Biological mechanisms underlying the mood-regulating effects of light

Light has a well-documented positive effect on mood. Indeed, these mood-enhancing effects are sufficiently powerful that light is now recognised as an effective clinical tool for treating both seasonal and other forms of depression. Unfortunately, at present, the biological mechanisms underlying these mood-enhancing effects of light are very poorly understood. This presents a barrier towards developing more effective treatment strategies and for optimising day to day lighting (e.g. in the home, workplace etc.) so as to enhance our general well-being. The main origin of our current lack of knowledge has been the lack of an appropriate animal model with which to determine the organisation and properties of the retinal and brain circuits involved, since most lab studies to date have focused on the use of nocturnal rodents which are naturally wired to avoid light exposure.

This project now offers a fantastic opportunity to drive a step-change in our understanding of the biological mechanisms via which light influences mood. We have established a colony of day-active rodents (Rhadbomys) which have a human-like visual system and therefore present an ideal translational model to determine the neural basis of the mood-regulating effects of light. Working with the supervisory team, the successful applicant will receive expert training in a range of highly sought after in vivo and surgical techniques including the use of large scale in vivo electrophysiological recording, the latest genetic techniques for manipulating neuronal circuit function (opto-/chemogenetics), whole animal physiological monitoring (including telemetric recording of ECG/EEG, serial blood sampling, indirect calorimetry) and behavioural assays of mood (including forced swim, sucrose preference, elevated plus maze). The student will also gain extensive experience with sophisticated analytical approaches for the large datasets these scientific techniques provide (including the use of common science/engineering programming languages e.g. MATLAB, LabVIEW, python) and skills in optics/basic electronics, enabling them to construct bespoke experimental apparatus.

Through the course of the project, the applicant will thus determine: which brain regions are involved in the immediate mood-enhancing effects of light? How are signals from the various photoreceptors in the retina combined to produce these effects? How can we best adjust lighting to optimizing mood-promoting effects? What are the mechanisms by which altered light exposure causes depressive symptoms (including contributions of the circadian clock and sleep)?

Collectively, the project will thus provide key insights into the fundamental biological mechanism by which light influences mood in mammals which can potentially be exploited to improve human health and the welfare of managed animals. This goal aligns well with the BBSRC strategic priorities of animal health, healthy ageing across the life-course and systems approaches to the biosciences.