With the time change, the “inner clock” gets out of step for some people – at least temporarily. But enough sleep is not only very important for health, but also for learning processes.
Learning right into the dolls before a difficult exam?
That might be exactly the wrong strategy. Because sufficient and good sleep is important to consolidate what you have learned, that much is certain.
But how this happens in detail, whether dream sleep or deep sleep is the decisive factor, is still a mystery even for experts. Because the brain is much less illuminated at night than it is during the day.
“But it works at night at least as complicated, probably even more complicated,” says Dieter Kunz (over at this website), head physician of the Clinic for Sleep Medicine at St. Hedwig Hospital in Berlin .
In humans, deep sleep and dream sleep alternate every 90 minutes or so – with the deep sleep phases being longer at the beginning of the night and the dream sleep phases towards morning.
Kunz and his team will soon publish a study in the journal “Sleep”, which will highlight the importance of dream or REM sleep, at least for procedural learning, i.e. learning automated processes such as cycling or walking.
REM stands for Rapid-Eye-Movement and describes the rapid eye movement under a closed eyelid in dreams. “The test persons were given an antidepressant that suppresses REM sleep,” explains Kunz.
Test subjects with REM sleep better
After sleep, they had to press a button at lightning speed in visual tests at certain optical signals. The test subjects in the placebo group, i.e. those who had REM sleep, performed significantly better.
For explicit learning, for example for vocabulary or historical data, it is probably the combination of the different sleep components that permanently stores the facts.
But learning means much more than that: “The memory that is formed during sleep is not a passive process where, so to speak, glue simply comes over the contents to fix them.
It is an active process, a process of abstraction away from the individual episode experienced and towards semantic memory,” says Leibniz Prize winner and sleep researcher Prof. Jan Born from the University of Tübingen.
For his latest studies, he and his team specifically focused on deep sleep. They initially also had their adult and child test subjects play a “button-down game” in which a button had to be pressed quickly when – apparently arbitrary – light signals appeared.
In fact, the light signals were switched in a complex pattern, but no participant consciously noticed this. After sleep, you can go for second test run was performed – and everyone performed significantly better.
Deep sleep phase important for learning processes
The increase was particularly noticeable in children, who by nature have more deep sleep phases. “Probably a reprocessing of stimulation occurs during sleep.
The children had extracted the hidden patterns particularly well. 13 of the 15 children knew the entire sequence by heart,” reports Born. “And it is the deep sleep phase in which this happens.”
In a further attempt Born therefore set about improving the deep sleep phases.
With quiet sound impulses, which were switched synchronously to the slow delta wave rhythm of the deep sleeper’s brain, it was possible to further slow down the frequencies, to increase the deflections. “The deep sleep becomes deeper, the memory performance increases,” concludes Born.
In older people, the deep sleep phases gradually decrease. Could a better deep sleep help them to regain more memory? “You can improve deep sleep in older people, but the effects are only moderate,” says Born. “The old brain just doesn’t produce so many slow waves any more.”
At least seven hours of sleep in a dark environment and aligned with the inner clock is therefore the primary advice to all those who want to learn something overnight.