scholarly journals Informative and uninformative pre-stimulus encoding cues benefit source memory

2020 ◽  
Author(s):  
Nick Yeh ◽  
Joshua Koen

Research using both neuroimaging and psychophysiology show that neural activity elicited by an informative pre-stimulus cue predicts subsequent memory. However, it remains unclear whether pre-stimulus encoding cues actually benefit subsequent memory performance. We investigated this issue across three pre-registered experiments. At encoding, participants made one of two semantic judgments on words that were preceded by an informative pre-stimulus cue that identified the upcoming semantic judgment, an uninformative pre-stimulus cue that signaled an upcoming trial but no information about the semantic judgment, or no cue. There was little evidence that pre-stimulus cues improved old/new recognition discrimination or subjective estimates of recollection and familiarity derived from receiver operating characteristic curves. Importantly, both informative and uninformative pre-stimulus cues enhanced source memory accuracy for the encoding task compared to the no cue condition. These findings suggest that pre-stimulus cues can strengthen the processes that support successful memory encoding and benefit subsequent source memory.

2020 ◽  
Author(s):  
E. Song Liu ◽  
Joshua D. Koen ◽  
Michael D. Rugg

AbstractPre-stimulus subsequent memory effects (SMEs) – differences in neural activity preceding the onset of study items that are predictive of later memory performance – have consistently been reported in young adults. The present fMRI experiment investigated potential age-related differences in pre-stimulus SMEs. During study, healthy young and older participants made one of two semantic judgments on images, with the judgment signaled by a preceding cue. In the test phase, participants first made an item recognition judgment and, for each item judged old, a source memory judgment. Age-invariant pre-stimulus SMEs were observed in left dorsomedial prefrontal cortex, left hippocampus, and right subgenual cortex. In each case, the effects reflected lower BOLD signal for later recognized items, regardless of source accuracy, than unrecognized items. A similar age-invariant pattern was observed in left orbitofrontal cortex, but the effect in this region was specific to items attracting a correct source response compared to unrecognized items. In contrast, the left angular gyrus and fusiform cortex demonstrated negative pre-stimulus SMEs that were exclusive to young participants. The findings indicate that age differences in pre-stimulus SMEs are regionally specific and suggest that pre-stimulus SMEs reflect multiple cognitive processes, only some of which are vulnerable to advancing age.


2019 ◽  
Author(s):  
Ross Lawrence ◽  
Xiaoqian Chai

Self-referential memory encoding has been previously shown to enhance memory. The self-referential facilitation effect has also been found in source memory (memory with contextual details). In this study, we investigated how subjective recollection interacts with the self-referential effect for source memory. Using a remember/know paradigm, we compared source memory accuracy under self-referential encoding and semantic encoding. Two types of source information were included, a “peripheral” source which was not inherent to the encoding activity, and a source information about the encoding context. SRE benefits on source memory accuracy were observed in recollection for both types of source information, but not in familiarity-based memory. In contrast, for familiarity-based memory, semantic encoding resulted in higher source accuracy for the background source compared to self-referential encoding. These results suggest self-referential encoding creates a richer, more detailed memory trace which can be recollected later on.


2019 ◽  
Author(s):  
Christoph T. Weidemann ◽  
Michael J. Kahana

Human cognition exhibits a striking degree of variability: Sometimes we rapidly forge new associations whereas at other times new information simply does not stick. Correlations between neural activity during encoding and subsequent retrieval performance have implicated such “subsequent memory effects” (SMEs) as important for understanding the neural basis of memory formation. Uncontrolled variability in external factors that also predict memory performance, however, confounds the interpretation of these effects. By controlling for a comprehensive set of external variables, we investigated the extent to which neural correlates of successful memory encoding reflect variability in endogenous brain states. We show that external variables that reliably predict memory performance have relatively small effects on electroencephalographic (EEG) correlates of successful memory encoding. Instead, the brain activity that is diagnostic of successful encoding primarily reflects fluctuations in endogenous neural activity. These findings link neural activity during learning to endogenous states that drive variability in human cognition.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Lei Xi ◽  
Chunqing Yang

AbstractObjectivesThe main aim of the present study was to assess the diagnostic value of alpha-l-fucosidase (AFU) for hepatocellular carcinoma (HCC).MethodsStudies that explored the diagnostic value of AFU in HCC were searched in EMBASE, SCI, and PUBMED. The sensitivity, specificity, and DOR about the accuracy of serum AFU in the diagnosis of HCC were pooled. The methodological quality of each article was evaluated with QUADAS-2 (quality assessment for studies of diagnostic accuracy 2). Receiver operating characteristic curves (ROC) analysis was performed. Statistical analysis was conducted by using Review Manager 5 and Open Meta-analyst.ResultsEighteen studies were selected in this study. The pooled estimates for AFU vs. α-fetoprotein (AFP) in the diagnosis of HCC in 18 studies were as follows: sensitivity of 0.7352 (0.6827, 0.7818) vs. 0.7501 (0.6725, 0.8144), and specificity of 0.7681 (0.6946, 0.8283) vs. 0.8208 (0.7586, 0.8697), diagnostic odds ratio (DOR) of 7.974(5.302, 11.993) vs. 13.401 (8.359, 21.483), area under the curve (AUC) of 0.7968 vs. 0.8451, respectively.ConclusionsAFU is comparable to AFP for the diagnosis of HCC.


