About the lecture

In this lecture, we think about the three main types of biological rhythm, focusing in particular on: (i) infradian, circadian and ultradian rhythms; (ii) defining an endogenous pacemaker as an internal process or structure which regulates a biological rhythm; (iii) the suprachiasmatic nucleus, which is influential in maintaining the sleep-wake cycle; (iv) defining exogenous zeitgebers as external factors which impact internal processes, such as light; (v) the fact that infradian rhythms last longer than 24 hours, circadian rhythms last approximately 24 hours and ultradian rhythms last less than 24 hours; (vi) an example of an infradian rhythm being the female menstrual cycle, which is regulated by hormones and usually lasts approximately 23-36 days in humans; (vii) the sleep-wake cycle as an example of a circadian rhythm in humans; (viii) stages of the sleep-wake cycle, specifically looking at Rapid Eye Movement (REM) and non-REM sleep.

About the lecturer

Dr Liz Halstead is a lecturer in psychology in the Division of Psychology and Language Sciences at University College London. Dr Halstead’s research interests are in sleep psychology and cognitive therapy. Some of Dr Halstead’s recent publications include ‘Cross-country comparison of parental reports and objective measures of sleep patterns of typically developing children and autistic children between the UK and South Korea.’ (2023) and ‘Towards a Distinct Sleep and Behavioural Profile of Fetal Alcohol Spectrum Disorder (FASD): A Comparison between FASD, Autism and Typically Developing Children’ (2023).