The role of sleep in processing our waking life and making sense of difficult emotions and experiences has been little understood and disputed amongst scientists for many years.
But in a new book Dr Penny Lewis, a neuroscientist at The University of Manchester, explores the very latest research into the night-time brain to understand the real benefits of sleep, and why the old adage to 'sleep on a problem' could have real scientific evidence behind it.
Dr Lewis, who runs the Sleep and Memory Lab in the University's School of Psychological Sciences, explores how, while our body rests, the brain practices tasks it learned during the day, replays traumatic events to mollify them, and forges connections between distant concepts. She believes that by understanding the roles that the nocturnal brain plays in our waking life, we can improve the relationship between the two, and even boost creativity and become smarter.
Her new book The Secret World of Sleep: The Surprising Science of the Mind at Rest, Dr Lewis answers questions such as what is the evolutionary purpose of sleep and how are memories created during sleep and can we use this to aid learning? She also looks at why we dream and why it is important, how depression and PTSD affect sleep and why we need less sleep as we get older.
Far from switching off during the night, the brain moves through a complex and highly structured pattern of activities while you slumber. Dr Lewis's work offers an in-depth look at the sleeping brain, and explains why lack of sleep leads to dulled senses, impaired decision making, low moods, poor memory and even an altered moral compass. The book also offers a guide to good practice for sleeping and how to help yourself sleep better.
Dr Lewis has written for a number of popular science publications including New Scientist. Her research has been featured on the BBC as well as receiving funding from Wellcome Trust and Unilever.