When the more than 80 billion neurons in our brain are communicating with one another, they transmit their signals in unison or in a precisely defined time sequence – just like a tune that has a particular rhythm. The rhythm in our brain varies according to the basic state in which we find ourselves: when we are awake, only quick sequences of alpha and beta waves are observed, while the slower theta and delta waves are typical during sleep.
"People who find it hard to fall asleep have problems making the transition into the slower activity phase", reports Professor Michael Nitsche from the Leibniz Research Centre for Working Environment and Human Factors (IfADo) in Dortmund. On the other hand, the frequency of the electric currents in the brain decreases unintentionally in people who suffer from drowsiness, for example as the result of a brain injury. Michael Nitsche and his team want to understand how the brain rhythms correlate with different sleep and consciousness states. To this end, they conducted an initial study in which they analysed the activity patterns in the brains of healthy test subjects using electroencephalography (EEG) in the sleep lab. A second study of 60 test subjects will then look more closely at communication between the neurons.
Magnetic stimulation to slow the brain’s activity
Studies like the one conducted by the Dortmund neuroscientist are the basis for helping people with psychosomatic sleep disorders in future – namely through targeted stimulation of the brain’s activity. "It is estimated that ten percent of the population in Germany are affected by such sleep disorders", says Nitsche. "For many years they have problems falling asleep, which makes them less able to perform well during the day. In their case, however, there is no purely organic underlying cause such as sleep apnoea or narcolepsy."
In future, it is hoped that they can be helped by techniques that have already been used to treat depression for some years now: techniques such as transcranial magnetic stimulation (TMS), which involve using powerful magnetic fields to externally influence the electrical currents in the brain. "We want to develop programmes with which to slow down the brain’s activity by means of TMS or transcranial direct-current stimulation", explains Nitsche. Short-term effects can already be induced using this method, says the Dortmund-based researcher. Longer term effects that might permanently help people with sleep disorders to fall asleep have not been achieved as yet, however.
How does a lack of sleep affect our work?
The study carried out at the sleep lab in Dortmund forms part of the EU-funded Luminous project involving neuroscientific research of consciousness. While sleep is studied in Dortmund, neurologists, psychologists and engineers from Barcelona, Liège, Milan, Rennes, Oxford and Tübingen are exploring other questions, such as the state of consciousness of coma patients.
Besides basic research, scientists at the IfADo in Dortmund also look at more application-oriented questions – such as how sleep deficit affects cognitive performance at the workplace. This is an important issue given that shift work is one of the risk factors for sleep disorders, and that it has increased hugely since the 1990s. The topic of the German Science Year 2018, initiated by the Federal Ministry of Education and Research, is "Work Worlds of the Future" (only in German). One question that is being investigated, for instance, is how work in today’s digital era affects people’s sense of wellbeing and health, and how work can be designed in future.
Leibniz Research Centre for Working Environment and Human Factors (IfADo)
The more than 200 employees at the Leibniz Research Centre for Working Environment and Human Factors at TU Dortmund University explore for example how stress influences our work performance and health. The IfADo offers young researchers a graduate programme as well as special programmes for female doctoral students.www.ifado.de