Associate ProfessorSveta Postnova

Project Opportunities

Title: The Physics of Circadian Desynchrony

Summary of opportunity:

This project will investigate brain mechanisms and health consequences of circadian misalignment.

Opportunity synopsis:

Every cell and every organ in our body has circadian (~24 hour) oscillators that control timing of all biological processes. The oscillators in the different organs and cells are coupled to each other and their phases are continuously adjusted by environmental time cues, such as light, meals and exercise. In healthy state these clocks and the environment are synchronized. Their desynchrony, in the short-term leads to disturbances of sleep, alertness, metabolic and immune functions, while in the long-term it is linked to disease development, including obesity, diabetes, mental disorders, and cancer. Modern lifestyles put pressure on our circadian oscillators with artificial lighting, daylight saving time, around the clock work hours, and transmeridian travel all causing different degrees of circadian desynchrony.

This set of projects will investigate mechanisms underpinning circadian desynchrony and aims to develop strategies for quick re-synchronization of the oscillators and the environment that can be deployed in the real-world. The approaches that will be used include neural mass modelling of brain dynamics, data analysis, and may include software development.

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Project Opportunities

Title: QUANTIFYING INTER-INDIVIDUAL VARIABILITY IN CIRCADIAN RHYTHMS

Summary of opportunity:

The overarching goal of this set of projects is to understand the brain mechanisms of inter-individual variability in circadian rhythms and develop tools for personalized prediction of sleep, alertness, and circadian rhythms in the real-world.

Opportunity synopsis:

Insufficient and disturbed sleep are widespread phenomena in modern society with nearly 7.4 million Australians affected daily. Sleep loss induces adverse changes in alertness resulting in accidents and loss of life, e.g., contributing to 20-30% of fatal car crashes each year. Impaired alertness is unavoidable in occupations with shiftwork like healthcare, police, and fire and rescue service. The degree of impairment, however, is highly variable across individuals with the most vulnerable being at highest risk of accidents. Identifying vulnerable vs. resilient individuals and predicting an individual’s alertness is critical to minimising accident risks and improving safety. To address this major problem, these projects will combine biophysical modelling and big data to uncover the key brain mechanisms of individual variability in alertness and its changes due to sleep deprivation. This combined biophysical modelling and big data approach will allow us to probe brain mechanisms of individual differences in alertness that are not assessable by each of the methods alone.

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Project Opportunities

Title: MODELLING EFFECTS OF LIGHT ON THE CIRCADIAN RHYTHMS

Summary of opportunity:

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.

Opportunity synopsis:

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.

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Project Opportunities

Title: Understanding brain circadian rhythms and their desynchrony

Summary of opportunity:

Projects in this area of research will investigate different aspects of brain mechanisms and health consequences of circadian misalignment.

Opportunity synopsis:

Every cell and every organ in our body has circadian (~24 hour) oscillators that control timing of all biological processes. The oscillators in the different organs and cells are coupled to each other and their phases are continuously adjusted by environmental time cues, such as light, meals and exercise. In healthy state these clocks and the environment are synchronized. Their desynchrony, in the short-term leads to disturbances of sleep, alertness, metabolic and immune functions, while in the long-term it is linked to disease development, including obesity, diabetes, mental disorders, and cancer. Modern lifestyles put pressure on our circadian oscillators with artificial lighting, daylight saving time, around the clock work hours, and transmeridian travel all causing different degrees of circadian desynchrony.

This set of projects broadly focuses on mechanisms underpinning circadian desynchrony, individual differences in circadian rhythms, and strategies for quick re-synchronization of the biological oscillators and the environment. The approaches that will be used biophysical modelling, nonlinear dynamical systems, machine learning, AI, and data analysis.

A domestic PhD scholarship funded by NHMRC Ideas grant is available for the project in this research area focusing on quantitative modelling of shiftwork (contact the supervisor for detail). 

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Project Opportunities

Title: Understanding brain circadian rhythms and their desynchrony

Summary of opportunity:

Projects in this area of research will investigate different aspects of brain mechanisms and health consequences of circadian misalignment.

