Sleep and fear conditioning, extinction learning and extinction recall: a systematic review and meta-analysis of polysomnographic findings

2021 ◽  
pp. 101501
Author(s):  
Maya T. Schenker ◽  
Luke J. Ney ◽  
Lisa N. Miller ◽  
Kim L. Felmingham ◽  
Christian L. Nicholas ◽  
...  
2021 ◽  
Vol 2 (Supplement_1) ◽  
pp. A62-A62
Author(s):  
M Schenker ◽  
L Ney ◽  
L Miller ◽  
K Felmingham ◽  
C Nicholas ◽  
...  

Abstract Sleep may contribute to the long-lasting consolidation and processing of emotional memories. Experimental fear conditioning and extinction paradigms model the development, maintenance, and treatment of anxiety disorders. The literature provides compelling evidence for the involvement of rapid eye movement (REM) sleep in the consolidation of such memories. This meta-analysis correlated polysomnographic sleep findings with psychophysiological reactivity to the danger (CS+) and safety stimuli (CS-), to clarify the specific role of sleep stages before and after fear conditioning, extinction learning and extinction recall. Overall, there was evidence that more pre-learning sleep stage two and less slow wave sleep was associated with higher psychophysiological reactivity to the safety stimulus during extinction learning. Preliminary evidence found here support the role of REM sleep during the post-extinction consolidation sleep phase in clinical populations with disrupted sleep, but not in healthy controls. Furthermore, the meta-regressions found that sex moderated the associations between sleep and psychophysiological reactivity throughout the paradigm providing evidence for diverging correlations in male and females. Specifically, increased post-extinction REM was associated with poorer extinction and safety recall in females while the opposite was found in males. These results have implications for future research in the role of sleep in emotional memory processing.


2019 ◽  
Author(s):  
Gaëtan Mertens ◽  
Iris Engelhard

Whether fear conditioning can take place without contingency awareness is a topic of continuing debate and conflicting findings have been reported in the literature. This systematic review provides a critical assessment of the available evidence. Specifically, a search was conducted to identify articles reporting fear conditioning studies in which the contingency between conditioned stimuli (CS) and the unconditioned stimulus (US) was masked, and in which CS-US contingency awareness was assessed. A systematic assessment of the methodological quality of the included studies (k = 41) indicated that most studies suffered from methodological limitations (i.e., poor masking procedures, poor awareness measures, researcher degrees of freedom, and trial-order effects), and that higher quality predicted lower odds of studies concluding in favor of contingency unaware fear conditioning. Furthermore, meta-analytic moderation analyses indicated no evidence for a specific set of conditions under which contingency unaware fear conditioning can be observed. Finally, funnel plot asymmetry and p-curve analysis indicated evidence for publication bias. We conclude that there is no convincing evidence for contingency unaware fear conditioning.


2019 ◽  
Vol 50 (9) ◽  
pp. 1442-1451 ◽  
Author(s):  
Benjamin Suarez-Jimenez ◽  
Anton Albajes-Eizagirre ◽  
Amit Lazarov ◽  
Xi Zhu ◽  
Ben J. Harrison ◽  
...  

AbstractBackgroundEstablishing neurobiological markers of posttraumatic stress disorder (PTSD) is essential to aid in diagnosis and treatment development. Fear processing deficits are central to PTSD, and their neural signatures may be used as such markers.MethodsHere, we conducted a meta-analysis of seven Pavlovian fear conditioning fMRI studies comparing 156 patients with PTSD and 148 trauma-exposed healthy controls (TEHC) using seed-basedd-mapping, to contrast neural correlates of experimental phases, namely conditioning, extinction learning, and extinction recall.ResultsPatients with PTSD, as compared to TEHCs, exhibited increased activation in the anterior hippocampus (extending to the amygdala) and medial prefrontal cortex during conditioning; in the anterior hippocampus-amygdala regions during extinction learning; and in the anterior hippocampus-amygdala and medial prefrontal areas during extinction recall. Yet, patients with PTSD have shown an overall decreased activation in the thalamus during all phases in this meta-analysis.ConclusionFindings from this metanalysis suggest that PTSD is characterized by increased activation in areas related to salience and threat, and lower activation in the thalamus, a key relay hub between subcortical areas. If replicated, these fear network alterations may serve as objective diagnostic markers for PTSD, and potential targets for novel treatment development, including pharmacological and brain stimulation interventions. Future longitudinal studies are needed to examine whether these observed network alteration in PTSD are the cause or the consequence of PTSD.


2021 ◽  
Author(s):  
Yali Wei ◽  
Yan Meng ◽  
Na Li ◽  
Qian Wang ◽  
Liyong Chen

The purpose of the systematic review and meta-analysis was to determine if low-ratio n-6/n-3 long-chain polyunsaturated fatty acid (PUFA) supplementation affects serum inflammation markers based on current studies.


2020 ◽  
Vol 90 (5-6) ◽  
pp. 535-552 ◽  
Author(s):  
Mahdieh Abbasalizad Farhangi ◽  
Mahdi Vajdi

Abstract. Backgrounds: Central obesity, as a pivotal component of metabolic syndrome is associated with numerous co-morbidities. Dietary factors influence central obesity by increased inflammatory status. However, recent studies didn’t evaluate the association between central obesity and dietary inflammation index (DII®) that give score to dietary factors according to their inflammatory potential. In the current systematic review and meta-analysis, we summarized the studies that investigated the association between DII® with central obesity indices in the general populations. Methods: In a systematic search from PubMed, SCOPUS, Web of Sciences and Cochrane electronic databases, we collected relevant studies written in English and published until 30 October 2019. The population of included studies were apparently healthy subjects or individuals with obesity or obesity-related diseases. Observational studies that evaluated the association between DII® and indices of central obesity including WC or WHR were included. Results: Totally thirty-two studies were included; thirty studies were cross-sectional and two were cohort studies with 103071 participants. Meta-analysis of observational studies showed that higher DII® scores were associated with 1.81 cm increase in WC (Pooled weighted mean difference (WMD) = 1.813; CI: 0.785–2.841; p = 0.001). Also, a non-significant increase in the odds of having higher WC (OR = 1.162; CI: 0.95–1.43; p = 0.154) in the highest DII category was also observed. In subgroup analysis, the continent, dietary assessment tool and gender were the heterogeneity sources. Conclusion: The findings proposed that adherence to diets with high DII® scores was associated with increased WC. Further studies with interventional designs are necessary to elucidate the causality inference between DII® and central obesity indices.


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