Inhibition and working memory capacity modulate the mental space-time association

This research aimed to investigate whether the mental space-time association of temporal concepts could be modulated by the availability of cognitive resources (in terms of working memory and inhibitory control capacities) and to explore whether access to this association could be an automatic process. To achieve this, two experiments were carried out. In Experiment 1, participants had to classify words with future and past meanings. The working memory load (high vs. low) was manipulated and the participants were grouped into quartiles according to their visuospatial working memory capacity (WMC). Temporal concepts were displayed subliminally (immediate masking) and supraliminally (delayed masking). The ANOVA showed a performance pattern consistent with the left-past right-future conceptual scheme, regardless of both the type of masking and the working memory load, except in high WMC participants, in which, interestingly, the space-time association effect was absent. In Experiment 2, participants were asked to respond to the colour of the font of the temporal words, and their attentional control capacity was assessed. The results indicated a timeline effect that was irrespective of the WM load and the type of perceptual processing, but not of the WM capacity or the inhibitory abilities. These findings partially endorse the automatic and implicit access to the mental space-time association and suggest the involvement of the availability of cognitive resources. Individual WMC differences appear to modulate the automatic nature of the effect rather than the processing conditions themselves.

Cognitive inhibition abilities explain inter-individual variability in gender-space associations

There is a great deal of research describing the close association that exists between numerical and spatial representations, illustrating the SNARC (Spatial-Numerical Association of Response Code) effect. This effect signals the spatial mental representation of small numbers to the left and larger numbers to the right, coinciding with the direction of reading and writing. Subsequent research has found a similar spatial representation for other stimuli (e.g., size of objects and animals, and words associated with time). Some of these spatially represented stimuli are social in nature, even suggesting a spatial mental organization of stimuli based on gender (e.g., the upper part of a vertical axis for males and the lower part for females). The aim of the present study was threefold (1) to replicate and extend results on the existence of a mental gender line (as a function of response hand: female-left hand and male-right hand) when responding simply to gender of stimuli; (2) to explore the influence of inhibitory control; and, (3) to determine whether gender-space associations depend on the explicit or implicit nature of a gender task. Three experiments were designed to pursue these objectives. In Experiment 1, female, male and neutral faces and names were displayed, and the participants were asked to identify their gender. Experiment 2, which also included a Stroop task, followed the same procedure as Experiment 1, but displayed objects that could be designated as female or male and others not related to any gender. Finally, in Experiment 3, in which participants were asked to respond to the direction of an arrow, object gender was not relevant to the task. Consistent with previous research and confirming our hypotheses, the results showed a spatial mental representation of the stimuli based on gender in all three experiments, regardless of whether the stimulus was consciously perceived. Moreover, inhibitory ability showed a relationship with the gender-space line effect. The contributions and implications of this study are discussed, as are possible limitations and future lines of research.

Hospital-Wide SARS-CoV-2 seroprevalence in health care workers in a Spanish teaching hospital

Introduction

Methods

Results

Conclusions

Individual Differences in Working Memory Capacity Modulate Electrophysiological Correlates of Semantic Negative Priming From Single Words

In the present study, event-related potentials (ERPs) were registered during a semantic negative priming (NP) task in participants with higher and lower working memory capacity (WMC). On each trial participants had to actively ignore a briefly presented single prime word, which was followed either immediately or after a delay by a mask. Thereafter, either a semantically related or an unrelated target word was presented, to which participants made a semantic categorization judgment. The ignored prime produced a behavioral semantic NP in delayed (but not in immediate) masking trials, and only for participants with a higher-WMC. Both masking type and WMC also modulated ERP priming effects. When the ignored prime was immediately followed by a mask (which impeded its conscious identification) a reliable N400 modulation was found irrespective of participants' WMC. However, when the mask onset following the prime was delayed (thus allowing its conscious identification), an attenuation of a late positive ERP (LPC) was observed in related compared to unrelated trials, but only in the higher-WMC group showing reliable behavioral NP. The present findings demonstrate for the first time that individual differences in WMC modulate both behavioral measures and electrophysiological correlates of semantic NP.