2021 ◽  
pp. 096228022199595
Author(s):  
Yalda Zarnegarnia ◽  
Shari Messinger

Receiver operating characteristic curves are widely used in medical research to illustrate biomarker performance in binary classification, particularly with respect to disease or health status. Study designs that include related subjects, such as siblings, usually have common environmental or genetic factors giving rise to correlated biomarker data. The design could be used to improve detection of biomarkers informative of increased risk, allowing initiation of treatment to stop or slow disease progression. Available methods for receiver operating characteristic construction do not take advantage of correlation inherent in this design to improve biomarker performance. This paper will briefly review some developed methods for receiver operating characteristic curve estimation in settings with correlated data from case–control designs and will discuss the limitations of current methods for analyzing correlated familial paired data. An alternative approach using conditional receiver operating characteristic curves will be demonstrated. The proposed approach will use information about correlation among biomarker values, producing conditional receiver operating characteristic curves that evaluate the ability of a biomarker to discriminate between affected and unaffected subjects in a familial paired design.


2021 ◽  
pp. 174702182110263
Author(s):  
Philippe Blondé ◽  
Marco Sperduti ◽  
Dominique Makowski ◽  
Pascale Piolino

Mind wandering, defined as focusing attention toward task unrelated thoughts, is a common mental state known to impair memory encoding. This phenomenon is closely linked to boredom. Very few studies, however, have tested the potential impact of boredom on memory encoding. Thus, the present study aimed at manipulating mind wandering and boredom during an incidental memory encoding task, to test their differential impact on memory encoding. Thirty-two participants performed a variant of the n-back task in which they had to indicate if the current on-screen object was the same as the previous one (1-back; low working memory load) or the one presented three trials before (3-back; high working memory load). Moreover, thought probes assessing either mind wandering or boredom were randomly presented. Afterward, a surprise recognition task was delivered. Results showed that mind wandering and boredom were highly correlated, and both decreased in the high working memory load condition, while memory performance increased. Although both boredom and mind wandering predicted memory performance taken separately, we found that mind wandering was the only reliable predictor of memory performance when controlling for boredom and working memory load. Model comparisons also revealed that a model with boredom only was outperformed by a model with mind wandering only and a model with both mind wandering and boredom, suggesting that the predictive contribution of boredom in the complete model is minimal. The present results confirm the high correlation between mind wandering and boredom and suggest that the hindering effect of boredom on memory is subordinate to the effect of mind wandering.


2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Bo Yao ◽  
Wen-juan Liu ◽  
Di Liu ◽  
Jin-yan Xing ◽  
Li-juan Zhang

Abstract Background Early diagnosis of sepsis is very important. It is necessary to find effective and adequate biomarkers in order to diagnose sepsis. In this study, we compared the value of sialic acid and procalcitonin for diagnosing sepsis. Methods Newly admitted intensive care unit patients were enrolled from January 2019 to June 2019. We retrospectively collected patient data, including presence of sepsis or not, procalcitonin level and sialic acid level. Receiver operating characteristic curves for the ability of sialic acid, procalcitonin and combination of sialic acid and procalcitonin to diagnose sepsis were carried out. Results A total of 644 patients were admitted to our department from January 2019 to June 2019. The incomplete data were found in 147 patients. Finally, 497 patients data were analyzed. The sensitivity, specificity and area under the curve for the diagnosis of sepsis with sialic acid, procalcitonin and combination of sialic acid and procalcitonin were 64.2, 78.3%, 0.763; 67.9, 84.0%, 0.816 and 75.2, 84.6%, 0.854. Moreover, sialic acid had good values for diagnosing septic patients with viral infection, with 87.5% sensitivity, 82.2% specificity, and 0.882 the area under the curve. Conclusions Compared to procalcitonin, sialic acid had a lower diagnostic efficacy for diagnosing sepsis in critically ill patients. However, the combination of sialic acid and procalcitonin had a higher diagnostic efficacy for sepsis. Moreover, sialic acid had good value for diagnosing virus-induced sepsis.


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