endogenous (internal) clock.
A free-running animal is maintaining its own cycle with no external cues, such as light.
The period, or time between essive cycles, may not be exactly 24 hours.
Figure How Activity Rhythms are Measured (Part 2)
Many Animals Show Daily Rhythms in Activity
A phase shift is the shift in activity in response to a synchronizing stimulus, such as light or food.
Entrainment is the process of shifting the rhythm.
The cue that an animal uses to synchronize with the environment is called a zeitgeber—“time-giver”
The Hypothalamus Houses an Endogenous Circadian Clock
The biological clock is in the suprachiasmatic nucleus (SCN)—located above the optic chiasm in the hypothalamus.
Studies showed that circadian rhythms were disrupted in SCN-lesioned animals.
Isolated SCNs can maintain electrical activity synchronized to the pre