2024 - U4O1 - Circadian & Ultradian Rhythms

The article uses the term 'body clock'. Using appropriate psychological terminology, explain what the authors mean when they refer to the term 'body clock'. (2 marks).

Answer explanation

What would be an appropriate label for the vertical axis of Figure 1?

Answer explanation

Steph chose not to include adolescents under the age of 18 in her research because they might be experiencing a circadian phase disorder. Identify and describe the likely circadian phase disorder experienced by adolescents under the age of 18. (2 marks)

Answer explanation

Predict the effect that the circadian phase disorder identified in part b.i. would have on the results of Steph’s research if adolescents under the age of 18 were added to the sample. Justify your response.

Archer’s difficulty forming and consolidating memories during periods of insomnia was likely due to a lack of which type of sleep?

• rapid eye movement (REM) sleep.

• non-rapid eye movement (NREM) Stage 1 sleep.

• non-rapid eye movement (NREM) Stage 2 sleep.

• non-rapid eye movement (NREM) Stage 4 sleep.

Answer explanation

The figure below is a hypnogram representing the sleep cycle of a healthy adult. Outline two differences between rapid eye movement (REM) sleep and non-rapid eye movement (NREM) sleep evident in the hypnogram above. (2 marks)

Answer explanation

Compare how REM and NREM sleep would differ in a hypnogram of a healthy adolescent and a hypnogram of an elderly person. (2 marks)

Answer explanation

Comparing a person’s sleep-wake circadian rhythm to their ultradian rhythm of rapid eye movement (REM) and non-rapid eye movement (NREM) sleep, it can be said that

• both occur once in approximately a 24-hour period.

• both occur more than once in approximately a 24-hour period.

• ultradian rhythms occur approximately once in a 24-hour period but circadian rhythms occur more frequently.

• circadian rhythms occur approximately once in a 24-hour period but ultradian rhythms occur more frequently.

Answer explanation

A study was conducted where subjects were selectively prevented from entering REM sleep over a period of five days. On the sixth night, they were allowed to sleep normally. The most likely response in terms of the proportion of REM sleep on the sixth night would be

• a decreased proportion of REM sleep.

• an increased proportion of REM sleep.

• an increased proportion of stage 2 sleep.

• an increased proportion of stages 3 and 4 sleep.

Answer explanation

If Megan were attached to an electroencephalograph (EEG), which of the following changes to her brain waves would be likely to be observed when she woke up compared to just before waking?

• an increase in frequency and a decrease in amplitude

• a decrease in frequency and an increase in amplitude

• no change in amplitude

• no change in frequency