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It is well-known that visual search for a mirror target (i.e., a horizontally flipped item) is more difficult than search for other-oriented items (e.g., vertically flipped items). Previous studies have typically attributed costs of mirror search to early, attention-guiding processes but could not rule out contributions from later processes. In the present study we used eye tracking to distinguish between early, attention-guiding processes and later target identification processes. The results of four experiments revealed a marked human weakness in identifying mirror targets: Observers appear to frequently fail to classify a mirror target as a target on first fixation and to continue with search even after having directly looked at the target. Awareness measures corroborated that the location of a mirror target could not be reported above chance level after it had been fixated once. This mirror blindness effect explained a large proportion (45–87%) of the overall costs of mirror search, suggesting that part of the difficulties with mirror search are rooted in later, object identification processes (not attentional guidance). Mirror blindness was significantly reduced but not completely eliminated when both the target and non-targets were held constant, which shows that perfect top-down knowledge can reduce mirror blindness, without completely eliminating it. The finding that nontarget certainty reduced mirror blindness suggests that object identification is not solely achieved by comparing a selected item to a target template. These results demonstrate that templates that guide search toward targets are not identical to the templates used to conclusively identify those targets.

Cerebellar output has been shown to enhance movement precision by scaling the decelerative phase of reaching movements in mice. We hypothesized that during reach, initial kinematics cue late-phase adjustments through cerebellar associative learning. We identify a population-level response in mouse PCs that scales inversely with reach velocity, suggesting a candidate mechanism for anticipatory control to target limb endpoint. We next interrogate how such a response is generated by combining high-density neural recordings with closed-loop optogenetic stimulation of cerebellar mossy fiber afferents originating in the pontine nuclei during reach, using perturbation schedules reminiscent of classic adaptation paradigms. We found that reach kinematics and PC electrophysiology adapt to position-locked mossy fiber perturbations and exhibit aftereffects when stimulation is removed. Surprisingly, we observed partial adaptation to position-randomized stimulation schedules but no opposing aftereffect. A model that recapitulated these findings provided novel insight into how the cerebellum deciphers cause-and-effect relationships to adapt.

Previous research on emotional face processing has shown that emotional faces such as fearful faces may be processed without visual awareness. However, evidence for nonconscious attention capture by fearful faces is limited. In fact, studies using sensory manipulation of awareness (e.g., backward masking paradigms) have shown that fearful faces do not attract attention during subliminal viewings nor when they were task-irrelevant. Here, we used a three-phase inattentional blindness paradigm and electroencephalography to examine whether faces (fearful and neutral) capture attention under different conditions of awareness and task-relevancy. We found that the electrophysiological marker for attention capture, the N2-posterior-contralateral (N2pc), was elicited by face stimuli only when participants were aware of the faces and when they were task-relevant (phase 3). When participants were unaware of the presence of faces (phase 1) or when the faces were irrelevant to the task (phase 2), no N2pc was observed. Together with our previous work, we concluded that fearful faces, or faces in general, do not attract attention unless we want them to.

Objective The aim of this study was to compare and characterize the structural and ultrastructural organization of the temporomandibular joint (TMJ) between two large animal models for use in the development of tissue engineering strategies. Materials and methods Whole TMJs from sheep and pigs were evaluated with micro-computed tomography (μCT) for morphology and quantitative analyses of bone parameters. Histological examination was performed on the TMJ disc and its attachments to investigate regional distribution of collagen, elastin, and glycosaminoglycans (GAGs). Results μCT analyses demonstrate higher bone mineral density (BMD) in the temporal fossa compared to the mandibular condyle in both species, with this variable being significantly higher in sheep than pig. Quantitative morphometry of the trabecular condyle reveals no statistical differences between the species. Histology demonstrates similar structural organization of collagen and elastin between species. Elastin staining was nearly twofold greater in sheep than in the pig disc. Finally, Safranin-O staining for GAGs in the TMJ disc was localized to the intermediate zone in the sheep but was absent from the porcine disc. Conclusions Our findings show some important differences in the pig and sheep TMJ μCT variables and histology and composition of the disc and discal attachment. These disparities likely reflect differences in masticatory and TMJ functional loading patterns between the two species and provide insights into large animal models towards human applications. Clinical relevance As with the established pig model, the sheep is a suitable large animal model for TMJ research such as regenerative strategies, with specific considerations for design parameters appropriate for human-analog applications.

