Mechanisms of memory retrieval in slow-wave sleep : memory retrieval in slow-wave sleep

Study Objectives: Memories 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. Methods: In Experiment 1, participants associated words with verbal and non-verbal 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. Results: In Experiment 1, forgetting of cued (vs. non-cued) associations was reduced by TMR with verbal and non-verbal cues to similar extents. In Experiment 2, TMR with identical non-verbal cues reduced forgetting of cued (vs. non-cued) associations, replicating Experiment 1. However, TMR with non-identical verbal cues reduced forgetting of both cued and non-cued associations. Conclusions: These 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 non-identical verbal cues may utilise linguistic decoding mechanisms, resulting in widespread reactivation across a broad category of memories

The benefits of targeted memory reactivation for consolidation in sleep are contingent on memory accuracy and direct cue-memory associations

Objectives: To investigate how the effects of targeted memory reactivation (TMR) are influenced by memory accuracy prior to sleep and the presence or absence of direct cue-memory associations. Methods: 30 participants associated each of 50 pictures with an unrelated word and then with a screen location in two separate tasks. During picture-location training, each picture was also presented with a semantically related sound. The sounds were therefore directly associated with the picture locations but indirectly associated with the words. During a subsequent nap, half of the sounds were replayed in slow wave sleep (SWS) (TMR). The effect of TMR on memory for the picture locations (direct cue-memory associations) and picture-word pairs (indirect cue-memory associations) was then examined. Results: TMR reduced overall memory decay for recall of picture locations. Further analyses revealed a benefit of TMR for picture locations recalled with a low degree of accuracy prior to sleep, but not those recalled with a high degree of accuracy. The benefit of TMR for low accuracy memories was predicted by time spent in SWS. There was no benefit of TMR for memory of the picture-word pairs, irrespective of memory accuracy prior to sleep. Conclusions: 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

Is bronchoscopy always justified in diagnosis of haemoptysis? Response to the letter of Solidoro and Guerrera

non

The role of bronchoscopy in diagnosis of chronic cough in adults: a retrospective single-center study

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

Czy bronchoskopia jest zawsze niezbędna w diagnostyce krwioplucia?

WSTĘP: Bronchofiberoskopia jest często wykonywanym badaniem we wstępnej diagnostyce krwioplucia. Wiele danych wskazuje jednak na to, że badanie to nie zawsze dostarcza dodatkowych istotnych informacji, ponad te uzyskane z badań obrazowych. Z tego powodu przeprowadzono analizę, której celem było określenie przydatności bronchofiberoskopii w pierwszoplanowej diagnostyce krwioplucia. MATERIAŁ I METODY: Przedmiotem retrospektywnej analizy były wyniki badań bronchoskopowych wykonanych u pacjentów kierowanych do pracowni bronchoskopowej. Zawarto w niej jedynie te badania, w których wyłącznym wskazaniem było krwioplucie, wyłączając inne przyczyny z zakresu układu oddechowego. WYNIKI: Do ostatecznej analizy włączono 114 pacjentów. Mediana wieku wynosiła 59 lat (IQR: 46–64,75). Aktywne krwawienie stwierdzono w badaniu u 13 pacjentów (11,4%). Nie różnili się oni od pozostałych pod względem wieku: 59 (54–69) v. 59 (45–64) lat; W = 532,5, p = 0,27, oraz płci: c2 = 1,68, p = 0,2. Natomiast u 29 pacjentów (25,44%) w bronchofiberoskopii nie ujawniono żadnych nieprawidłowości. Pacjenci należący do tej grupy byli istotnie młodsi — 46 (34–62) v. 60 (53–67) lat; W = 782, p = 0,003. WNIOSKI: Mały odsetek wyników wskazujących na aktywne krwawienie sugeruje nadużywanie bronchofiberoskopii w diagnostyce krwioplucia. Wskazania do tego badania powinny być zrewidowane, w szczególności w grupie młodych pacjentów z niemasywnym krwiopluciem.WSTĘP: Bronchofiberoskopia jest często wykonywanym badaniem we wstępnej diagnostyce krwioplucia. Wiele danych wskazuje jednak na to, że badanie to nie zawsze dostarcza dodatkowych istotnych informacji, ponad te uzyskane z badań obrazowych. Z tego powodu przeprowadzono analizę, której celem było określenie przydatności bronchofiberoskopii w pierwszoplanowej diagnostyce krwioplucia. MATERIAŁ I METODY: Przedmiotem retrospektywnej analizy były wyniki badań bronchoskopowych wykonanych u pacjentów kierowanych do pracowni bronchoskopowej. Zawarto w niej jedynie te badania, w których wyłącznym wskazaniem było krwioplucie, wyłączając inne przyczyny z zakresu układu oddechowego. WYNIKI: Do ostatecznej analizy włączono 114 pacjentów. Mediana wieku wynosiła 59 lat (IQR: 46–64,75). Aktywne krwawienie stwierdzono w badaniu u 13 pacjentów (11,4%). Nie różnili się oni od pozostałych pod względem wieku: 59 (54–69) v. 59 (45–64) lat; W = 532,5, p = 0,27, oraz płci: c2 = 1,68, p = 0,2. Natomiast u 29 pacjentów (25,44%) w bronchofiberoskopii nie ujawniono żadnych nieprawidłowości. Pacjenci należący do tej grupy byli istotnie młodsi — 46 (34–62) v. 60 (53–67) lat; W = 782, p = 0,003. WNIOSKI: Mały odsetek wyników wskazujących na aktywne krwawienie sugeruje nadużywanie bronchofiberoskopii w diagnostyce krwioplucia. Wskazania do tego badania powinny być zrewidowane, w szczególności w grupie młodych pacjentów z niemasywnym krwiopluciem

Temperature Effects Explain Continental Scale Distribution of Cyanobacterial Toxins

Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect effects of temperature were the main drivers of the spatial distribution in the toxins produced by the cyanobacterial community, the toxin concentrations and toxin quota. Generalized linear models showed that a Toxin Diversity Index (TDI) increased with latitude, while it decreased with water stability. Increases in TDI were explained through a significant increase in toxin variants such as MC-YR, anatoxin and cylindrospermopsin, accompanied by a decreasing presence of MC-LR. While global warming continues, the direct and indirect effects of increased lake temperatures will drive changes in the distribution of cyanobacterial toxins in Europe, potentially promoting selection of a few highly toxic species or strains.Peer reviewe

The Role of Bronchoscopy in Diagnosis of Chronic Cough in Adults: A Retrospective Single-Center Study

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