Mixing properties of Al2O3(0001)-supportedM2O3andMM'O3monolayers (M,M' = Ti, V, Cr, Fe)

Considering the importance of sub-monolayer transition metal oxides supported on another oxide in many industrial processes, with the help of a DFT +Uapproach, we provide information on the structural and electronic properties of pureM₂O₃and mixedMM'O₃oxide monolayers (M,M' = Ti, V, Cr, Fe) supported on anα-Al₂O₃(0001) support. With their structure in the prolongation of the alumina corundum lattice, the monolayers have non-equivalent surface and interface cations, which leads to two different cation configurations in the mixed oxides. In all cases, the interfacial charge transfer is weak, but strong cation-cation electron redistributions may take place as in TiVO₃, TiFeO₃, VFeO₃, and TiCrO₃in which actual redox processes lead to cation oxidation states different from the expected +3 value. We show that the tendency to mixing relies on the interplay between two very different driving forces. Cation-cation redox reactions, in most cases, strongly stabilise mixed configurations, but preference for a given cation position in the monolayer, because of surface energy reasons, may strengthen, weaken or even block the mixing tendency. By comparison with results obtained in bulk ilmenite, in free-standing monolayers and in MLs deposited on transition metal substrates, we evidence the flexibility of their electronic structure as a function of size, dimensionality and nature of support, as a lever to tune their properties for specific applications.

Modelling the precipitation of nanoparticles in a closed medium in the presence of seeds: Application to amorphous silica synthesis

Seed-mediated methods are widely used in industrial or academic laboratories for the synthesis of nanoparticles of controlled shape and size. In the natural medium, precipitation of secondary minerals also often take place on seeds. In this context, we have devised a formalism which accounts for the competition between seed growth and nucleation and growth of secondary particles in an initially over-saturated aqueous solution. Based on the classical nucleation theory, it involves a size-dependent growth law which accounts for Ostwald ripening effects, unlike most water-rock interaction codes. We find that, in such closed system, seed growth and nucleation/growth of secondary particles are strongly coupled. In the multi-dimensional parameter space, regions where one or the other process prevails are well-separated by a rather abrupt transition. In general, the value of the initial seed total surface area is insufficient to fully orientate the synthesis. Relying on this approach, we propose an alternative interpretation of recent experimental results on amorphous silica nanoparticle synthesis. Besides fundamental understanding of the kinetics of precipitation, the interest of the present approach is to serve as a guideline to experimentalists or industrialists working in seed-mediated syntheses and warn on the undesired formation of secondary particles when monodispersed distributions of nano- or micro-particles are searched.

Working memory capacity modulates expectancy-based strategic processing: Behavioral and electrophysiological evidence

The present research measured participants' event-related brain activity while they performed a Stroop-priming task that induced the implementation of expectancy-based strategic processes. Participants identified a colored (red vs. green) target patch preceded by a prime word (GREEN or RED), with incongruent prime-target pairings being more frequent (75 %) than congruent pairs (25 %). The prime-target stimulus onset asynchrony (SOA) was manipulated at two levels: 300 vs. 700 ms. Participants also performed a change localization task to assess their working memory capacity (WMC). At the 300 ms SOA, all participants presented a Stroop-priming congruency effect (slower responses on incongruent than on congruent trials) and an increased N2 amplitude in incongruent trials, irrespective of their WMC. At the 700-ms SOA, the lower-WMC group showed again a larger negative-going waveform to incongruent targets, whereas the higher-WMC group exhibited a reversed Stroop-priming congruency effect (faster responses to incongruent targets) and the N2 component was absent.

Hospital-Wide SARS-CoV-2 seroprevalence in health care workers in a Spanish teaching hospital

INTRODUCTION

Hospital-wide SARS-CoV-2 seroprevalence is rarely explored and can identify areas of unexpected risk. We determined the seroprevalence against SARS-CoV-2 in all health care workers (HCW) at a hospital.

METHODS

Cross-sectional study (14-27/04/2020). We determined SARS-CoV-2 IgG by ELISA in all HCW including external workers of a teaching hospital in Madrid. They were classified by professional category, working area, and risk for SARS-CoV-2 exposure.

RESULTS

Among 2919 HCW, 2590 (88,7%) were evaluated. The mean age was 43.8 years (SD 11.1), and 73.9% were females. Globally, 818 (31.6%) workers were IgG positive with no differences for age, sex or previous diseases. Of these, 48.5% did not report previous symptoms. Seropositivity was more frequent in high- (33.1%) and medium- (33.8%) than in low-risk areas (25.8%, p=0.007), but not for hospitalization areas attending COVID-19 and non-COVID-19 patients (35.5 vs 38.3% p>0.05). HWC with a previous SARS-CoV2 PCR-positive test were IgG seropositive in 90.8%. By multivariate logistic regression analysis seropositivity was significantly associated with being physicians (OR 2.37, CI95% 1.61-3.49), nurses (OR 1.67, CI95% 1.14-2.46), nurse assistants (OR 1.84, CI95% 1.24-2.73), HCW working at COVID-19 hospitalization areas (OR 1.71, CI95% 1.22-2.40), non-COVID-19 hospitalization areas (OR 1.88, CI95% 1.30-2.73), and at the Emergency Room (OR 1.51, CI95% 1.01-2.27).

