We can cultivate foreign language vocabulary in deep sleep; Vocabulary learned during sleep can be subconsciously recorded by the brain when we wake up.
The brain structures that control memory formation during sleep are the same brain structures that help us remember when we’re awake.
Sometimes sleep time is still seen as unproductive time.
A question arises: So how can sleep time become more productive? – for example, how does it help when learning a new foreign language?
Until now, research has generally focused on the stability and reinforcement of memories formed while people are awake, while learning during sleep has rarely been examined.
Much evidence has been presented that the information gathered during awakening is replayed and reconstructed during sleep.
Left: Scientists perform a sleep study using an electroencephalogram (EEG) that records electrical brain activity. Right: During deep sleep, slow oscillating high amplitude waves appear on the EEG. These waves are produced when brain cells rhythmically alternate the active phase (red: up state) and passive phase (blue: down state).
The process of replaying memories helps to consolidate still fragile memory imprints and to incorporate newly acquired information into the knowledge base. If replaying during sleep can improve memory, then the initial information processing stage can also be done during sleep, memory lasting long after awakening.
This is also the research question of Katharina Henke, Marc Züst und Simon Ruch of the Institute of Psychology and Interdisciplinary Research Collaboration “Sleep Decoding” at the University of Bern, Switzerland.
Researchers have shown for the first time that new words and their meanings can be connected during a nap and stored in the brain after awakening.
After waking up, the participants were able to reactivate the memories formed during sleep to find the meaning of the word when encountering the new word.
The hippocampus – an essential part of the brain during awake learning – also contributes to information seeking that forms during sleep.
The results of this experiment are published in the scientific journal Current Biology.
Katharina Henke’s research team tested whether a sleeping person could form new semantic associations between new words and translated words while brain cells were active – a process called ‘activity’. ‘.
As we fall into a deep sleep, our brain cells usually gradually adjust their activity.
During deep sleep, brain cells are normally active for a short time before entering a state of temporary inactivity.
The active state is called the “up state” , and the inactive state is called the ” down state”.
These two states alternate every 0.5 seconds. The semantic association between a ‘false word’ and its German meaning is only recorded and stored in sleep if the word pair is repeated many times in the active state (2,3, or 4 times). ).
For example, when a sleeping person hears the words ‘tofer=key’ and ‘guga=elephant’, after waking up they can identify the words “Tofer” and “Guga” representing objects larger or smaller.
“Interestingly, the linguistic areas of the brain and the hippocampus – the memory storage center in the brain – were activated during the retrieval of learned words,” said Marc Züst, co-author of the study. during sleep, because these brain structures normally only govern vocabulary learning while awake. deep sleep, awake when awake”.
In addition, new evidence demonstrating this sleep learning challenges all current sleep and memory theories.
Sleep is no longer an encapsulated mental state that separates us from our physical environment.
“We were able to show that even in deep sleep, people can still learn,” says Simon Ruch.
The present results echo a new theoretical concept of the relationship between memory and consciousness published by Katharina Henke in 2010 (Nature Research Neuroscience Review). “In the coming years, the research topic will be how to optimize deep sleep to gather new information and its implications,” Katharina said.
Katharina Henke’s research team is part of the Interdisciplinary Research Collaboration “Decoding Sleep: From Neuroscience to Health & Mind” (IRC).
Decoding Sleep is a large interdisciplinary research project funded by the University of Bern, Switzerland.
In the IRC there are also 13 research groups in medicine, biology, psychology and informatics. These research groups aim to explore the mechanisms involved in sleep, consciousness, and cognition.
The scientific research report was carried out in collaboration with Roland Wiest from the Center for Advanced Neurological Support (SCAN) at the Institute of Neurological Diagnostics and Interventions at Inselspital, University of Bern.
Both research groups are part of the BENSCO consortium, which consists of 22 interdisciplinary research groups specializing in hypnotics, epilepsy and the study of alternating states of consciousness.