A lot goes on in a sleeping brain

Sleep: Science Café Wageningen will be considering the subject of sleep and the brain on Thursday. Somnologist Sebastiaan Overeem (Radboud University and Kempenhaeghe Sleep Centre) and sleep expert Ysbrand van der Werf (VU University Amsterdam and Dutch Institute for Neurosciences) will talk about the state of the art in their field. Van der Werf answers a few questions here in a sneak preview. When you say you are a sleep researcher you are probably never short of something to talk about? ‘That is right and it’s a nice thing about my subject. Everyone has an interest in sleep. Everyone sleeps badly sometimes. Sleep is very much part of people’s day-to-day experience.’ ## What is the question you are asked most often? ‘In the first place: why do we sleep? And then: is it really true that you need eight hours of sleep?’ ## And? ‘The answer to the why question is the holy grail of sleep research. It is still an unanswered question. Sleep is very extraordinary behaviour of course. Why do you have to spend so much of your day in a kind of coma? We know a few answers but they do not in themselves cover the whole story. The repair and growth function of sleep is important. The maintenance of the brain itself. But that is not all there is to it.’ ## I sleep eight hours a day. Is that bad? ‘People sleep on average 7 to 8 hours, but that is just an average. So large deviations both below and above that are normal. These differences have to do with the depth of the sleep. So it’s to do with the efficiency of the sleep.’ ## What is the biggest misunderstanding about sleep? ‘That nothing happens in your brain while you are sleeping. That it is a kind of quiet time. But the brain is just as active at night as it is by day. The total energy consumption is the same. There is very rich activity going on in the brain while you sleep. At the science café I will show some examples of brain scans.’ How bad is sleeplessness? ‘Sleeplessness is an epidemic. Ten percent of the population suffers from true insomnia. And then I am not talking yet about sleeping badly: 30 percent of the population suffers from this. ‘Sleeping badly’ in combination with tiredness is the most common complaint in the world. Sleep problems are a major personal, social and economic problem.’ ## Are dreams deceptive? ‘Yes, I would say so. Dreams are fantasies of the brain made up by the sleeper. Dreaming is a creative process and it does not reflect reality. So you should take dreams with a pinch of salt.’ (Science Café Wageningen, Thursday 27 September at Café Loburg)