CONCLUSIONS

Seroprevalence uncovered a high rate of infection previously unnoticed among HCW. Patients not suspected of having COVID-19 as well as asymptomatic HCW may be a relevant source for nosocomial SARS-CoV-2 transmission.

Semantic Negative Priming From an Ignored Single-Prime Depends Critically on Prime-Mask Inter-Stimulus Interval and Working Memory Capacity

The aim of this study is to examine the link between working memory capacity and the ability to exert cognitive control. Here, participants with either high or low working memory capacity (WMC) performed a semantic negative priming (NP) task as a measure of cognitive control. They were required to ignore a single prime word followed by a pattern mask appearing immediately or after a delay. The prime could be semantically related or unrelated to an upcoming target word where a forced-choice categorization was required. Each type of mask (immediate vs. delayed) appeared randomly from trial to trial. Results demonstrated that, when the ignored prime was immediately followed by the mask, neither of the groups (high or low WMC) showed reliable NP. In clear contrast, when the mask onset was delayed responses latencies were reliably slower for semantically related trials than for unrelated trials (semantic NP), but only for the high WMC group. The present results clearly demonstrate that semantic NP from single ignored primes depends on both the masking pattern that follows the prime (immediate vs. delayed mask), and on working memory capacity.

Shall We Dance? Dancing Modulates Executive Functions and Spatial Memory

BACKGROUND

Aging is generally considered to be related to physical and cognitive decline. This is especially prominent in the frontal and parietal lobes, underlying executive functions and spatial memory, respectively. This process could be successfully mitigated in certain ways, such as through the practice of aerobic sports. With regard to this, dancing integrates physical exercise with music and involves retrieval of complex sequences of steps and movements creating choreographies.

METHODS

In this study, we compared 26 non-professional salsa dancers (mean age 55.3 years, age-range 49-70 years) with 20 non-dancers (mean age 57.6 years, age-range 49-70 years) by assessing two variables: their executive functions and spatial memory performance.

RESULTS

results showed that dancers scored better that non-dancers in our tests, outperforming controls in executive functions-related tasks. Groups did not differ in spatial memory performance.

CONCLUSIONS

This work suggests that dancing can be a valid way of slowing down the natural age-related cognitive decline. A major limitation of this study is the lack of fitness assessment in both groups. In addition, since dancing combines multiple factors like social contact, aerobic exercise, cognitive work with rhythms, and music, it is difficult to determine the weight of each variable.

The implementation of expectancy-based strategic processes is delayed in normal aging

The present research examined if the time needed to implement expectancy-based strategic processes is different in younger and healthy older adults. In four experiments participants from both age groups performed different strategic priming tasks. These included a greater proportion of incongruent (or unrelated; 80%) than of congruent (or related; 20%) trials. With this procedure performance is worse for congruent (less frequent) than for incongruent (more frequent) trials, thus demonstrating that the relative frequency information can be used to predict the upcoming target. To explore the time course of these expectancy-based effects, the prime-target SOA was manipulated across experiments through a range of intervals: 400, 1000 and 2000 ms. Participants also performed a change localization and an antisaccade task to assess their working memory and attention control capacities. The results showed that increases in age were associated with (a) a slower processing-speed, (b) a decline in WM capacity, and (c) a decreased capacity for attentional control. The latter was evidenced by a disproportionate deterioration of performance in the antisaccade trials compared to the prosaccade ones in the older group. Results from the priming tasks showed a delay in the implementation of expectancies in older adults. Whereas younger participants showed strategic effects already at 1000 ms, older participants consistently failed to show expectancy-based priming during the same interval. Importantly, these effects appeared later at 2000 ms, being similar in magnitude to those by the younger participants and unaffected by task practice. The present findings demonstrate that the ability to implement expectancy-based strategies is slowed down in normal aging.

Ten years younger: Practice of chronic aerobic exercise improves attention and spatial memory functions in ageing

Aerobic exercise is associated with changes in brain morphology and improvement of cognitive functions. Physical activity may be especially important after age 60 when cognitive decline is more pronounced. In this paper, the effect of chronic practice of aerobic sports was studied in old adults by assessing their executive and mnesic functions, supported by frontal and temporal brain structures. Two groups were formed according to their age (60-69 and 70-79 years-old) including sportsmen (n = 23) and sedentary men (n = 24). Spatial memory and efficiency of attentional networks were measured, as well as general intelligence. Results showed that sportsmen outperformed sedentary participants in many of the tests employed. Thus their alerting, orienting and executive networks worked more effectively in the ANT-I task for executive functions, and they were more accurate in the spatial memory task, displaying a better spatial orientation. Scores in other neuropsychological tasks followed the same tendency. These data support the protective effect of aerobic exercise on cognitive functions.

