Modelling jet lag and light therapy optimisation for jet lag recovery
Year: 2023
Type: dissertation
Abstract: The suprachiasmatic nucleus (SCN) in the mammalian brain generates our circadian rhythms and synchronises our biological processes with daily light variations. However, rapid time zone travelling can desynchronise the SCN neurons and disrupt the circadian rhythms, causing jet lag symptoms. The mechanism of jet lag and the role of the two regions of the SCN, the core and shell, remain unclear and its study is crucial to find new jet lag treatments. Bright light exposure is an efficient jet lag therapy, but its impact on the SCN is not yet fully understood. To solve these issues, jet lag was modelled with the core-shell model of the SCN, based on the Kuramoto model. It was assumed that jet lag recovery is equivalent to the resynchronisation of the SCN to the exterior light cycle. It was found that the core region of the SCN recovers faster than the shell region. While analysing the space of states of the SCN oscillators, it was found a region of slow dynamic states. Once in this area, the system takes a long time to leave it. This region is, thus, responsible for a long adaptation after eastward travelling, particularly across 8 time zones, compared to westward travelling. Then, light therapy was also modelled, considering the 6/8h eastward/westward time shifts. It was shown that a sufficiently long duration or high intensity of light pulses can be more detrimental than beneficial for speeding up the recovery of the SCN. The findings suggest that light therapy with moderate duration or intensity decreases the recovery time after travelling east but not west. Two light treatment protocols (one-session and multisession) were also considered. Thus, the protocols with optimal light intensity, duration and number of sessions giving the lowest recovery time were obtained. It was concluded that light therapy is customisable, ensuring the individual can choose the light therapy parameters according to their needs. The results of this study align qualitatively and quantitatively with existing data for humans and mice. All in all, this work is a relevant contribution to jet lag research, paving the way for the widespread use of light therapy in modern healthcare.
Author: Aleixo, Beatriz Gomes da Silva
Language: English
Subfield: Endocrine and Autonomic Systems
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7058403293