About the lecture

In this lecture, we think in more detail about circadian rhythms, focusing in particular on: (i) the fact that circadian rhythms are approximately 24 hours in length; (ii) the digestive system’s production of proteins based around expected mealtimes as an example of a circadian rhythm; (iii) the sleep-wake cycle as an example of a circadian rhythm, which varies between animal species and humans; (iv) light as the primary exogenous zeitgeber in the circadian sleep-wake cycle; (v) the detector of light being the eye, which signals the suprachiasmatic nucleus, which acts as the ‘body clock’ or endogenous pacemaker; (vi) the hormonal processes involved in maintaining a state of being awake, including the release of cortisol to regulate alertness; (vii) melatonin, produced by the penial gland, which induces sleep; (viii) exercise, work, travel and mealtimes, all of which can influence the circadian rhythm.

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).