Ultradian rhythms Flashcards
What are ultradian rhythms?
A type of biological rhythm with a frequency of more than 1 cycle in 24 hours
What is an example of an ultradian rhythm?
Stages of sleep
What are brain waves made of?
Rise and fall, frequency and amplitude
What is frequency?
The time between each peak
What is amplitude?
The height of each peak - amount of electrical activity
What are sleep stages?
Start with a period of NREM sleep, going gradually down the sleep staircase from stage 1 (lightest sleep) to stage 2, 3 and spend about 10-15 mins in each stage before stage 4
How many stages of sleep are there?
5
What is the first stage of sleep?
Light sleep - when a person can be easily waken
What waves are present in stage 1?
Alpha waves
What is the frequency and amplitude of alpha waves?
High frequency and low amplitude
What is the second stage of sleep?
The same as stage 1
What are the waves in second stage sleep?
Alpha waves but with random changes in pattern - sleep spindles
What is the 3rd and 4th stage of sleep?
Deep sleep of slow wave sleep (SWS) and is difficult to wake someone
What are the waves in 3rd and 4th stage of sleep?
Delta waves
What are delta waves?
Thy have lower frequency and higher amplitude
What is the 5th stage of sleep?
REM (rapid eye movement ) - the body is paralysed but brain activity is similar to that of an awake brain
What brain waves are produced in the 5th stage of sleep?
Theta waves and the eyes occasionally move
When do dreams occur?
Mostly in REM sleep but sometimes in deep sleep
What is research evidence for sleep stags?
Dement and Kleitman who used EEG to distinguish stages of sleep
What are methodological issues with sleep studies?
Extraneous variables such as noise and may not represent ordinary sleep patterns,
What are methodological strentghs of sleep studies?
Distinct cyclical pattern of brain activity confirmed in replications and use of EEG is objective
What are real life applications of sleep studies?
Improved understanding of how slow wave sleep reduces with age and explains issues in old age such as reduced alertness and daytime naps
What are individual differences with sleep studies?
Differences are biologically determined so can’t describe normal sleep and Tucker et al. found differences in duration of each sleep stage