Brain electroencephalography (EEG), the complex, weak, multivariate, nonlinear, and nonstationary time series, has been recently widely applied in neurocognitive disorder diagnoses and brain-machine interface developments. With its specific features, unlabeled EEG is not well addressed by conventional unsupervised time-series learning methods. In this article, we handle the problem of unlabeled EEG time-series clustering and propose a novel EEG clustering algorithm, that we call mwcEEGc. The idea is to map the EEG clustering to the maximum-weight clique (MWC) searching in an improved Fréchet similarity-weighted EEG graph. The mwcEEGc considers the weights of both vertices and edges in the constructed EEG graph and clusters EEG based on their similarity weights instead of calculating the cluster centroids. To the best of our knowledge, it is the first attempt to cluster unlabeled EEG trials using MWC searching. The mwcEEGc achieves high-quality clusters with respect to intracluster compactness as well as intercluster scatter. We demonstrate the superiority of mwcEEGc over ten state-of-the-art unsupervised learning/clustering approaches by conducting detailed experimentations with the standard clustering validity criteria on 14 real-world brain EEG datasets. We also present that mwcEEGc satisfies the theoretical properties of clustering, such as richness, consistency, and order independence.

In the current EEG study, we used a dot-probe task in conjunction with backward masking to examine the neural activity underlying awareness and spatial processing of fearful faces and the neural processes for subsequent cued spatial targets. We presented face images under different viewing conditions (subliminal and supraliminal) and manipulated the relation between a fearful face in the pair and a subsequent target. Our mass univariate analysis showed that fearful faces elicit the N2-posterior-contralateral, indexing spatial attention capture, only when they are presented supraliminally. Consistent with this, the multivariate pattern analysis revealed a successful decoding of the location of the fearful face only in the supraliminal viewing condition. Additionally, the spatial attention capture by fearful faces modulated the processing of subsequent lateralised targets that were spatially congruent with the fearful face, in both al and electrophysiological data. There was no evidence for nonconscious processing of the fearful faces in the current paradigm. We conclude that spatial attentional capture by fearful faces requires visual awareness and it is modulated by top-down task demands.

Visual working memory (VWM) allows for the brief retention of approximately three to four items. Interestingly, when these items are similar to each other in a feature domain, memory recall performance is elevated compared to when they are dissimilar. This similarity benefit is currently not accounted for by models of VWM. Previous research has suggested that this similarity benefit may arise from selective attentional prioritisation in the maintenance phase. However, the similarity effect has not been contrasted under circumstances where dissimilar item types can adequately compete for memory resources. In Experiment 1, similarity benefits were seen for all-similar over all-dissimilar displays. This was also seen in mixed displays, change detection performance was higher when one of the two similar items changed, compared to when the dissimilar item changed. Surprisingly, the similarity effect was stronger in these mixed displays then when comparing the all-similar and all-dissimilar. Experiment 2 investigated this further by examining how attention was allocated in the memory encoding phase via eye movements. Results revealed that attention prioritised similar over dissimilar items in the mixed displays. Similar items were more likely to receive the first fixation and were fixated more often than dissimilar items. Furthermore, dwell times were elongated for dissimilar items, suggesting that encoding was less efficient. These results suggest that there is an attentional strategy towards prioritising similar items over dissimilar items, and that this strategy’s influence can be observed in the memory encoding phase.

It has been repeatedly claimed that emotional faces capture attention readily, and that they are processed without awareness. Yet some observations cast doubt on these assertions. Part of the problem may lie in the experimental paradigms employed. Here, we used a free viewing visual search task and simultaneously recorded electroencephalography and eye-movements. Fixation-related potentials were computed for fearful and neutral facial expressions, and the electrical response compared when participants were aware or unaware of the fixated stimulus. We showed that the P300 increased across repeated fixations on the unseen targets, culminating in a conscious report, likely reflecting evidence accumulation. Awareness of the stimulus was associated with electrical changes emerging at around 130 ms, with emotions of the stimulus being dissociated only after awareness had arisen. These results suggest that the earliest electrical correlate of awareness emerges at around 130 ms in visual search and that emotion processing requires visual awareness.

