TMR provides the greatest benefit to memories recalled with a low degree of accuracy prior to sleep. The memory benefits of TMR may also be contingent on direct cue-memory associations.

Study ObjectivesMemories are strengthened during sleep. The benefits of sleep for memory can be enhanced by re-exposing the sleeping brain to auditory cues; a technique known as targeted memory reactivation (TMR). Prior studies have not assessed the nature of the retrieval mechanisms underpinning TMR: the matching process between auditory stimuli encountered during sleep and previously encoded memories. We carried out two experiments to address this issue.MethodsIn Experiment 1, participants associated words with verbal and nonverbal auditory stimuli before an overnight interval in which subsets of these stimuli were replayed in slow-wave sleep. We repeated this paradigm in Experiment 2 with the single difference that the gender of the verbal auditory stimuli was switched between learning and sleep.ResultsIn Experiment 1, forgetting of cued (vs. noncued) associations was reduced by TMR with verbal and nonverbal cues to similar extents. In Experiment 2, TMR with identical nonverbal cues reduced forgetting of cued (vs. noncued) associations, replicating Experiment 1. However, TMR with nonidentical verbal cues reduced forgetting of both cued and noncued associations.ConclusionsThese experiments suggest that the memory effects of TMR are influenced by the acoustic overlap between stimuli delivered at training and sleep. Our findings hint at the existence of two processing routes for memory retrieval during sleep. Whereas TMR with acoustically identical cues may reactivate individual associations via simple episodic matching, TMR with nonidentical verbal cues may utilize linguistic decoding mechanisms, resulting in widespread reactivation across a broad category of memories.

Previous research has suggested that integration of novel words into lexical competition benefits from a consolidation delay containing a period of sleep (Dumay & Gaskell, 2007). However, a recent study argued that learning novel words via a relatively implicit Hebb repetition task leads to later lexical integration independently of sleep (Szmalec, Page, & Duyck, 2012). It is not clear whether this different time course of lexical integration is a consequence of the learning method chosen, as opposed to other between study differences. Four experiments directly compared the learning of novel words using explicit and implicit methods, namely phoneme monitoring on isolated tokens vs. Hebb repetition of syllable sequences. The impact of the learning was tested at a range of later time-points using two tests of explicit knowledge (recognition and recall) and a test of lexical integration (pause detection on related existing words). Between experiments, we also manipulated exposure frequency, the impact of syllable grouping cues in Hebb repetition and the level of mismatch between novel and real words. The results suggested that learning novel words via Hebb sequence repetition does not confer a benefit on lexical integration prior to or after sleep. We observed an engagement in lexical competition only in the case where a good level of explicit training was followed by a consolidation delay. Recognition and recall performance was generally poorer for Hebb learning. We conclude that Hebb-style implicit learning of words does not allow consolidation processes to be bypassed in lexical integration.

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Introduction: Cough is one of the most frequent symptoms reported to pulmonologists. The role of bronchoscopy in the diagnostic work-up of chronic cough is not clearly defined. The aim of this study was to evaluate the utility of fiberoptic bronchoscopy (FOB) and additional testing of samples collected during FOB in the differential diagnosis of chronic cough in adults. Material and methods: This was a single-center retrospective study. Out of 7115 conventional white light FOB examinations, we finally selected 198 with cough as the only indication. Results: In 40.9% of bronchoscopic examinations, no visible cause of cough was found. Visual signs of chronic bronchitis (CB) were detected in 57.6% of reports. Only in 3 cases (1.5%) bronchoscopy revealed a potential cause of chronic cough other than CB. Mycobacterium tuberculosis or other mycobacteria were spotted in none of the samples. In 91.1% of bronchoalveolar lavage (BAL) cytologic examinations, at least one cell count abnormality was detected, but only in case of increased percentage of eosinophils, it might be considered clinically relevant. In 53% of bacteriological culture results, at least one potentially pathogenic bacterium was isolated. Conclusions: The present study results strengthen the evidence that FOB combined with additional testing of airway specimens obtained during FOB is not a powerful tool in the differential diagnosis of chronic cough, and FOB as a diagnostic tool may be overused. The appropriate timing and decision regarding referral for FOB and additional testing of achieved material requires careful clinical consideration.