Early and late indications of item-specific control in a Stroop mouse tracking study

Published: May 17, 2018Previous studies indicated that cognitive conflict continues to bias actions even after a movement has been initiated. The present paper examined whether cognitive control also biases actions after movement initiation. To this end, we had participants perform a Stroop task in which we manipulated the item-specific proportion of (in)congruent trials (80% congruent vs. 20% congruent). Importantly, participants responded via mouse movements, allowing us to evaluate various movement parameters: initiation times, movement times, and movement accuracy. Results showed that mouse movements were faster and more accurate during congruent trials compared to incongruent trials. Moreover, we observed that this congruency effect was larger for 80% congruent compared to 20% congruent items, which reflects itemspecific cognitive control. Notably, when responses were initiated very fast ± rendering virtually no time for stimulus processing before movement onset ± this item-specific control was observed only in movement times. However, for relatively slow initiated responses, item specific control was observed both in initiation and in movement times. These findings demonstrate that item-specific cognitive control biases actions before and after movement initiation.This work was supported by the Special Research Fund of Ghent University (BOF) (grant number: BOF13/24j/080). MFLR was supported in part by the Research Foundation ± Flanders (FWO) as a Pegasus Marie Curie Fellow (grant number: 1262214N) and by a BOF postdoctoral fellowship (grant number: BOF15/PDO/135). ELA was supported by the FWO (grant number: 12C4715N)

How does working memory enable number-induced spatial biases?

Number-space associations are a robust observation, but their underlying mechanisms remain debated. Two major accounts have been identified. First, spatial codes may constitute an intrinsic part of number representations stored in the brain – a perspective most commonly referred to as the Mental Number Line account. Second, spatial codes may be generated at the level of working memory when number (or other) representations are coordinated in function of a specific task. The aim of the current paper is twofold. First, whereas a pure Mental Number Line account cannot capture the complexity of observations reported in the literature, we here explore if and how a pure working memory account can suffice. Second, we make explicit (more than in our earlier work) the potential building blocks of such a working memory account, thereby providing clear and concrete foci for empirical efforts to test the feasibility of the account

Studies of submarine slope failures in the North Atlantic: Causes, timing and consequences

Submarine landslides are a significant geohazard to offshore infrastructure and coastal areas. They occur worldwide on the slopes of volcanic islands and continental margins. In the NE Atlantic, many large-scale Holocene and Pleistocene submarine landslides are located at the mouth of cross-shelf troughs and were probably triggered by earthquakes. Discussions on critical preconditioning processes for slope failure relate to cyclic sedimentation patterns during glacial periods, gas hydrate dissociation caused by changing pressure and temperature condition, and over-steepening due to toe erosion or uneven sedimentation patterns. However, the significant geological destabilizing processes leading to slope failure are still not fully understood and require further studies. The main objective of this thesis is to gain new insights about the initiation of submarine landslides and to identify which particular destabilizing preconditioning processes make slopes prone to failure. This aim is addressed by the reconstruction of the failure chronology of the newly discovered Fram Slide Complex, and by a numerical modeling approach that investigates a new preconditioning process related to gas hydrates. (...

Can we predict community-wide effects of herbicides from toxicity tests on macrophyte species?

Macrophyte communities play an essential role in the way freshwater ecosystems function. It is thus of great concern to understand how environmental factors, especially anthropogenic ones, influence their composition and diversity. The aim of this study was to examine whether the effects of a herbicide mixture (50% atrazine, 35% isoproturon, 15% alachlor) on single macrophyte species can be used to predict its impact at a community level. In a first experiment we tested the sensitivity of six species (Azolla filiculoides, Ceratophyllum demersum, Elodea canadensis, Lemna minor, Myriophyllum spicatum and Vallisneria spiralis) grown separately and exposed to 0.6–600 gL−1 of the herbicide mixture. In a second experiment, conducted in microcosms, we tested the effects of herbicides on macrophyte assemblages composed of the same six species exposed to 0, 6 or 60 gL−1 of the herbicide mixture. Species grown separately exhibited growth inhibition at 60 and 600 gL−1. At 600 gL−1 the sensitivity differed significantly between species. V. spiralis was the most resistant species, C. demersum, M. spicatum and E. canadensis exhibited intermediate sensitivities, and A. filiculoides and L. minor were the most sensitive species. In microcosms, community biomass and Shannon evenness index were reduced after 8 weeks at 60 gL−1. Communities also exhibited changes in their composition: the relative and absolute abundance of C. demersum increased at 6 gL−1, while the relative abundance of V. spiralis increased at 60 gL−1. These results are in agreement with the individual responses of these species to the herbicides. It is therefore concluded that short-term effects of herbicides on simple macrophyte communities can be predicted from the sensitivity of individual species. However, further investigations are required to examine whether longer term effects can be predicted as well, especially in more complex communities

