Psychology Lecture 17
Cicadian Rhythms, Consciousness, Sleep Stages
What are the daily rhythms affecting humans?
What is consciousness?
What happens when we sleep?
o Daily cycles
o 25 hour clock
Time frame that takes people to do these things
Peak levels in late afternoon
Best time for physical tasks
o Suprachiasmatic nucleus
Clump of cells above optic chiasm
Internal timing mechanism in hypothalamus
Daylight stimulates the SCN, which inhibits production of melatonin in pineal
Photosensitive ganglion cells are stimulated and melanopsin (blue light)
is also seen
darkness removes the inhibition, resulting in more melatonin, therefore we feel
o Jet lag and shift work
o Phase advance more difficult than phase delay
For example, flying from Vancouver to Halifax is more problematic rather than
the other way around
o Take melatonin?
Jury is still out, don’t know if it works or is safe
More effective for delay
Probably works by relieving daytime fatigue
o Jet lag avoidance
Hydrate on plane
Get up and stretch