Exploring the boundaries of post-retrieval extinction in healthy and anxious individuals

Human and non-human animal studies indicate that the reconsolidation of conditioned fear memories can be interrupted, and return of fear attenuated, using a paradigm of memory retrieval coupled with extinction called post-retrieval extinction (PRE). This series of studies examined the efficacy of PRE for attenuating the return of fear in healthy and anxious individuals in order to inform translation of PRE to the clinic. Study 1 was a meta-analysis of 16 comparisons of PRE versus extinction in healthy human participants. My hypothesis that PRE would be more efficacious than extinction in attenuating the return of fear was supported (effect size g = 0.40). This effect was moderated by factors potentially related to memory strength. Accordingly, in Study 2, I tested a strategy to strengthen fear memories using a compound unconditioned stimulus for use in a subsequent study of PRE (Study 3). I hypothesized that the use of a compound unconditioned stimulus would improve rates of acquisition and differential conditioning levels in healthy participants (N=143, M(SD) age=23.0 (9.8), 59% female). My results confirmed that the use of a compound unconditioned stimulus enhanced rates of acquisition, but contrary to my hypothesis, did not enhance differential conditioning levels among those meeting threshold values for conditioning. In Study 3, I tested the relative efficacy of PRE in 49 healthy and 43 anxious participants (M(SD) age=23.0 (8.0), 71% female) who received either one day of acquisition followed by PRE or extinction, or three days of acquisition followed by PRE. I hypothesized that PRE would be more efficacious than extinction in attenuating the reinstatement of fear for memories conditioned over one day, but not for stronger fear memories conditioned over three days. Contrary to my hypothesis, no effect of PRE was observed on reinstatement of fear for participants who received one day of acquisition. Furthermore, PRE was not more beneficial for anxious participants who received one day versus three days of acquisition. In sum, the PRE effect size from this study was near zero and at the 11th percentile of those observed by meta-analysis; future research should continue to examine moderators of PRE effects

Post-transcriptional knowledge in pathway analysis increases the accuracy of phenotypes classification

Motivation: Prediction of phenotypes from high-dimensional data is a crucial task in precision biology and medicine. Many technologies employ genomic biomarkers to characterize phenotypes. However, such elements are not sufficient to explain the underlying biology. To improve this, pathway analysis techniques have been proposed. Nevertheless, such methods have shown lack of accuracy in phenotypes classification. Results: Here we propose a novel methodology called MITHrIL (Mirna enrIched paTHway Impact anaLysis) for the analysis of signaling pathways, which has built on top of the work of Tarca et al., 2009. MITHrIL extends pathways by adding missing regulatory elements, such as microRNAs, and their interactions with genes. The method takes as input the expression values of genes and/or microRNAs and returns a list of pathways sorted according to their deregulation degree, together with the corresponding statistical significance (p-values). Our analysis shows that MITHrIL outperforms its competitors even in the worst case. In addition, our method is able to correctly classify sets of tumor samples drawn from TCGA. Availability: MITHrIL is freely available at the following URL: http://alpha.dmi.unict.it/mithril

Anomalous experiences are more prevalent among highly suggestible individuals who are also highly dissociative

Introduction: Predictive coding models propose that high hypnotic suggestibility confers a predisposition to hallucinate due to an elevated propensity to weight perceptual beliefs (priors) over sensory evidence. Multiple lines of research corroborate this prediction and demonstrate a link between hypnotic suggestibility and proneness to anomalous perceptual states. However, such effects might be moderated by dissociative tendencies, which seem to account for heterogeneity in high hypnotic suggestibility. We tested the prediction that the prevalence of anomalous experiences would be greater among highly suggestible individuals who are also highly dissociative. Methods: We compared high and low dissociative highly suggestible participants and low suggestible controls on multiple psychometric measures of anomalous experiences. Results: High dissociative highly suggestible participants reliably reported greater anomalous experiences than low dissociative highly suggestible participants and low suggestible controls, who did not significantly differ from each other. Conclusions: These results suggest a greater predisposition to experience anomalous perceptual states among high dissociative highly suggestible individuals

Object-based attention is accentuated by object reward association

Humans use selective attention to prioritize visual features, like color or shape, as well as discrete spatial locations, and these effects are sensitive to the experience of reward. Reward-associated features and locations are accordingly prioritized from early in the visual hierarchy. Attention is also sensitive to the establishment of visual objects: selection of one constituent object part often leads to prioritization of other locations on that object. But very little is known about the influence of reward on this object-based control of attention. Here we show in four experiments that reward prioritization and object prioritization interact in visual cognition to guide selection. Experiment 1 establishes groundwork for this investigation, showing that reward feedback does not negate object prioritization. In Experiment 2, we corroborate the hypothesis that reward prioritization and object prioritization emerge concurrently. In Experiment 3, we find that reward prioritization and object prioritization sustain and interact in extinction, when reward feedback is discontinued. We verify this interaction in Experiment 4, linking it to task experience rather than the strategic utility of the reward association. Results suggest that information gathered from locations on reward-associated objects gains preferential access to cognition. (PsycInfo Database Record (c) 2024 APA, all rights reserved).</p

Da BlogER: il blog di classe tra didattica disciplinare e comunicazioni alle famiglie

