Improving memory via automated targeted memory reactivation during sleep

Nathan W. Whitmore*, Jasmine C. Harris, Torin Kovach, Ken A. Paller

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


A widely accepted view in memory research is that previously acquired information can be reactivated during sleep, leading to persistent memory storage. Targeted memory reactivation (TMR) was developed as a technique whereby specific memories can be reactivated during sleep using a sensory stimulus linked to prior learning. As a research tool, TMR can improve memory, raising the possibility that it may be useful for cognitive enhancement and clinical therapy. A major challenge for the expanded use of TMR is that a skilled operator must manually control stimulation, which is impractical in many settings. To address this limitation, we developed the SleepStim system for automated TMR in the home. SleepStim includes a smartwatch to collect movement and heart-rate data, plus a smartphone to emit auditory cues. A machine-learning model identifies periods of deep sleep and triggers TMR sounds within these periods. We tested whether this system could replicate the spatial-memory benefit of in-laboratory TMR. Participants learned locations of objects on a grid, and then half of the object locations were reactivated during sleep over 3 nights. Recall was tested each morning. In an experiment with 61 participants, the TMR effect was not significant but varied systematically with stimulus intensity; low-intensity but not high-intensity stimuli produced memory benefits. In a second experiment with 24 participants, we limited stimulus intensity and found that TMR reliably improved spatial memory, consistent with effects observed in laboratory studies. We conclude that SleepStim can effectively accomplish automated TMR, and that avoiding sleep disruption is critical for TMR benefits.

Original languageEnglish (US)
Article numbere13731
JournalJournal of Sleep Research
Issue number6
StatePublished - Dec 2022


  • memory consolidation
  • memory replay
  • sleep
  • sleep disruption
  • wearable technology

ASJC Scopus subject areas

  • Cognitive Neuroscience
  • Behavioral Neuroscience


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