Ultradian Rhythms

Question 1

Basic rest activity cycle

Answer 1

During the daytime there is also a 90 minute cycle of rest followed by activity.

Friedman and fisher observed psychiatric patients over a 6 hour period and noted a clear pattern of 90 minutes between eating and drinking episodes

Question 2

Sleep stages

Answer 2

Stage 1 and 2:
Relaxed alpha and theta waves, heart rate slows, temp drops

Stage 3 and 4: DEEP SLEEP SWS
Delta waves, metabolic rate slows, growth hormone produced

REM sleep:
Associated with dreaming, brain and eyes active but body paralysed

One cycle takes 90 mins

Question 3

AO2 sleep stages

Answer 3

Dement and Kleitman monitored electrical activity in the brain during sleep using EEG recordings in order to wake ppts during different stages of sleep. Ppts who were awakened during REM sleep reported dreaming 90% of the time. Dreams were recalled in detail . Only 7% who woke up in NREM sleep reported dreams. Other studies have also shown that dreaming occurs outside of REM sleep and people in REM didn’t always report dreaming. But it provides a way of identifying when someone is dreaming and so might provide theorists with a way to explain dreaming.
ARTIFICIAL SETTING FOR LAB EXP WHERE DREAMING IS MEASURED WITH ELECTRODES MAY MEAN THE RESULTS LACK ECO VAL AS THEY ARENT REPRESENTATIVE OF TRUE SLEEPING ENVIRONMENTS AND SO THE QUALITY AND QUANTITY IF SLEEP MAY BE AFFECTED. Lack external validity to wider generalisation
Klein et al found ppts tested on verbal and spatial tasks had their performances linked to a 96 minute cycle similar to the ultradian rhythm in the sleep stages. This suggests a possible link to cognitive ability and the stages of sleep being potentially linked suggesting sleep may be an important element for efficient brain functioning.

Gerkema et al found that ultradian rhythms tended to correlate with brain and body size with large animals having longer sleep cycles. This suggests that the purpose of such a cycle could be linked to restoration theories of sleep and such a cycle exists for the recuperation of the body.

Question 4

IDA

Answer 4

Ultradian rhythms exist in everyone which suggests rhythms are part of our nature rather than nurture and endogenous pacemakers may govern them.