The Influence of Working Memory Load on Expectancy-Based Strategic Processes in the Stroop-Priming Task

The present study investigated whether a differential availability of cognitive control resources as a result of varying working memory (WM) load could affect the capacity for expectancy-based strategic actions. Participants performed a Stroop-priming task in which a prime word (GREEN or RED) was followed by a colored target (red vs. green) that participants had to identify. The prime was incongruent or congruent with the target color on 80 and 20% of the trials, respectively, and participants were informed about the differential proportion of congruent vs. incongruent trials. This task was interleaved with a WM task, such that the prime word was preceded by a sequence of either a same digit repeated five times (low load) or five different random digits (high load), which should be retained by participants. After two, three, or four Stroop trials, they had to decide whether or not a probe digit was a part of the memory set. The key finding was a significant interaction between prime-target congruency and WM load: Whereas a strategy-dependent (reversed Stroop) effect was found under low WM load, a standard Stroop interference effect was observed under high WM load. These findings demonstrate that the availability of WM is crucial for implementing expectancy-based strategic actions.

Individual Differences in Working Memory Capacity Modulates Semantic Negative Priming from Single Prime Words

The present study investigated whether semantic negative priming from single prime words depends on the availability of cognitive control resources. Participants with high vs. low working memory capacity (as assessed by their performance in complex span and attentional control tasks) were instructed to either attend to or ignore a briefly presented single prime word that was followed by either a semantically related or unrelated target word on which participants made a lexical decision. Individual differences in working memory capacity (WMC) mainly affected the processing of the ignored primes, but not the processing of the attended primes: While the latter produced reliable positive semantic priming for both high- and low-WMC participants, the former gave rise to reliable semantic negative priming only for high WMC participants, with low WMC participants showing the opposite positive priming effect. The present results extend previous findings in demonstrating that (a) single negative priming can reliably generalize to semantic associates of the prime words, and (b) a differential availability of cognitive control resources can reliably modulate the negative priming effect at a semantic level of representation.

High and low schizotypal female subjects do not differ in spatial memory abilities in a virtual reality task

INTRODUCTION

Schizotypy is a psychological construct related to schizophrenia. The exact relationship between both entities is not clear. In recent years, schizophrenia has been associated with hippocampal abnormalities and spatial memory problems. The aim of this study was to determine possible links between high schizotypy (HS) and low schizotypy (LS) and spatial abilities, using virtual reality tasks. We hypothesised that the HS group would exhibit a lower performance in spatial memory tasks than the LS group.

METHODS

Two groups of female students were formed according to their score on the ESQUIZO-Q-A questionnaire. HS and LS subjects were tested on two different tasks: the Boxes Room task, a spatial memory task sensitive to hippocampal alterations and a spatial recognition task.

RESULTS

Data showed that both groups mastered both tasks. Groups differed in personality features but not in spatial performance. These results provide valuable information about the schizotypy-schizophrenia connections.

CONCLUSION

Schizotypal subjects are not impaired on spatial cognition and, accordingly, the schizotypy-schizophrenia relationship is not straightforward.

Precipitation mechanism of amorphous silica nanoparticles: a simulation approach

HYPOTHESIS

Despite its importance in numerous industrial and natural processes, many unsolved questions remain regarding the mechanism of silica precipitation in aqueous solutions: order of the reaction, role of silica oligomers, existence of an induction time and characteristics of the particle population. This may be traced back, in past models, to the lack of account of the first stages of nucleation, size dependence of the growth law, and full particle population. COMPUTATIONAL METHOD: A microscopic description of the nucleation and growth of amorphous silica nanoparticles is achieved which reproduces a large set of experimental measurements, under various thermodynamic conditions. The time evolution of the solution supersaturation and of the precipitate characteristics is established.

FINDINGS

A growth law of order 6 allows reproducing experimental results, without being correlated to the presence of silica oligomers in the aqueous solution. The saturation plateaus are shown not to be due to an induction period. The characteristics of the particle population are more complex than assumed by simple precipitation models (Johnson-Mehl-Avrami-Kolmogorov or Chronomal models) and strongly depend on how supersaturation is reached. Such a microscopic approach thus proves to be well suited to elucidate the mechanism of nanoparticle formation in natural and industrial contexts.

