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Research / Sleep
Sleep deprivation (SD) is pervasive in modern societies and leads to decline in cognitive performance, depressed mood and poorer health. Poor sleep imposes a 2-4% drag on the GDP of developed nations.
At the CNL, we work on:
Characterizing the neurobehavioral changes associated with total or partial sleep deprivation and across the lifespan and their underlying mechanisms
This has been our signature contribution to cognitive neuroscience.
We have one of the world’s largest corpus of experiments characterizing the effects of a single night of total sleep deprivation on behaviour in young adults. Over the last 14 years, we have evaluated working memory, visual short term memory, selective attention, preparatory visual attention, peripheral processing capacity, speed of visual processing, distractor suppression, motor inhibition, risky decision making, valuation of monetary and non-monetary rewards, delay discounting, effort discounting, cognitive throughput, time-on-task effects, processing of emotional stimuli, the foreperiod and sequential effects and responses to stressful situations and cyber-bullying. Most of these experiments have been conducted using task-based fMRI.
Within some of those experiments we have documented inter-individual differences in vulnerability to sleep deprivation and their imaging correlates. We have shown how eyelid closures correspond to microsleeps and how ‘closing out the world’ extends to the auditory domain. During this period, there is an interesting set of co-activations occurring in the brain which has no counterpart during rested wakefulness.
We have mapped out how different behavioural and physiological measures in the well-rested state can be used to predict vulnerability vigilance decline following sleep deprivation.
In adolescents, we evaluated the effects of multiple nights of sleep restriction to 5H TIB on vigilance, processing speed, working memory and mood. We tracked the evolution of behavioural and EEG changes over the period of sleep restriction and two nights of recovery sleep. We determined how a second cycle of sleep restriction would impact behaviour and sleep and how an hour’s nap can alleviate vigilance decline. We have determined how learning and memory are impacted over the simulated school week.
Our work on older adults is featured in the other tab describing our research on healthy cognitive ageing.
Investigating how sleep benefits memory and learning
The role sleep plays in consolidating declarative and procedural memories has been investigated in many other labs and we are new entrants into this area.
To date, we have evaluated the effects of a nap and repeated practice following a night of sleep deprivation on procedural learning.
We have demonstrated the benefit of a nap on learning of a complex schema of facts.
We will be evaluating the benefit of nocturnal sleep and / or naps on very long term memory outcomes.
Improving adolescent sleep
This represents a novel effort to blend translational research and community service.
We have embarked on a multipronged strategy to improve adolescent sleep involving targeted multi-stakeholder education, time use management, napping and starting school later.
We are working with the Ministries of Education and Health to advocate for improving sleep in young persons.
Non-invasive measures to improve sleep duration and/ or quality
We have developed a method for phase locked loop acoustic stimulation to enhance slow oscillations in sleep and have shown how this can boost declarative memory consolidation during a nap in young adults (Ong et al., 2016)