April 12, 2013
Sound Stimulation Shown To Enhance Memory
April Flowers for redOrbit.com - Your Universe Online
A new study reveals that the slow oscillations in brain activity that occur during slow-wave sleep are critical for retaining memories. Playing sounds synchronized to the rhythm of the slow brain oscillations of sleeping people enhances the oscillations, the researchers found, and boosts memory retention.
"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–and therefore portrays a straightforward tool for clinical settings to enhance sleep rhythms," says Dr. Jan Born, of the University of TÃ¼bingen.
The research team exposed 11 individuals to sound stimulations or to sham stimulations on different nights. The participants were better able to remember word associations they had learned the evening before when they were exposed to stimulating sounds in sync with the brain's slow oscillation rhythm. The researchers found that stimulation out of phase with the brain's rhythm was ineffective.
"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," explains Dr. Born.
This approach will be used more generally to improve sleep, the researchers believe.
"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," says Dr. Born.