Temperament and negative semantic priming in children 7 to 12 years old

The present research assessed whether children with high and low scores on temperament traits differed in their ability to inhibit irrelevant task information in a lexical decision task. Children from 7 to 12 years old were classified based on temperament dimensions measured using a version of the Temperament in Middle Childhood Questionnaire. The participants were instructed to either attend to (and remember) or to ignore a masked prime word followed by a central probe target on which they made a lexical decision. The results revealed several notable outcomes. First of all, recognition memory was better for attended than ignored words, providing further evidence that attention instructions influenced the processing of the primes. Secondly, although no negative priming effect was obtained in the "ignore" condition, 43% of children showed this effect. Thirdly, children scoring high on Inhibitory Control and Impulsivity showed ignored negative priming, whereas children scoring high on Inhibitory Control and low on Impulsivity ignored facilitation. Data are discussed within the framework of negative priming as a complex phenomenon that involves the interaction of different factors such as age, type of task, and certain temperament traits.

Semantic priming effects from single words in a lexical decision task

The present research examines the semantic priming effects of a centrally presented single prime word to which participants were instructed to either "attend and remember" or "ignore". The prime word was followed by a central probe target on which the participants made a lexical decision task. The main variables manipulated across experiments were prime duration (50 or 100 ms), the presence or absence of a mask following the prime, and the presence (or absence) and type of distractor stimulus (random set of consonants or pseudowords) on the probe display. There was a consistent interaction between the instructions and the semantic priming effects. Relative to the "attend and remember" instruction, an "ignore" instruction produced reduced positive priming from single primes presented for 100 ms, irrespective of the presence or absence of a prime mask, and regardless of whether the probe target was presented with or without distractors. Additionally, reliable negative priming was found from ignored primes presented for briefer durations (50 ms) and immediately followed by a mask. Methodological and theoretical implications of the present findings for the extant negative priming literature are discussed.

Repetition priming effects from attended vs. ignored single words in a semantic categorization task

The present research examines priming effects from a centrally presented single-prime word to which participants were instructed to either attend or ignore. The prime word was followed by a single central target word to which participants made a semantic categorization (animate vs. inanimate) task. The main variables manipulated across experiments were attentional instructions (attend vs. ignore the prime word), presentation duration of the prime word (20, 50, 80 or 100 ms), prime-target stimulus onset asynchrony (SOA; 300 vs. 800 ms), and temporal presentation of instructions (before vs. after the prime word). The results showed (a) a consistent interaction between attentional instructions and repetition priming and (b) a qualitatively different ignored priming pattern as a function of prime duration: reduced positive priming (relative to the attend instruction) for prime exposures of 80 and 100 ms, and reliable negative priming for the shorter prime exposures of 20 and 50 ms. In addition (c), the differential priming pattern for attend and ignore trials was observed at a prime-target SOA of 800 ms (but not at a shorter 300-ms SOA) and only when instructions were presented before the prime word. Methodological and theoretical implications of the present findings for the extant negative priming literature are discussed.

Influence of prime-target relationship on semantic priming effects from words in a lexical-decision task

The present research examines the influence of prime-target relationship (associative and categorical versus categorical only) on priming effects from attended and ignored parafoveal words. Participants performed a lexical-decision task on a single central target, which was preceded by two parafoveal prime words, one of which (the attended prime) was spatially precued. The results showed reliable positive and negative priming effects from attended and ignored words, respectively. However, this priming pattern was observed only for the "associative and categorical", but not for the "categorical only" relationship condition. These results suggest that the lack of semantic priming effects from words in some prior studies may be attributed to the kind of material used (i.e. weakly-associated word pairs).

Influence of prime-probe stimulus onset asynchrony and prime precuing manipulations on semantic priming effects with words in a lexical-decision task

The present research examines semantic priming from attended and unattended parafoveal words. Participants made a lexical decision in response to a single central target. The target was preceded by two parafoveal prime words, with one of them (the attended prime) being precued by a peripheral cue. The main variables manipulated across experiments were cue informativeness (valid vs. neutral cues) and stimulus onset asynchrony (SOA) between prime and probe (200, 300, 600, or 1,000 ms). The results showed (a) reliable semantic priming from both attended and ignored prime words and (b) that the ignored priming effects were either negative or positive, depending on both the prime-probe SOA and cue informativeness. The present findings are discussed in relation to inhibitory versus episodic retrieval models of negative priming.