Infradian and ultradian rhythms

Question 1

how is the menstrual cycle an infradian rhythm?

Answer 1

• governed by monthly hormone change
• atypical cycle is 28 days with different stages
• cycle is endogenous, but influenced by exogenous facts like other women

Question 2

what was the procedure of the menstrual cycle study (infradian rhythms effected by extraneous factors)

Answer 2

• McClintock (98) show how cycles can synchronise though pheromones
• 29 women with irregular periods - pheromones gathered from 9 women at different stages in cycle
• pad treated with alcohol then put on upper lip of women

Question 3

what were the findings of the menstrual cycle study (infradian)

Answer 3

McClintock found 68% of the women experienced changes to cycle bringing them closer to the “odor donor”

Question 4

+ evolutionary basis of the mestrual cycle

Answer 4

• synchrony is evolutionary as it was good for babies to be born at the same time to be cared for collectively (increase survival)
• however it seems synchrony was avoided evolutionary as if all women were synchronised it would create too much competition 9less fit offspring)

Question 5

• methodical limitation of synchrony in the menstrual cycle study

Answer 5

• many confounding variable scan affect an already irregular cycle like stress and diet
• uses small sample and relies on self report of women cycles

Question 6

how is seasonal affective disorder (SAD) an infradian rhythm?

Answer 6

• depressive disorder triggered in the winter months (classified in DSM-5)
• circannual rhythm as its yearly, circadian as it cam be caused by prolonged darkness
• hormone melatonin secreted for longer in the winter
  linked to serotonin which can cause depression

Question 7

how is sleep an ultradian rhythm?

Answer 7

• 5 stages of sleep cycle that spans about 90 minutes
• cycle continues through the night
• each stage had different brain waves (monitored with EEG)

Question 8

what is stage 1 and 2 of the sleep cycle?

Answer 8

• sleep escalator - light sleep, easily woken
• alpha waves patterns that are slower and more rhythmic
  (slower as sleep becomes deeper/ delta)

Question 9

what are stages 3 and 4 of the sleep cycle?

Answer 9

• even slower delta waves with greater amplitude

- deep sleep that difficult to wake

Question 10

what is stage 5 (REM) of the sleep cycle?

Answer 10

• body paralysed but brain activity speed u
• REM = rapid eye movement (denote fast jerky actions in eye)
• REM correlated with dreaming

Question 11

+ what was the lab study into sleep patterns?

Answer 11

• dement and Kleitman (57) monitored sleep of 9 people in lab with leg (control caffeine and alcohol)
• those woke during dream had very good recall of dreams
• test replicated with similar result but small sample size

(quantitative data good to analyse but lab means behaviour may not be natural)