Credit: Neuron, Ngo et al.
Read aloud Waves that follow a slow rhythm - that characterizes the brain activity of humans in deep sleep. During this phase, experiences and information of the day are memorized. German researchers have now found an amazing way to reinforce this mechanism: By playing sounds in sync with the rhythm of the slow brainwaves of sleeping subjects, they were able to amplify the vibrations and actually increase their memory. During sleep, nerve cell groups begin to synchronize - they show activity that follows a common beat. By detecting electrical currents by means of electroencephalography (EEG), these different rhythms can be visualized. Depending on the depth of sleep and the associated characteristic pattern, sleep can be divided into different stages. Deep sleep is characterized by a particularly slow wave pattern of brain activity. Many different studies have already shown interactions between sleep and memory. The deep sleep phase is particularly important in this context.

Only harmony shows effect

The researchers around Hong-Viet Ngo from the University of Tübingen conducted their investigations with 11 subjects in the sleep laboratory. They were connected to an EEG via electrodes to document the sleep process. Once the participants reached the deep sleep phase, they would hear a sound whenever the rhythm of their brain activity reached the maximum of the amplitude. As a control, the researchers repeated the sleep experiment with all subjects - but this time sounded in deep sleep, a recurring tone that was not in line with the brain rhythm. Prior to the two trial runs, the subjects completed word association games that they should remember the next day.

The evaluations of the experiments showed that the subjects heard the synchronous tone during deep sleep, the intensity of their brain waves increased, and the duration of the deep sleep phases also increased. In the asynchronous sounds, however, the researchers did not record this effect. This result was also reflected in the memory tests: After the night with the stimulating sounds, the subjects were better able to remember the word associations they had learned the night before. display

"The big advantage is the simplicity of the process, " says co-author Jan Born of the University of Tübingen. The tone stimulation could thus become a tool to improve the sleep rhythm and thus the quality of sleep. And even the opposite of sleep could benefit, the researchers say, because even waking processes are characterized by rhythmic brain activity. "It may also be possible to use the procedure to optimize attention phases, " says Born.

Hong-Viet Ngo (University of Tübingen) et al .: Neuron, doi: 10.1016 / j.neuron.2013.02.036 © science.de - Martin Vieweg

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