Lo scopo di questo contributo consiste nel descrivere due pratiche relative all’uso didattico del blog provenienti dalla comunità di BlogER. La prima pratica, centrata sull’insegnamento del latino, mostra un contesto di uso diffuso del blog all’interno della scuola. La seconda si caratterizza per l’importanza attribuita alla comunicazione con le famiglie e all’uso delle immagini

Interaction between visual attention and the processing of visual emotional stimuli in humans : eye-tracking, behavioural and event-related potential experiments

Past research has shown that the processing of emotional visual stimuli and visual attention are tightly linked together. In particular, emotional stimuli processing can modulate attention, and, reciprocally, the processing of emotional stimuli can be facilitated or inhibited by attentional processes. However, our understanding of these interactions is still limited, with much work remaining to be done to understand the characteristics of this reciprocal interaction and the different mechanisms that are at play. This thesis presents a series of experiments which use eye-tracking, behavioural and event-related potential (ERP) methods in order to better understand these interactions from a cognitive and neuroscientific point of view. First, the influence of emotional stimuli on eye movements, reflecting overt attention, was investigated. While it is known that the emotional gist of images attracts the eye (Calvo and Lang, 2004), little is known about the influence of emotional content on eye movements in more complex visual environments. Using eye-tracking methods, and by adapting a paradigm originally used to study the influence of semantic inconsistencies in scenes (Loftus and Mackworth, 1978), we found that participants spend more time fixating emotional than neutral targets embedded in visual scenes, but do not fixate them earlier. Emotional targets in scenes were therefore found to hold, but not to attract, the eye. This suggests that due to the complexity of the scenes and the limited processing resources available, the emotional information projected extra-foveally is not processed in such a way that it drives eye movements. Next, in order to better characterise the exogenous deployment of covert attention toward emotional stimuli, a sample of sub-clinically anxious individuals was studied. Anxiety is characterised by a reflexive attentional bias toward threatening stimuli. A dot-probe task (MacLeod et al., 1986) was designed to replicate and extend past findings of this attentional bias. In particular, the experiment was designed to test whether the bias was caused by faster reaction times to fear-congruent probes or slower reaction times to neutral-congruent probes. No attentional bias could be measured. A further analysis of the literature suggests that subliminal cue stimulus presentation, as used in our case, may not generate reliable attentional biases, unlike longer cue presentations. This would suggest that while emotional stimuli can be processed without awareness, further processing may be necessary to trigger reflexive attentional shifts in anxiety. Then the time-course of emotional stimulus processes and its modulation by attention was investigated. Modulations of the very early visual ERP C1 component by emotional stimuli (e.g. Pourtois et al., 2004; Stolarova et al., 2006), but also by visual attention (Kelly et al., 2008), were reported in the literature. A series of three experiments were performed, investigating the interactions between endogenous covert spatial attention and object-based attention with emotional stimuli processing in the C1 time window (50–100 ms). It was found that emotional stimuli modulated the C1 only when they were spatially attended and task-irrelevant. This suggests that whilst spatial attention gates emotional facial processing from the earliest stages, only incidental processing triggers a specific response before 100 ms. Additionally, the results suggest a very early modulation by feature-based attention which is independent from spatial attention. Finally, simulated and actual electroencephalographic data were used to show that modulations of early ERP and event-related field (ERF) components are highly dependent on the high-pass filter used in the pre-processing stage. A survey of the literature found that a large part of ERP/ERF reports (about 40%) use high-pass filters that may bias the results. More particularly, a large proportion of papers reporting very early modulations also use such filters. Consequently, a large part of the literature may need to be re-assessed. The work described in this thesis contributes to a better understanding of the links between emotional stimulus processing and attention at different levels. Using various experimental paradigms, this work confirms that emotional stimuli processing is not ‘automated’, but highly dependent on the focus of attention, even at the earlier stages of visual processing. Furthermore, the uncovered potential bias generated by filtering will help to improve the reliability and precision of research in the ERP/ERF field, and more particularly in studies looking at early effects

Analysis of the optical response of a SARS-CoV-2-directed colorimetric immunosensor

The optical response of different configurations of functionalized gold nanoparticles (f-AuNPs) and SARS-CoV-2 virions is simulated in order to explore the behavior of a colloidal solution containing 105–1013 virions/ml. The analysis herein reported is carried out for three concentration regimes: (i) low (≲108 virions/ml), (ii) intermediate (∼109–1010 virions/ml), and (iii) high (≳1011 virions/ml). Given the high binding effectiveness of f-AuNPs to virions, three different configurations are expected to arise: (i) virions completely surrounded by f-AuNPs, (ii) aggregates (dimers or trimers) of virions linked by f-AuNPs, and (iii) single f-AuNP surrounded by virions. It is demonstrated that 20 nm diameter gold nanoparticles functionalized against all three kinds of SARS-CoV-2 proteins (membrane, envelope, and spike) allow one to reach a limit of detection (LOD) of ∼106 virions/ml, whereas the use of only one kind of f-AuNP entails a ten-fold worsening of the LOD. It is also shown that the close proximity (∼5 nm) of the f-AuNP to the virions assumed throughout this analysis is essential to avoid the hook effect, thereby pointing out the importance of realizing an apt functionalization procedure that keeps thin the dielectric layer (e.g., proteins or aptamers) surrounding the gold nanoparticles