Improvements in the Recognition of Sounds after Presentation during Sleep

The effect of targeted memory reactivation during sleep on auditory recognition remains unstudied. We report here our verification that the recognition of sounds which are difficult to discriminate can be improved by repeat presentation during daytime sleep following training. After two sequential sessions of recognizing one of two deviant sounds in the oddball paradigm, subjects of the study group were presented with one of the recognized deviants in sleep stage 3 (slow-wave sleep, SWS). The control group was presented with a novel deviant during sleep, which had not been presented for recognition. After sleep, the study group showed significant improvement in the recognition of sounds presented during SWS, which was accompanied by an increase in the amplitude and a decrease in the latency of the mismatch negativity (MMN) component of the event-related potential. The control group showed no significant differences in discriminating sounds or in MMN parameters after sleep. Our data provide evidence that targeted reactivation of sound memory during sleep promotes the neuroplastic rearrangements underlying learning sound recognition.