
人工語彙の学習難易度によって、睡眠時の標的記憶再活性化の有効性と、その基盤となる神経活動が異なることが示された。


coremsg

Sleep associated memory consolidation and reactivation play an important role in language acquisition and learning of new words. However, it is unclear to what extent properties of word learning difficulty impact sleep associated memory reactivation. To address this gap, we investigated in twenty-two young healthy adults the effectiveness of auditory targeted memory reactivation (TMR) during non-rapid eye movement sleep of artificial words with easy and difficult to learn phonotactical properties. Here, we found that TMR of the easy words improved their overnight memory performance, whereas TMR of the difficult words had no effect. By comparing EEG activities after TMR presentations, we found an increase in slow wave density independent of word difficulty, whereas the spindle-band power nested during the slow wave up-states - as an assumed underlying activity of memory reactivation - was significantly higher in the easy/effective compared to the difficult/ineffective condition. Our findings indicate that word learning difficulty by phonotactics impacts the effectiveness of TMR and further emphasize the critical role of prior encoding depth in sleep associated memory reactivation.

### Competing Interest Statement

The authors have declared no competing interest.

Difficulty in artificial word learning impacts targeted memory reactivation and its underlying neural signatures

人工語彙学習の難易度が標的記憶再活性化とその基盤となる神経活動に及ぼす影響