Learning New Vocabulary during Deep Sleep
Sleeping time is sometimes considered unproductive time. This raises the question whether the time spent asleep could be used more productively, e.g. for learning a new language? Up-to-now sleep research focused on the stabilization and strengthening of memories that had been formed during wakefulness. However, learning during sleep has rarely been examined. There is enough evidence for wake-learned information undergoing a revision by replay in the sleeping brain. The replay during sleep strengthens the still weak memory and leaves the newly acquired information in the pre-existing store of knowledge.
If re-play during sleep improves the storage of wake-learned information, then first-play, i.e. the initial processing of new information, should also be possible during sleep.
The research group of Katharina Henke examined whether a sleeping person is able to form new semantic（语义的）associations between played foreign words and translation words during the brain cells' active states, the so-called "Up-states." It turned out to be that what they thought was reasonable. When we reach deep sleep stages, our brain cells progressively coordinate their activity. During deep sleep, the brain cells are commonly active for a brief period of time before they jointly enter into a state of brief inactivity. The active state is called "Up-state" and the inactive state "Down-state". The two states alternate（交替）about every half-second.
New evidence for sleep-learning challenges current theories of sleep and theories of memory. The concept of sleep that we are separated from the physical environment is no longer reasonable. "It's false that complex learning be impossible during deep sleep," says Simon Ruch, co-first-author. "In how far and with what consequences deep sleep can be applied for the acquisition of new information will be a topic of research in upcoming years," says Katharina Henke.
The research group of Katharina Henke is part of the Interfaculty Research Cooperation (IRC). Thirteen research groups in medicine, biology and psychology are part of the IRC. The aim of these research groups is to gain a better understanding of the mechanisms（原理）involved in sleep and consciousness.
