How we form memories is a complicated system as many different things can disturb the process, from drug use to emotional state. But there's one thing that we now know is critically important for memory, and that is sleep.

We tend to equate sleep with rest, but in fact parts of the brain are more active during sleep than they are during wakefulness. In particular, a part of the brain called the hippocampus, which is a central hub for integrating learning and memory, becomes very active during certain phases of sleep. Human sleep is subdivided into non-REM (non-rapid eye movement) sleep, sometimes called slow wave sleep and REM (rapid eye movement) sleep, and these different phases are associated with different types (patterns) of hippocampal activity. The hippocampus is activated during wakefulness, so neurons in the hippocampus, for example, code information about new places that we visit and is then reactivated during subsequent sleep when those neurons that encoded new memories come to life again. So you replay your waking experience whilst you're offline during sleep and it's this process which is thought to support the strengthening of memories.

Sleep and Circadian Hub Steering Group:

• Prof Matt Jones (Hub Lead, Professor of Neuroscience, School of Physiology, Pharmacology and Neuroscience)
• Dr Michele Bellesi (Honorary Senior Research Associate, School of Physiology, Pharmacology and Neuroscience)
• Prof Liz Coulthard (Professor of Cognitive Neurology, Bristol Medical School: Translational Health Sciences)
• Ms Rosemary Greenwood (Honorary Senior Lecturer, Bristol Medical School: Population Health Sciences)
• Dr Jane Hicks (Consultant Psychiatrist, Bristol Mental Health)
• Dr Ryan McConville (Senior Lecturer in Data Science, Machine Learning and AI, School of Engineering Mathematics and Technology)
• Dr Claire Rice (Associate Professor in Neuroinflammation, Bristol Medical School: Translational Health Sciences)
• Dr Rebecca Richmond (Senior Research Fellow, Bristol Medical School: Population Health Sciences)
• Dr Harry Rolinski (Honorary Lecturer, Bristol Medical School: Translational Health Sciences)