Locations of objects are better remembered than their identities in naturalistic scenes:An eye-tracking experiment in mild cognitive impairment

Objective: Retaining the identity or location of decontextualized objects in visual short-term working memory (VWM) is impaired by healthy and pathological ageing, but research remains inconclusive on whether these two features are equally impacted by it. Moreover, it is unclear whether similar impairments would manifest in naturalistic visual contexts. Method: 30 people with mild cognitive impairment (MCI) and 32 age-matched control participants (CPs) were eye-tracked within a change detection paradigm. They viewed 120 naturalistic scenes, and after a retention interval (1 s) asked whether a critical object in the scene had (or not) changed on either: identity (became a different object), location (same object but changed location), or both (changed in location and identity). Results: MCIs performed worse than CP but there was no interaction with the type of change. Changes in both were easiest while changes in identity alone were hardest. The latency to first fixation and first-pass duration to the critical object during successful recognition was not different between MCIs and CPs. Objects that changed in both features took longer to be fixated for the first time but required a shorter first pass compared to changes in identity alone which displayed the opposite pattern. Conclusions: Locations of objects are better remembered than their identities; memory for changes is best when involving both features. These mechanisms are spared by pathological ageing as indicated by the similarity between groups besides trivial differences in overall performance. These findings demonstrate that VWM mechanisms in the context of naturalistic scene information are preserved in people with MCI.info:eu-repo/semantics/acceptedVersio

Unidimensional and Multidimensional Methods for Recurrence Quantification Analysis with crqa

Recurrence quantification analysis is a widely used method for characterizing patterns in time series. This article presents a comprehensive survey for conducting a wide range of recurrence-based analyses to quantify the dynamical structure of single and multivariate time series, and to capture coupling properties underlying leader-follower relationships. The basics of recurrence quantification analysis (RQA) and all its variants are formally introduced step-by-step from the simplest auto-recurrence to the most advanced multivariate case. Importantly, we show how such RQA methods can be deployed under a single computational framework in R using a substantially renewed version our crqa 2.0 package. This package includes implementations of several recent advances in recurrence-based analysis, among them applications to multivariate data, and improved entropy calculations for categorical data. We show concrete applications of our package to example data, together with a detailed description of its functions and some guidelines on their usage.Comment: Describes R package crqa v. 2.0: https://cran.r-project.org/web/packages/crqa

Typicality in the brain during semantic and episodic memory decisions

Typicality is a key semantic dimension supporting the categorical organization of items based on their features. Typical items share more features with other members of their category than atypical items, which are more distinctive. Typicality influences episodic recollection. Yet, the neural substrates of this effect have never been studied. This fMRI study investigated the neural correlates of typicality during semantic and episodic memory decisions . 26 subjects performed a categorization task on typical and atypical word concept and completed a recognition memory task. During the correct recognition of old items, regions from the core recollection network were activated, and typical items were reinstated more than atypical ones in several regions including the anterior temporal lobe. Results suggest that the centrality of this region in the processing of typicality extends to memory retrieval, and that the correct retrieval of typical items requires finer-grained, item-specific, processing, possibly to resolve their greater confusability with other category members.</p

Multilevel behavioral synchronization in a joint tower-building task

Human to Human sensorimotor interaction can only be fully understood by modeling the patterns of bodily synchronization and reconstructing the underlying mechanisms of optimal cooperation. We designed a tower-building task to address such a goal. We recorded upper body kinematics of dyads and focused on the velocity profiles of the head and wrist. We applied Recurrence Quantification Analysis to examine the dynamics of synchronization within, and across the experimental trials, to compare the roles of leader and follower. Our results show that the leader was more auto-recurrent than the follower to make his/her behavior more predictable. When looking at the cross-recurrence of the dyad, we find different patterns of synchronization for head and wrist motion. On the wrist, dyads synchronized at short lags, and such pattern was weakly modulated within trials, and invariant across them. Head motion instead, synchronized at longer lags and increased both within and between trials: a phenomenon mostly driven by the leader. Our findings point at a multilevel nature of human to human sensorimotor synchronization, and may provide an experimentally solid benchmark to identify the basic primitives of motion, which maximize behavioral coupling between humans and artificial agents

Fixation-related Brain Potentials during Semantic Integration of Object–Scene Information

In vision science, a particularly controversial topic is whether and how quickly the semantic information about objects is available outside foveal vision. Here, we aimed at contributing to this debate by coregistering eye movements and EEG while participants viewed photographs of indoor scenes that contained a semantically consistent or inconsistent target object. Linear deconvolution modeling was used to analyze the ERPs evoked by scene onset as well as the fixation-related potentials (FRPs) elicited by the fixation on the target object (t) and by the preceding fixation (t − 1). Object–scene consistency did not influence the probability of immediate target fixation or the ERP evoked by scene onset, which suggests that object–scene semantics was not accessed immediately. However, during the subsequent scene exploration, inconsistent objects were prioritized over consistent objects in extrafoveal vision (i.e., looked at earlier) and were more effortful to process in foveal vision (i.e., looked at longer). In FRPs, we demonstrate a fixation-related N300/N400 effect, whereby inconsistent objects elicit a larger frontocentral negativity than consistent objects. In line with the behavioral findings, this effect was already seen in FRPs aligned to the pretarget fixation t − 1 and persisted throughout fixation t, indicating that the extraction of object semantics can already begin in extrafoveal vision. Taken together, the results emphasize the usefulness of combined EEG/eye movement recordings for understanding the mechanisms of object–scene integration during natural viewing

Disentangling stimulus plausibility and contextual congruency: Electrophysiological evidence for differential cognitive dynamics

Expectancy mechanisms are routinely used by the cognitive system in stimulus processing and in anticipation of appropriate responses. Electrophysiology research has documented negative shifts of brain activity when expectancies are violated within a local stimulus context (e.g., reading an implausible word in a sentence) or more globally between consecutive stimuli (e.g., a narrative of images with an incongruent end). In this EEG study, we examine the interaction between expectancies operating at the level of stimulus plausibility and at more global level of contextual congruency to provide evidence for, or against, a disassociation of the underlying processing mechanisms. We asked participants to verify the congruency of pairs of cross-modal stimuli (a sentence and a scene), which varied in plausibility. ANOVAs on ERP amplitudes in selected windows of interest show that congruency violation has longer-lasting (from 100 to 500 ms) and more widespread effects than plausibility violation (from 200 to 400 ms). We also observed critical interactions between these factors, whereby incongruent and implausible pairs elicited stronger negative shifts than their congruent counterpart, both early on (100-200 ms) and between 400-500 ms. Our results suggest that the integration mechanisms are sensitive to both global and local effects of expectancy in a modality independent manner. Overall, we provide novel insights into the interdependence of expectancy during meaning integration of cross-modal stimuli in a verification task.Fundacao para a Ciencia e Tecnologia [SFRH/BPD/88374/2012, PTDC/PSI-PCO/110734/2009, UID/BIM/04773/2013 CBMR 1334, PEst-OE/EQB/LA0023/2013, UID/PSI/00050/2013]; Leverhulme Trust [ECF-2014-205]; Max Planck Institute for Psycholinguistics; Donders Institute for Brain, Cognition and Behaviourhttp://creativecommons.org/licenses/by/4.0

Standalone vertex finding in the ATLAS muon spectrometer

A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson