No Evidence for a Targeted Memory Reactivation Effect on Word-Meaning Priming

The subordinate meaning of a homonym becomes temporarily more accessible after it is encountered, an effect termed word-meaning priming. Over the longer-term, word-meaning priming is better maintained across periods of sleep compared with wakefulness. This has been explained as sleep actively consolidating episodic memories related to recent linguistic events (Gaskell et al., 2019). Here, we tested this hypothesis by investigating whether word-meaning priming can be boosted following sleep using targeted memory reactivation (TMR), a technique of biassing specific memories for sleep-based consolidation by presenting information-associated sensory cues during sleep. Experiment 1 confirmed that word-meaning priming is elicited with the inclusion of encoding instructions that are necessary for a TMR manipulation. In Experiment 2, 40 (of 80) homonyms were primed toward their subordinate meaning in an exposure phase via a sentence, which was also associated with an auditory cue (the homonym) for TMR. Participants then took a ~2 hour nap, where half of the cues from exposure (memory cues) were replayed with the aim of strengthening the subordinate sentence meaning, along with 20 cues that had not been encountered previously (control cues). After sleep, there was an overall word-meaning priming effect, however there was no additional benefit of TMR on priming, nor did TMR benefit the recall of contextual information. Interestingly, there was an increased sleep spindle/beta band power response to memory cues relative to control cues, indicating cue-evoked memory reprocessing during sleep. These findings imply a bounded role of sleep in actively consolidating linguistic-related memories.