People who listened to sounds that were synchronized to their slow brain wave oscillations while they were asleep experienced a boost in memory, Psych Central reported.
Experts said that these findings, published in the journal Neuron, suggest an easy, noninvasive way to influence human brain activity – as well as improve both sleep and memory.
“The beauty lies in the simplicity to apply auditory stimulation at low intensities — an approach that is both practical and ethical, if compared for example with electrical stimulation,” co-author Dr. Jan Born, of the University of Tübingen, in Germany, said.
Researchers exposed 11 people to sound simulations, or sham simulations, on different nights. When the study participants listened to stimulating sounds that were in sync with the brain’s slow oscillation rhythm, they were better able to remember word associations that they had learned the night before.
Notably, stimulation out of sync with the brain’s slow oscillation rhythm was ineffective, Psych Central reported.
“Importantly, the sound stimulation is effective only when the sounds occur in synchrony with the ongoing slow oscillation rhythm during deep sleep. We presented the acoustic stimuli whenever a slow oscillation ‘up state’ was upcoming, and in this way we were able to strengthen the slow oscillation, showing higher amplitude and occurring for longer periods,” explained Born.
Researchers believe that this approach might also be used more generally to improve sleep.
“Moreover, it might be even used to enhance other brain rhythms with obvious functional significance — like rhythms that occur during wakefulness and are involved in the regulation of attention,” Born said.