Sleep, brain and behaviour laboratory
Sleep is traditionally defined and characterised by behavioural and electrophysiological criteria. For example, during sleep we are immobile and less responsive to the environment, and global cortical activity is distinctly different from an awake state. The differences between waking and sleep become less apparent as we look closer at the spatio-temporal patterns of cortical activity by recording local field potentials or neuronal spiking. It has been shown, that sleep-like patterns of neuronal activity are not uncommon during waking, even during active behaviours, and especially when the animals are drowsy or sleep-deprived. On the other hand, the main network oscillations during sleep – slow waves (~0.5-4 Hz) and spindles (~9-16 Hz) – are remarkably dynamic and idiosyncratic events, mostly occurring locally, and never encompassing the entire cortex at once. Slow waves are considered a reliable marker of preceding sleep-wake history, and a measure of sleep ‘intensity’. The ‘homeostatic principle’ postulates that the longer we stay awake, the more intense is our subsequent sleep. Recent evidence suggests that sleep homeostasis is a local process, and it has been identified both in cortical and subcortical structures, such as the dorsal striatum. Sleep spindles, which arise within the thalamocortical circuitry, also occur locally in the neocortex; and their occurrence varies greatly depending on the cortical region, the time of day and the immediate preceding state. Finally, individual cortical neurons are highly diverse with respect to the state dependency of their spiking activity, and, importantly, their response to preceding sleep-wake history. Over the last few decades our knowledge about sleep has progressed tremendously. However, the fundamental questions remain: what is ‘noise’ and what is ‘signal’ in cortical activity during sleep, and how does the global and precisely regulated state of sleep emerge from the activity (or lack thereof) of local and distributed, cortical and subcortical circuits.
In our research we use a broad range of techniques and approaches, such as behavioural tasks, electrophysiology, transgenic mouse models, local brain microstimulation and pharmacology.
Associate Professor Vladyslav Vyazovskiy is a member of Oxford University's Sleep and Circadian Neuroscience Institute.
Video credit: Vicky Isley and Paul Smith (boredomresearch)
Video credit: University of Oxford Podcasts
Hear more from Prof Vyazovskiy on the Sleep Science Podcast Episode 4: Local sleep, circadian rhythms and torpor.
Nuffield Department of Clinical Neurosciences
Department of Experimental Psychology
Department of Pharmacology
Department of Engineering Science
Radcliffe Department of Medicine
24 August 2021
New article on The Conversation website written by Dr Lukas Krone, Associate Professor Vladyslav Vyazovskiy and Professor Zoltán Molnár.
6 August 2021
DPAG DPhil students Gosia Cyranka and Sian Wilcox have been awarded prestigious Early Career Researcher Prizes at Physiology 2021, The Physiological Society's Annual Conference celebrating first-class physiology.
Dim light in the evening causes coordinated realignment of circadian rhythms, sleep, and short-term memory.
Tam SKE. et al, (2021), Proc Natl Acad Sci U S A, 118
The continued need for animals to advance brain research
Homberg JR. et al, (2021), Neuron, 109, 2374 - 2379
Waking experience modulates sleep need in mice.
Milinski L. et al, (2021), BMC Biol, 19
Diazepam effects on local cortical neural activity during sleep in mice.
McKillop LE. et al, (2021), Biochem Pharmacol