PhD Studentship: Sleep, cognition and cerebrovascular functioning across the lifespan, PhD Studentship (Funded by the QUEX Institute)

Project Title: Sleep, cognition and cerebrovascular functioning across the lifespan, PhD Studentship (Funded by the QUEX Institute)

Sleep is an essential recuperative and restorative process. Just one night of sleep loss has been shown to impair a variety of cognitive abilities. These abilities are essential for learning, work, social participation, and independence throughout life. Habitual sleep loss is also a risk factor for cognitive decline and dementia.

The brain stores very little energy, which means that increases in cerebral metabolism during a cognitive task must be supported by region-specific brain blood flow. The ability to match increases in brain activation with blood flow (“neurovascular coupling”) is critical for cognitive health. This ability generally declines with age, and is thought to precede cognitive decline and dementia. Alterations in this fundamental process are also observed following sleep loss, and may contribute to the alterations in cognitive ability associated with poor sleep. However, few studies have experimentally addressed this.

There is also a tight coupling between cerebral metabolism and blood flow during sleep, and this is dynamic across sleep stages. For example, brain blood flow increases during rapid eye movement (REM) sleep. Reduced blood flow during REM sleep has been associated with poorer cognitive function and implicated in cognitive decline. Rhythmic neural activity and arterial pulsations in the brain during non-REM sleep are also thought to aid the clearance of ’waste’ compounds from the brain, but the effectiveness of this “pump” may be lost without close neurovascular coupling. Emerging data indicate that these processes are also altered due to sleep loss, and may provide a further mechanism that links poor sleep to poor daytime cognitive outcomes.

The aim of this PhD studentship is to address these research gaps in order to better understand the relationship between sleep, cognitive function and cerebrovascular function. To do so, will require symbiotic collaboration between research groups at Exeter and Queensland.

Adolescents, adults, and older adults will be recruited into a series of experimental trials, utilising existing links (e.g. local schools) and infrastructure (the Exeter 10,000). Sleep will be manipulated via established paradigms including partial or complete sleep restriction, and via manipulation of circadian timing of sleep and wake times. This will only be possible via expertise from Drs Smith and Mann (Queensland). We will observe the influence of these manipulations in sleep on a variety of age-appropriate cognitive outcomes in each age group. These may include measures of reaction time, cognitive throughput, decision making and risk, attention and concentration, and potentially other indices such as wake EEG, heart-rate variability, and pupillometry. We will also quantify any changes in the coupling between cerebral metabolism & brain blood flow across a variety of cognitive challenges by using the minimally obtrusive transcranial Doppler techniques which Dr Bond has extensively used in adolescents & adults (Exeter).

Finally, the adolescents recruited in Year 1 of the PhD will be invited back in Year 3, in order to understand whether the effects of sleep loss change across pubertal maturation, which is a contemporary concern amongst education policy makers.

The research project will involve working with under 18 year olds & therefore the applicant may need appropriate clearance through the Disclosure & Barring Service (DBS) check if working with adolescence with the UK and a National Police Check whilst working in Australia. Furth details & guidance would be provided to the successful candidate.

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