This project aims to advance our understanding of the effects of light on the circadian rhythms and develop a detailed biophysical model of the circadian photoreceptor system that is responsible for the non-visual effects of light on human physiology.


Dr Svetlana Postnova

Research Location

School of Physics

Program Type



Circadian, 24-hour, oscillations are seen in nearly all biological processes and functions: from immunity and metabolism to sleep and alertness. These oscillations are generated by the circadian clocks that are present in every cell in human body and are all synchronised to work in harmony by the master circadian clock in the brain. Solar light-dark cycle is the key time cue that entrains the brain’s circadian oscillator to the period of exactly 24 hours. Effects of light on the circadian rhythms depend on the timing, intensity, history, and wavelength of light. This project specifically focuses on the effects of light wavelength on circadian rhythms. These effects are mediated by the interplay of the photoreceptors in the eye. The key player in circadian effects of light is melanopsin that is most sensitive to short wavelength of visible light (peak at 490 nm), but the rods and cones are involved as well in time- and irradiance-dependent way. The exact structure of the photoreceptor system responsible for the circadian effects of light is yet to be fully understood.

This project will use biophysical modelling to bring together different experimental findings in a unified theory explaining the complex biological system of interacting photoreceptors in the eye and its action on the circadian oscillators.

Additional Information

Candidates will require quantitative background, e.g., physics, mathematics, engineering, computer science and interest in biological systems.

HDR Inherent Requirements

In addition to the academic requirements set out in the Science Postgraduate Handbook, you may be required to satisfy a number of inherent requirements to complete this degree. Example of inherent requirement may include:

  • Confidential disclosure and registration of a disability that may hinder your performance in your degree;
  • Confidential disclosure of a pre-existing or current medical condition that may hinder your performance in your degree (e.g. heart disease, pace-maker, significant immune suppression, diabetes, vertigo, etc.);
  • Ability to perform independently and/or with minimal supervision;
  • Ability to undertake certain physical tasks (e.g. heavy lifting);
  • Ability to undertake observatory, sensory and communication tasks;
  • Ability to spend time at remote sites (e.g. One Tree Island, Narrabri and Camden);
  • Ability to work in confined spaces or at heights;
  • Ability to operate heavy machinery (e.g. farming equipment);
  • Hold or acquire an Australian driver’s licence;
  • Hold a current scuba diving license;
  • Hold a current Working with Children Check;
  • Meet initial and ongoing immunisation requirements (e.g. Q-Fever, Vaccinia virus, Hepatitis, etc.)

You must consult with your nominated supervisor regarding any identified inherent requirements before completing your application.

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Chronophysics, neurophysics, mathematical modelling, Eye, photoreceptors, brain dynamics, dynamical systems, complex systems, circadian photobiology, LIGHT, spectrum, wavelength.

Opportunity ID

The opportunity ID for this research opportunity is: 2865

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