Opportunity synopsis:

Every cell and every organ in our body has circadian (~24 hour) oscillators that control timing of all biological processes. The oscillators in the different organs and cells are coupled to each other and their phases are continuously adjusted by environmental time cues, such as light, meals and exercise. In healthy state these clocks and the environment are synchronized. Their desynchrony, in the short-term leads to disturbances of sleep, alertness, metabolic and immune functions, while in the long-term it is linked to disease development, including obesity, diabetes, mental disorders, and cancer. Modern lifestyles put pressure on our circadian oscillators with artificial lighting, daylight saving time, around the clock work hours, and transmeridian travel all causing different degrees of circadian desynchrony.

This set of projects broadly focuses on mechanisms underpinning circadian desynchrony, individual differences in circadian rhythms, and strategies for quick re-synchronization of the biological oscillators and the environment. The approaches that will be used biophysical modelling, nonlinear dynamical systems, machine learning, AI, and data analysis.

A domestic PhD scholarship funded by NHMRC Ideas grant is available for the project in this research area focusing on quantitative modelling of shiftwork (contact the supervisor for detail). 

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Project Opportunities

Title: Quantitative modelling of sleeping brain

Summary of opportunity:

Projects in this area of research will investigate different aspects of sleep-wake regulation by the brain, role of sleep in the daily brain clearance, and links between sleep and development neurodegenerative disorders.

Opportunity synopsis:

Why do we sleep and how does the brain transition into this seemingly unconscious state and out of it? How does sleep loss affect our alertness and memory, and why is long-term sleep loss associated with neurodegenerative disorders like Alzheimer’s disease? What do sleep and anaesthesia have in common? Projects in this research area will use quantitative modelling, machine learning, and sophisticated data analysis to address these questions. The recently discovered glymphatic system in the brain, for the first time allows us to build mechanistic models linking sleep, brain clearance and long-term effects of sleep disturbances on the brain health to test hypothesis, make predictions, and develop interventions. 

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Project Opportunities

Title: Individualized predictions of sleep, performance, and circadian rhythms

Summary of opportunity:

The overarching goal of this set of projects is to understand the brain mechanisms of inter-individual variability underpinning our differences in brain rhythms and response to disturbances like sleep deprivation.

Opportunity synopsis:

Insufficient and disturbed sleep are widespread phenomena in modern society with nearly 7.4 million Australians affected daily. Sleep loss induces adverse changes in alertness resulting in accidents and loss of life, e.g., contributing to 20-30% of fatal car crashes each year. Impaired alertness is unavoidable in occupations with shiftwork like healthcare, police, and fire and rescue service. The degree of impairment, however, is highly variable across individuals with the most vulnerable being at highest risk of accidents. Identifying vulnerable vs. resilient individuals and predicting an individual’s alertness is critical to minimising accident risks and improving safety. To address this major problem, these projects will combine biophysical modelling and big data to uncover the key brain mechanisms of individual variability in sleep, circadian rhythms and alertness in young and old individuals undergoing sleep deprivation. It is expected that models with individualised predictions will be applied in real-world to track and optimise sleep and alertness in population. 

----------Current Research Projects----------

_x000D_ Broadly, the group focuses in brain dynamics of circadian rhythms and sleep.

_x000D_ Circadian rhythms: Circadian oscillations are present in every physiological function and every living organism on the planet, including plants and insects. We study how these 24-hour rhythms in, e.g., the human sleep-wake cycles, hormone levels, and alertness, are generated and how they are affected by the environmental time cues such as the solar light-dark cycle. We have a particular interest in mechanisms and health consequences of circadian misalignment - desynchronisation of the circadian rhythms from each other and/or from the environment. By using physically-based modelling and data science we quantitatively study this complex biological system, develop predictive tools and design interventions to minimise circadian misalignment.

_x000D_ Sleep dynamics: Why do we sleep and how does the brain transition into this seemingly unconscious state and out of it? How does sleep loss affect our alertness and memory, and why is long-term sleep loss associated with neurodegenerative disorders like Alzheimer�s? What do sleep and anaesthesia have in common? To answer these and other questions we use neural field, neural mass, and neural network modelling and experimental data collected at different physiological levels � from single neurons to whole brain activity.