Voxel-wise meta-analyses of task-evoked regional activity were conducted for healthy individuals during the unconscious processing of emotional and neutral faces with an aim to examine whether and how different experimental paradigms influenced brain activation patterns. Studies were categorized into sensory and attentional unawareness paradigms. Thirty-four fMRI studies including 883 healthy participants were identified. Across experimental paradigms, unaware emotional faces elicited stronger activation of the limbic system, striatum, inferior frontal gyrus, insula and the temporal lobe, compared to unaware neutral faces. Crucially, in attentional unawareness paradigms, unattended emotional faces elicited a right-lateralized increased activation (i.e., right amygdala, right temporal pole), suggesting a right hemisphere dominance for processing emotional faces during inattention. By contrast, in sensory unawareness paradigms, unseen emotional faces elicited increased activation of the left striatum, the left amygdala and the right middle temporal gyrus. Additionally, across paradigms, unconsciously processed positive emotions were found associated with more activation in temporal and parietal cortices whereas unconsciously processed negative emotions elicited stronger activation in subcortical regions, compared to neutral faces.

The paper deals with the investigation of magneto-sensitive elastomers (MSE) and their application in technical actuator systems. MSE consist of an elastic matrix containing suspended magnetically soft and/or hard particles. Additionally, they can also contain silicone oil, graphite particles, thermoplastic components, etc., in various concentrations in order to tune specific properties such as viscosity, conductivity and thermoelasticity, respectively. The focuses of investigations are the beneficial properties of MSE in prototypes for locomotion and manipulation purposes that possess an integrated sensor function. The research follows the principle of a model-based design, i.e. the working steps are ideation, mathematical modelling, material characterization as well as building first functional models (prototypes). The developed apedal (without legs) and non-wheeled locomotion systems use the interplay between material deformations and the mechanical motion in connection with the issues of control and stability. Non-linear friction phenomena lead to a monotonous forward motion of the systems. The aim of this study is the design of such mechanical structures, which reduce the control costs. The investigations deal with the movement and control of ‘intelligent’ mechanisms, for which the magnetically field-controlled particle-matrix interactions provide an appropriate approach. The presented grippers enclose partially gripped objects, which is an advantage for handling sensitive objects. Form-fit grippers with adaptable contour at the contact area enable a uniform pressure distribution on the surface of gripped objects. Furthermore, with the possibility of active shape adaptation, objects with significantly differing geometries can be gripped. To realise the desired active shape adaptation, the effect of field-induced plasticity of MSE is used. The first developed prototypes mainly confirm the functional principles as such without direct application. For this, besides the ability of locomotion and manipulation itself, further technological possibilities have to be added to the systems. The first steps are therefore being taken towards integrated MSE based adaptive sensor systems.

Magnetoactive elastomers (MAEs) are a special type of smart materials consisting of an elastic matrix with embedded microsized particles that are made of ferromagnetic materials with high or low coercivity. Due to their composition, such elastomers possess unique magnetic field-dependent material properties. The present paper compiles the results of investigations on MAEs towards an approach of their potential application as vibrating sensor elements with adaptable sensitivity. Starting with the model-based and experimental studies of the free vibrational behavior displayed by cantilevers made of MAEs, it is shown that the first bending eigenfrequency of the cantilevers depends strongly on the strength of an applied uniform magnetic field. The investigations of the forced vibration response of MAE beams subjected to in-plane kinematic excitation confirm the possibility of active magnetic control of the amplitude-frequency characteristics. With change of the uniform field strength, the MAE beam reveals different steady-state responses for the same excitation, and the resonance may occur at various ranges of the excitation frequency. Nonlinear dependencies of the amplification ratio on the excitation frequency are obtained for different magnitudes of the applied field. Furthermore, it is shown that the steady-state vibrations of MAE beams can be detected based on the magnetic field distortion. The field difference, which is measured simultaneously on the sides of a vibrating MAE beam, provides a signal with the same frequency as the excitation and an amplitude proportional to the amplitude of resulting vibrations. The presented prototype of the MAE-based vibrating unit with the field-controlled “configuration” can be implemented for realization of acceleration sensor systems with adaptable sensitivity. The ongoing research on MAEs is oriented to the use of other geometrical forms along with beams, e.g. two-dimensional structures such as membranes.

