biological rhythms: infradian and ultradian rhythms

• What was Stern and McClintock’s study?

  studied 29 women with a history of irregular periods. Samples of pheromones gathered from 9 of the women at diff stages of their menstrual cycles (cotton pad placed in their armpit). pads worn for 8 hours. pads treated with alcohol and frozen, rubbed on the upper lip of other participants. On day 1, pads from start of menstrual cycle applied to all 20 women, on day 2 were all given a pad from 2nd day of the cycle, and so on. found that 68% of women experienced changes to their cycle which brought them closer to cycle of their odour donor.
• What is seasonal affective disorder (SAD)?

  depressive disorder which has seasonal pattern of onset, diagnosed as a mental disorder in DSM-5. symptoms are persistent low mood, general lack of activity and interest in life. symptoms triggered in winter months when number of daylight hours becomes shorter. it’s particular type of infradian rhythm called a circannual rhythm as it‘s subject to a yearly cycle. but, can also be classed as a circadian rhythm as experience of SAD due to disruption of the sleep/wake cycle and can be attributed to prolonged periods of darkness during winter.
• What are the stages of sleep?

  5 stages that occur in a 90-minute cycle:

  Stages 1 and 2: Alpha waves and sleep spindles.

  Stages 3 and 4: Deep sleep, delta

  waves.

  Stage 5: REM sleep, theta waves.