Ultradian Rhythms

Question 1

What is an ultradian rhythm?

Answer 1

A rhythm that has less than 24 hours periodicity

Question 2

What is the main ultradian rhythm?

Answer 2

The different stages of sleep

Question 3

How are the stages of sleep measured?

Answer 3

By an EEG which measures brain waves

Question 4

How many stages of sleep are there?

Answer 4

5

Question 5

How long do all of the stages of sleep take?

Answer 5

90 minutes

Question 6

Outline the 5 stages of sleep

Answer 6

1 & 2 are light sleep (change in electrical electricity activity in the brain )
3 & 4 are slow wave sleep (SWS)
5 is REM sleep

Question 7

What characterises light sleep?

Answer 7

Alpha waves

Question 8

What characterises slow wave sleep?

Answer 8

Delta waves

Question 9

What occurs during slow wave sleep?

Answer 9

Biochemical processes like the production of growth hormones

Question 10

What characterises REM sleep?

Answer 10

Fast, desynchronised EEG activity resembling the waking brain

Question 11

What stages are NREM sleep?

Answer 11

The first 4

Question 12

What does BRAC stand for?

Answer 12

Basic Rest-Activity Cycle

Question 13

What is the BRAC?

Answer 13

The 90 minute cycle that occurs throughout the day

Question 14

What evidence is there for the BRAC?

Answer 14

Friedman & Fisher (1967)

Question 15

What does Friedman & Fisher (1967) show?

Answer 15

The existence of the BRAC

Question 16

Outline Friedman & Fisher (1967)

Answer 16

They observed eating and drinking behaviour in psychiatric patients over 6 hours and detected a clear 90 minute cycle

Question 17

What is the main research study for the different stages of sleep?

Answer 17

Kleitman & Dement (1957)

Question 18

Outline Kleitman & Dement (1957)

Answer 18

10 participants in a sleep lab for 61 nights, in which EEG readings were taken to determine the stage of sleep and thus woke them at different stages and asked about experiences and emotions. They found that during REM, 80-90% reported dreams in great detail. However, only 7% reported dreams during NREM and in deep sleep, reported confusion and thought they were dreaming but could not describe them. They displayed similar EEG, EMG, ECG & EOG patterns showing 90 minute cycles. Also, they showed progressively more REM and less deep sleep and that we have about 4 or 5 cycles every night

Question 19

Other than research evidence, what is another positive of the sleep cycles?

Answer 19

It has stood the test of time and is accepted by the scientific community

Question 20

What are 4 negative points about Kleitman & Dement (1957)?

Answer 20

1) Some studies contradict as they have found 70% report dreams in NREM sleep - but what constitutes a dream?
2) Small sample, mainly men - generalisability
3) Sleep lab not a real life setting so lacks ecological validity
4) Shows a close correlation between REM & dreaming but the nature of the relationship remains unclear - dreams may just be recalled easier in REM sleep than NREM because NREM is a deeper stage of sleep so it is just harder to recall?

Question 21

What is the importance of BRAC?

Answer 21

It is a form of timing biological processes in body unison

Question 22

What evidence is there for the importance of BRAC?

Answer 22

Klein & Armitage (1979)

Question 23

Outline Klein & Armitage

Answer 23

They found 90 minute rhythms during the day in cognitive vigilance with participants showing regular peaks and troughs in performance on spatial and verbal tasks