A pendulum with an attached permanent magnet swinging in the vicinity of a conductor is a typical experiment for the demonstration of electromagnetic braking and Lenz’ law of induction. When the conductor itself moves, it can transfer energy to the pendulum. An exact analytical model of such an electromagnetic interaction is possible for a flat conducting plate. The eddy currents induced in the plate by a moving magnetic dipole and the resulting force and torque are known analytically in the quasistatic limit, i.e., when the magnetic diffusivity is sufficiently high to ensure an equilibrium of magnetic field advection and diffusion. This allows us to study a simple pendulum with a magnetic dipole moment in the presence of a horizontal plate oscillating in vertical direction. Equilibrium of the pendulum in the vertical position can be realized in three cases considered, i.e., when the magnetic moment is parallel to the rotation axis, or otherwise, its projection onto the plane of motion is either horizontal or vertical. The stability problem is described by a differential equation of Mathieu type with a damping term. Instability is only possible when the vibration amplitude and the distance between plate and magnet satisfy certain constraints related to the simultaneous excitation and damping effects of the plate. The nonlinear motion is studied numerically for the case when the magnetic moment and rotation axis are parallel. Chaotic behavior is found when the eigenfrequency is sufficiently small compared to the excitation frequency. The plate oscillation typically has a stabilizing effect on the inverted pendulum.

Recent attentional capture studies with the spatial cueing paradigm often found that target-dissimilar precues resulted in longer RTs on valid than invalid cue trials. These same location costs were accompanied by a contralateral positivity over posterior electrodes from 200 to 300 ms, similar to a PD component. Same location costs and the PD have been linked to the inhibition of cues with a unique feature (singleton cues) that do not match the target feature. In some studies reporting same location costs, the cue was surrounded by other cues (i.e., the context cues) that matched the physical or relative feature of the target. We hypothesized that the context cues might have captured attention and might have elicited data patterns that mimicked the inhibitory effects. To disentangle inhibition of the singleton cue from capture by the context cues, we added gray cues to the cue array, which we considered neutral because gray matched neither the target nor the nontarget color. In four experiments, the results consistently showed that the context cues in the nonmatching cue condition captured attention, as reflected in shorter RTs compared to neutral cues and a substantial N2pc to lateralized context cues. By contrast, the evidence for inhibition of the singleton cue was rather weak. Therefore, same location costs and lateralized positivity in the event-related potential of participants in several recent studies probably reflected attentional capture by the context cues, not inhibition of the singleton cue. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

A highly debated question in attention research is to what extent attention is biased by bottom-up factors such as saliency versus top-down factors as governed by the task. Visual search experiments in which participants are briefly familiarized with the task and then see a novel stimulus unannounced and for the first time support yet another factor, showing that novel and surprising features attract attention. In the present study, we tested whether gaze behavior as an indicator for attentional prioritization can be predicted accurately within displays containing both salient and novel stimuli by means of a priority map that assumes novelty as an additional source of activation. To that aim, we conducted a visual search experiment where a color singleton was presented for the first time in the surprise trial and manipulated the color-novelty of the remaining non-singletons between participants. In one group, the singleton was the only novel stimulus ("one-new"), whereas in another group, the non-singleton stimuli were likewise novel ("all-new"). The surprise trial was always target absent and designed such that top-down prioritization of any color was unlikely. The results show that the singleton in the all-new group captured the gaze less strongly, with more early fixations being directed to the novel non-singletons. Overall, the fixation pattern can accurately be explained by noisy priority maps where saliency and novelty compete for gaze control. Crown Copyright © 2020. Published by Elsevier Ltd. All rights reserved.

This article explores valid brain electroencephalography (EEG) selection for EEG classification with different classifiers, which has been rarely addressed in previous studies and is mostly ignored by existing EEG processing methods and applications. Importantly, traditional selection methods are not able to select valid EEG signals for different classifiers. This article focuses on a source control-based valid EEG selection to reduce the impact of invalid EEG signals and aims to improve EEG-based classification performance for different classifiers. We propose a novel centroid-based EEG selection approach named CenEEGs, which uses a scale-and-shift-invariance similarity metric to measure similarities of EEG signals and then applies a globally optimal centroid strategy to select valid EEG signals with respect to a similarity threshold. A detailed comparison with several state-of-the-art time series selection methods by using standard criteria on 8 EEG datasets demonstrates the efficacy and superiority of CenEEGs for different classifiers.

Context. Long-period variable stars (LPVs) are pulsating red giants, primarily in the asymptotic giant branch phase, and they include both Miras and semi-regular variables (SRVs). Their period-age and period-luminosity relations enable us to trace different stellar populations, as they are intrinsically very bright and cover a wide range in distances and ages. Aims. The purpose of this study is to establish a census of LPV stars in a region close to the Galactic center, using the six-year database of the Vista Variables in the Vía Láctea (VVV) ESO Public Survey, as well as to describe the methodology that was employed to search for and characterize LPVs using VVV data. Near-IR surveys such as VVV provide a unique opportunity to probe the high-extinction innermost regions of the Milky Way. The detection and analysis of the intrinsically bright Miras in this region could provide us with an excellent probe of the properties of the Milky Way far behind its bulge. Methods. We used point-spread function photometry for all available Ks-band images in ten VVV tiles, covering 16.4 deg2 in total, overlapping fields observed in the course of the Optical Gravitational Lensing Experiment (OGLE)-III survey. We designed a method to select LPV candidates, and we used the known variables from OGLE-III and other known variables from the literature to test our approach. The reduced χ2 statistic, along with the flux-independent index K(fi), were used in our analysis. The Lomb-Scargle period search method, Fourier analysis, template fitting, and visual inspection were then performed to refine our sample and characterize the properties of the stars included in our catalog. Results. A final sample of 130 Mira candidates, of which 129 are new discoveries, was thus obtained, with periods in the range between about 80 and 1400 days. Moreover, a sample of 1013 LPV candidates is also presented, whose periods are however not sufficiently constrained by the available data. A fraction of the latter may eventually turn out to be SRVs. Ages are measured for these stars based on a reassessment of the period-age relations available in the literature. The Miras in our catalog include 18 stars satisfying the requirements to serve as reliable distance indicators and which are not saturated in the VVV Ks-band images. Their distances are accordingly derived and discussed. A number of objects that are seemingly placed far behind the Milky Way’s bulge was detected.

It is well known that attention can be automatically attracted to salient items. However, recent studies show that it is possible to avoid distraction by a salient item (with a known feature), leading to facilitated search. This article tests a proposed mechanism for distractor inhibition: that a mental representation of the distractor feature held in visual working memory (VWM) allows attention to be guided away from the distractor. We tested this explanation by examining color-based inhibition in visual search for a shape target with and without VWM load. In Experiment 1 the presence of a distractor facilitated visual search under low and high VWM loads, as reflected in faster response times when the distractor was present (compared to absent), and in fewer eye movements to the salient distractor than the non-target items. However, the eye movement inhibition effect was noticeably weakened in the load conditions. Experiment 2 explored further, to distinguish between inhibition of the distractor color and activation of the (irrelevant) target color. Intermittently presenting single-color search trials that contained only either a target, distractor or a neutral-colored singleton revealed that the distractor color attracted attention less than the neutral color with and without VWM load. The target color, however, only attracted attention more than neutral colors under no load, whereas a VWM load completely eliminated this effect. This suggests that although VWM plays a role in guiding attention to the (irrelevant) target color, distractor-feature inhibition can operate independently.

Currently, electroencephalogram (EEG) is mostly analyzed in a supervised way, which requires EEG labels (e.g., EEG classification). With the ever-increasing amount of unlabeled/mislabeled EEG in neuropsychiatric disorder diagnosis, BCI, and rehabilitation, manually labeling of EEG data is a labor intensive and time-consuming process, and few labs have developed algorithms to analyze EEG in an unsupervised manner (i.e., EEG clustering). In this paper, we propose a cooperative game inspired approach to cluster multi-trial EEG data. The idea is to map multi-trial EEG clustering to the coalition formation in a cooperative game, and then identify cluster center (the EEG trial with highest Shapley value) and assign EEG trials into proper clusters based on their cross correlation-transformed Shapley values. We demonstrate the mapped EEG cooperative game is convex, and it leads to an algorithm for multi-trial EEG clustering named CoGEEGc. The CoGEEGc yields high-quality multi-trial EEG clustering with respect to intra-cluster compactness and inter-cluster scatter. We show that CoGEEGc outperforms 15 state-of-the-art EEG or time series clustering approaches through detailed experimentation on real-world multi-trial EEG datasets. Comparison against 15 methods with four theoretical properties of clustering further illustrates the superiority of CoGEEGc, as it satisfies two properties while other approaches only satisfy one.