Monitoring of the performance of an air-to-water heat pump under real operating conditions

Bakalářská práce na téma „Měření provozu tepelného čerpadla vzduch-voda za reálných podmínek“ se zabývá vyhodnocením provozu tepelného čerpadla v rodiném domě s následným zjištěním závislosti topného faktoru a tepelného výkonu na teplotě vzduchu. První část je věnovaná teorii tepelných čerpadel, jejich rozdělení a vysvětlení základních pojmů. Dále jsou porovnány vykonové charakteristiky a topný faktor různých výrobců tepelných čerpadel. V druhé části je popsán způsob měření reálného tepelného čerpadla, které je použito v rodinném domě, použité měřící přístroje a měřící postupy. V třetí části jsou naměřené hodnoty vyneseny do grafů a je provedené vyhodnocení naměřených veličin a tepelné čerpadlo je zkontrolováno z hlediska vhodnosti použití.he Bachelor´s thesis on „Monitoring of the performance of an air-to-water heat pump under real operating conditions“ deals with the evaluation of a heat pump operation in a family house with a subsequent finding of the dependence of the heating factor and thermal performance on air temperature. The first part is dedicated to the theory of heat pumps, their categorization and explanation of the basic concepts. Next, we compare the performance characteristics and the coefficient of performance of heat pumps from different manufacturers. In the second part we describe measurements of a real heat pump which is used in a family house, the measuring instruments used, and particular measuring procedures. The third part shows the measured values plotted on charts, the measured values are analyzed, and the heat pump is checked for its suitability.

Turning the mind’s eye inward: the interplay between selective attention and working memory

Historically, cognitive sciences have considered selective attention and working memory as largely separated cognitive functions. That is, selective attention as a concept is typically reserved for the processes that allow for the prioritization of specific sensory input, while working memory entails more central structures for maintaining (and operating on) temporary mental representations. However, over the last decades various observations have been reported that question such sharp distinction. Most importantly, information stored in working memory has been shown to modulate selective attention processing – and vice versa. At the theoretical level, these observations are paralleled by an increasingly dominant focus on working memory as (involving) the attended part of long-term memory, with some positions considering that working memory is equivalent to selective attention turned to long-term memory representations – or internal selective attention. This questions the existence of working memory as a dedicated cognitive function and raises the need for integrative accounts of working memory and attention. The next step will be to explore the precise implications of attentional accounts of WM for the understanding of specific aspects and characteristics of WM, such as serial order processing, its modality-specificity, its capacity limitations, its relation with executive functions, as well as the nature of attentional mechanisms involved. This research topic in Frontiers in Human Neuroscience aims at bringing together the latest insights and findings about the interplay between working memory and selective attention

The congruency sequence effect 3.0: a critical test of conflict adaptation

Over the last two decades, the congruency sequence effect (CSE) -the finding of a reduced congruency effect following incongruent trials in conflict tasks- has played a central role in advancing research on cognitive control. According to the influential conflict-monitoring account, the CSE reflects adjustments in selective attention that enhance task focus when needed, often termed conflict adaptation. However, this dominant interpretation of the CSE has been called into question by several alternative accounts that stress the role of episodic memory processes: feature binding and (stimulus-response) contingency learning. To evaluate the notion of conflict adaptation in accounting for the CSE, we construed versions of three widely used experimental paradigms (the colour-word Stroop, picture-word Stroop and flanker task) that effectively control for feature binding and contingency learning. Results revealed that a CSE can emerge in all three tasks. This strongly suggests a contribution of attentional control to the CSE and highlights the potential of these unprecedentedly clean paradigms for further examining cognitive control