Biopsychology(ultradian and infradian rhythms)

Question 1

What is an infradian rhythm?

Answer 1

A biological rhythm that have durations of over 24 hours, may be weekly, monthly or annually. Menstrual cycle

Question 2

What is an ultradian rhythm?

Answer 2

A biological rhythm that have durations of less than 24 hours, such as the stages of sleep that occur through the night.

Question 3

Use of REM and NREM in the ultradian rhythm -

Answer 3

The rhythm found in human sleep follows a pattern of alternating REM (rapid eye movement) and NREM (non-rapid eye movement) sleep.

Question 4

How long does the cycle repeat itself (ultradian rhythm)

Answer 4

90-100 minutes

Question 5

How many stages in the sleep wake cycle?

Answer 5

1 to 5

Question 6

How do we know about these cycles from sleep?

Answer 6

Use of electrical activities of the brain, with each stage showing a distinct pattern.

Question 7

Stage 1:

Answer 7

light sleep, muscle activity slows down, slight decrease in body temperature.

Question 8

Stage 2:

Answer 8

breathing pattern and heart rate slows, decrease in body temperature.

Question 9

Stage 3:

Answer 9

Deep sleep begins, brain begins to generate slow delta waves.

Question 10

Stage 4:

Answer 10

Limited muscle activity, very deep sleep, brain produces delta waves.

Question 11

Stage 5:

Answer 11

REM, brain waves are sped up and dreaming occurs, muscles relax and heart rate increases, breathing rapid and shallow.

Question 12

Infradian rhythm - (menstrual cycle)

Answer 12

A woman’s menstrual cycle as it lasts longer than 24 hours and around a month, can last as low as 23 days but may end at 36 days. The menstrual cycle is regulated hormones which stimulate ovulation and the lining of the uterus.

Question 13

There are individual differences for the ultradian rhythm (sleep stages) -

Answer 13

Differences in the sleep pattern are usually governed by non-biological factors (sleep hygiene), however Tucker’s study suggests that these differences a large in part of biological determination.

Participants were studied over a 11 day and night in strictly controlled laboratory environments, the researchers assessed the time it took to fall asleep, sleep duration and amount of time in each stage of the sleep cycle. Found large individuals differences in the characteristics. Which showed consistently across 8 nights, they showed considerable differences across stages 3 and 4 therefore suggesting that differences were not driven by circumstances but were partly biologically driven.

Question 14

The menstrual cycle and the role of exogenous cues -

Answer 14

The menstrual cycle is normally governed by the endogenous system of the pituitary gland which are used to regulate the infradian rhythm, but it can be controlled by exogenous cues. Women’s menstrual cycle tend to synchronise depending on their environment, for example in one study daily samples of sweat were collected from one group of women and rubbed onto the upper lips in a second group, the groups were then kept separate but their cycles synchronised. Suggesting the synchronisation can be suggested by pheromones which act similarly to hormones but come from outside the body through excretion.