Albrecht Vorster: Bringing the science of sleep to the public

Albrecht Vorster is a PhD student at the Institute for Medical Psychology and Behavioural Neurobiology who decided to take a year off during his doctoral studies to write a popular science book Why do we sleep? (original: Warum wir schlafen, Heyne Verlag). Published by Random House in May of 2019, the book was recently issued for its second run. Albrecht kindly agreed to tell Neuromag the story behind the book, the struggles and the joys of writing and the reasons why we sleep.

Albrecht, how did you come up with the idea to write a book about sleep?

As a sleep researcher, I found myself looking for the simplest neurobiological mechanisms of sleep. During my master’s thesis, I was working with Drosophila – the fruit fly – yet with its 100 000 neurons, I still found it to be too complex. I knew that Aplysia (Aplysia californica, a sea slug found in the Pacific Ocean) was widely used in memory research, and as memory mechanisms are related to sleep, I started searching for sleep research in Aplysia. A PubMed search gave me 0 results! I then knew that I needed to find a lab where I could work with Aplysia. After quite some struggle to convince established researchers that Aplysia sleep research might provide a new outlook on sleep, I worked on this topic in Florida.

Upon my return to Germany, I read a popular science book called Darm mit Charme: Alles über ein unterschätztes Organ (Gut: The Inside Story of Our Body’s Most Underrated Organ) by German writer and science slammer Giulia Enders. I thought to myself: nothing like this exists on sleep. Such a book has to be written! On the German book market we either have books written by scientists for scientists in a language that 90% of the population would not understand, or we have books written by journalists who have no training in biology or neuroscience, thus their texts are often full of ambiguous information. This was six years ago. I had some time on my hands, so I sat down and wrote a list of chapters and an introduction. Some of those words even ended up in the book!

I was lucky enough to meet Prof. Dr. Jan Born, a sleep and memory researcher working in Tübingen, while I was still in the US. We agreed that I would come to Tübingen for my PhD. During the studies I was in need of biology student assistants, so I started doing science slams on sleeping slugs, hoping this would help me recruit some help. That didn’t happen but the slam became very popular. At the same time, I was also teaching a course on sleep medicine, which I based on my work-in-progress book chapter list. With some brilliant student questions that I had no answers for, I was gathering a good amount of content that I could later use for the book.

In 2017, I received an email from a publishing agency, saying that they loved my science slam and that they wanted me to write a book on sleep. At first, I thought this was a scam, so I looked them up. They turned out to be a very honorable agency, so I provided them with an exposé – a chapter list and the first two chapters – so that they could pitch the book to different publishing houses. Keep in mind that the text that we had at this point only made up 5% of the book. We got eight offers from different publishers to do the book. This was beyond what anybody could have hoped for. I already knew from my initial attempts in writing that this was no evening after-work activity. So, I took a year off from my studies to write the book.

What was it like to take a break from your studies and just work on the book?

It was very cool to focus on one thing. And I learned so much! Every week I would dedicate two to three days to reading the existing research. In my PhD work, I did not usually have enough time to go into it in such depth. On the other hand, writing is very lonely. There is no romanticism about writing in a cozy cafe when inspiration strikes. No, you need a very strong structure even when you are writing for the public.

Just like writing a paper.

Image credits: Sebastian Blutau

You first read some papers, then you formulate an idea of what you want to write. And then you write.Writing for the public is also a little different. They are not scientists, so they do not need to read your writing if they don’t like it. You have to capture their interest. All the complicated biology terminology had to be “back-translated” as well. I never used the word “neuron” to not lose the interest of those people who do not know what a neuron is. Everybody, though, knows what a nerve cell is, so that’s the term I used. I have tried to be very basic in language but still very strong in science, to keep the book about the real science. In the end, the book was only 10% inspiration and 90% of just sitting down and working.

Do you know how the book was received by the audience?

This is a hard question to answer because only a small proportion of the people who read it actually interact with you. But I haven’t received any strong criticism yet. From what I’ve heard, people like it. Just a few days ago a student from the University of Jena wrote to tell me that the book has changed her life and made her think of doing another PhD on sleep! This is both very flattering but also important because there is still a lack of sleep researchers. Just imagine, here in Germany we only have one full professorship in sleep medicine. One!

The topic of sleep is also not taught enough to medical students. Every neurological disease comes with a change in sleep: depression, Parkinson’s, Alzheimer’s, just to name a few. For example, 50% of Parkinson’s patients have REM sleep behaviour disorder 15 years before the onset of the typical symptoms. We also know that 95% of people who show signs of REM sleep behaviour disorder will develop Parkinson’s or another neurodegenerative disease within the next 15 years. It is the strongest sign of the impending disease, and it can be identified a lot sooner than any other early onset symptoms. And we can prevent these diseases by treating REM sleep behaviour disorder with melatonin therapy. But nobody is talking about it! We need to change people’s perception of sleep and make them understand how important it is.

So, why do we sleep?

Sleep is like going to the barber: first washing, then cutting and then shaping your hair. During the night, the interstitial space between neurons increases by about 60% and water, taken from the arteries, flushes this interstitial space, clearing it from harmful proteins. This glymphatic system has only recently been discovered by Danish neuroscientist Dr. Maiken Nedergaard. This is washing.

The cutting happens because during the day, as the brain learns, there is a net increase in connections between neurons. A continuous increase in connectivity poses three problems: First, you need more space, but space is limited. Second, you need more energy, but the brain already consumes 25% of the energy of the body. And third, the signal-to-noise ratio deteriorates. So, cutting down on dendritic connections, like pruning the branches of trees, not only helps to avoid these problems but also allows us to learn new things the next day.

The final function is shaping: during the night, a cross-talk between the hippocampus and the cortex happens, replaying the memories of the day. By connecting and comparing new memories with memories from the past – what we call gist extraction – you build general knowledge, like “Tübingen is a university town”.

Two additional functions of sleep are important to mention. One is for your metabolism – if you do not sleep, you become a bit diabetic. Without sleep your insulin and blood sugar levels become misaligned, making you more likely to become obese or insulin resistant. Another important function is for your immune system – during sleep, immune cells meet at the lymph nodes and talk to each other. This way your immune system is better prepared for the challenges of the next day. This is why it is important to sleep after you get a vaccination.

To sum up, sleep is by the brain, for the brain and of the brain. We fall asleep because our brain forces us. Brain health depends on sleep. And if we do not understand sleep, we do not understand half of the process of learning and memory formation.

Aiste Ambrasé is currently a GTC doctoral student and member of the work group ‘innovative Neuroimaging in Psychiatry’ led by Prof. Birgit Derntl in Tübingen.

Johanna Salu is currently a research assistant in the Neural Information Processing lab of Prof. Dr. Felix Wichmann.


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