ultradian rhythms Flashcards
(15 cards)
What are ultradian rhythms?
Ultradian rhythms are biological rhythms that occur more than once in 24 hours, such as the stages of human sleep.
How long does a typical sleep cycle last?
About 90 minutes.
What is the structure of a full sleep cycle?
The cycle includes four stages of NREM (light to deep sleep) followed by REM (rapid eye movement) sleep, and this sequence repeats through the night.
What characterises stages 1 and 2 of the sleep cycle?
These are light sleep stages where brain waves slow down from alpha to theta waves.
What characterises stages 3 and 4 of the sleep cycle?
These are deep sleep stages, also called slow wave sleep, dominated by slow delta waves. It’s difficult to wake someone during these stages.
What happens in stage 5 of the sleep cycle?
This is REM sleep, where brain activity resembles that of an awake person, dreaming occurs, and the body is paralysed to prevent acting out dreams.
How many sleep cycles does a person typically go through per night?
Up to five full sleep cycles.
What did Kleitman refer to the 90-minute sleep cycle as?
The Basic Rest Activity Cycle (BRAC).
What did Tucker et al. (2007) study in relation to sleep?
They studied 11 participants over 11 days and nights in a controlled lab to assess sleep patterns and found large individual differences.
What conclusion did Tucker et al. (2007) draw?
Differences in sleep patterns are likely biologically determined rather than due to situational factors, supporting the idea of individual variation in ultradian rhythms.
Why was the Tucker et al. (2007) study considered strong evidence for biological factors?
Because it was conducted in a tightly controlled lab setting, ruling out environmental factors like room temperature or sleep hygiene.
What is a key limitation of research into sleep cycles like the Tucker et al. study?
The artificial lab environment and invasive equipment (e.g., monitors) may affect typical sleep patterns, reducing ecological validity.
How does low ecological validity affect research into ultradian rhythms?
It may lead to results that do not accurately reflect natural sleep behaviour, limiting the generalisability of the findings.
What is a strength of using EEGs in sleep research?
EEGs provide objective, scientific data by recording distinct brain wave patterns across sleep stages.
What is a general evaluation point of controlled laboratory research into ultradian rhythms?
While lab studies offer control and objective data, they may not reflect real-life sleep due to artificial settings and potential participant discomfort.
