Lesson 12 - Biological Rhythms

Question 1

Infradian Rhythms

Answer 1

Last longer than 24 hours e.g. menstrual cycle and seasonal affective disorder.

Question 2

The Menstrual Cycle

Answer 2

Regulated by hormones promoting ovulation or stimulating the uterus for fertilisation. Halfway through ovulation begins, after the ovulatory phase, progesterone increases in preparation for a possible embryo.

Question 3

When Does Ovulation Begin

Answer 3

When oestrogen is at its highest (halfway through).

Question 4

Menstrual Cycle Strengths

Answer 4

Cave Study
Cycle Based On Odour
Feminised Faces

Question 5

Cave Study (+)

Answer 5

Reinberg - Examined woman who spent 3 months in a cave with only a small lamp, causing her cycle to shorten to 25.7 days meaning it’s affected by light.

Question 6

Cycles Based On Odour etc (+)

Answer 6

Russel Et Al - Found cycles can syncrhonise based on odour, sweat samples of one group were rubbed on the upper lip of another group and despite being separate they synced - external factors should always be taken into consideration.

Question 7

Feminised Faces (+)

Answer 7

Penton Volk Et - Found woman had a preference for feminised faces at the least fertile stage of the cycle and men at the most fertile meaning it affects sexual behaviour.

Question 8

Seasonal Affective Disorder

Answer 8

Where there’s season variation in mood. It’s a yearly cycle and melatonin is partly responsible.

Question 9

Example Of Seasonal Affective Disorder

Answer 9

Depressed in winter

Question 10

How Is Melatonin Responsible

Answer 10

A lack of light in winter results in increased melatonin, which is linked to depressive systems.

Question 11

Seasonal Affective Disorder Strengths

Answer 11

Country Validity
Practical Application

Question 12

Country Validity (+)

Answer 12

Terman - SAD is more common in countries where winter nights are longer. 10% of people in North USA and 2% in South USA suffered from SAD, showing it’s selected by light and therefore melatonin.

Question 13

Practical Application (+)

Answer 13

Phototherapy cures SAD, it rests melatonin levels which regulates serotonin and improves symptoms for 60% of patients.

Question 14

Seasonal Affective Disorder Weakness

Answer 14

Placebo Affect

Question 15

Placebo Affect (-)

Answer 15

30% of participants showed improvements with a pretend ‘negative generation’, suggesting phototherapy may just work due to the placebo affect.

Question 16

Phototherapy

Answer 16

A Lightbox that stimulates strong levels of light in the morning and evening to regulate melatonin levels.

Question 17

Exogenous Zeitgebers

Answer 17

External factors/cues affecting internal biological rhythms.

Question 18

Ultradian Rhythms

Answer 18

Are less than 24 hours, and can be found in human sleep patterns.

Question 19

The Human Sleep Cycle

Answer 19

Alternates between REM & NREM, the cycle goes light sleep –> deep sleep –> REM sleep and circles every 90 mins.

Question 20

REM Sleep

Answer 20

Where brain waves speed up and dreaming occurs.

Question 21

Stages Of Sleep

Answer 21

1 & 2 = Light Sleep
3 & 4 = Deep Sleep
5 = Rem Sleep

Question 22

1 & 2 - Light Sleep

Answer 22

Brain wave patterns are slower and more rhythmic, starting with alpha and ending with theta waves.

Question 23

3 & 4 - Deep Sleep

Answer 23

Slow waves, associated with deep waves.

Question 24

5 - REM Sleep

Answer 24

It’s difficult to wake someone up, associated with slower delta waves

Question 25

BRAC

Answer 25

Basic Rest Activity Cycle

Question 26

Kleitman

Answer 26

Referred to the 90 minute sleep cycle as BRAC, which continues when you’re awake instead of sleeping going from alertness to psychologically fatigued.

Question 27

Ultradian Rhythms Case Study

Answer 27

Dement & Kleitman studied brain activity of 9 adults using EEG in a sleep lab, alcohol and caffeine was controlled, EEG patterns within each sleep stage, correlated with dreaming.

Question 28

Potential Issue With Dement & Kleitman

Answer 28

The study has a small sample size but the results have been replicated suggesting there’s a reliable link.

Question 29

Ultradian Rhythms Strengths

Answer 29

Research Support
Pianists

Question 30

Research Support (+)

Answer 30

Dement and Kleitman’s study

Question 31

Errisson Et Al (+)

Answer 31

Found a group of elite violinists practice for 90 mins and slept after, the best ones sleeping longer, supporting the BRAC.

Question 32

Ultradian Rhythms Weaknesses

Answer 32

Difficult To Generalise

Question 33

Difficult To Generalise (-)

Answer 33

Tucher Et Al studied participants over 11 days and each sleep stage had different characteristics suggesting there’s possibly biological differences that influence the study.