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Baoliang Lu - One of the best experts on this subject based on the ideXlab platform.
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a multimodal approach to estimating Vigilance using eeg and forehead eog
Journal of Neural Engineering, 2017Co-Authors: Weilong Zheng, Baoliang LuAbstract:OBJECTIVE:Covert aspects of ongoing user mental states provide key context information for user-aware human computer interactions. In this paper, we focus on the problem of estimating the Vigilance of users using EEG and EOG signals. APPROACH:The PERCLOS index as Vigilance annotation is obtained from eye tracking glasses. To improve the feasibility and wearability of Vigilance estimation devices for real-world applications, we adopt a novel electrode placement for forehead EOG and extract various eye movement features, which contain the principal information of traditional EOG. We explore the effects of EEG from different brain areas and combine EEG and forehead EOG to leverage their complementary characteristics for Vigilance estimation. Considering that the Vigilance of users is a dynamic changing process because the intrinsic mental states of users involve temporal evolution, we introduce continuous conditional neural field and continuous conditional random field models to capture dynamic temporal dependency. MAIN RESULTS:We propose a multimodal approach to estimating Vigilance by combining EEG and forehead EOG and incorporating the temporal dependency of Vigilance into model training. The experimental results demonstrate that modality fusion can improve the performance compared with a single modality, EOG and EEG contain complementary information for Vigilance estimation, and the temporal dependency-based models can enhance the performance of Vigilance estimation. From the experimental results, we observe that theta and alpha frequency activities are increased, while gamma frequency activities are decreased in drowsy states in contrast to awake states. SIGNIFICANCE:The forehead setup allows for the simultaneous collection of EEG and EOG and achieves comparative performance using only four shared electrodes in comparison with the temporal and posterior sites.
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a multimodal approach to estimating Vigilance using eeg and forehead eog
arXiv: Human-Computer Interaction, 2016Co-Authors: Weilong Zheng, Baoliang LuAbstract:Objective. Covert aspects of ongoing user mental states provide key context information for user-aware human computer interactions. In this paper, we focus on the problem of estimating the Vigilance of users using EEG and EOG signals. Approach. To improve the feasibility and wearability of Vigilance estimation devices for real-world applications, we adopt a novel electrode placement for forehead EOG and extract various eye movement features, which contain the principal information of traditional EOG. We explore the effects of EEG from different brain areas and combine EEG and forehead EOG to leverage their complementary characteristics for Vigilance estimation. Considering that the Vigilance of users is a dynamic changing process because the intrinsic mental states of users involve temporal evolution, we introduce continuous conditional neural field and continuous conditional random field models to capture dynamic temporal dependency. Main results. We propose a multimodal approach to estimating Vigilance by combining EEG and forehead EOG and incorporating the temporal dependency of Vigilance into model training. The experimental results demonstrate that modality fusion can improve the performance compared with a single modality, EOG and EEG contain complementary information for Vigilance estimation, and the temporal dependency-based models can enhance the performance of Vigilance estimation. From the experimental results, we observe that theta and alpha frequency activities are increased, while gamma frequency activities are decreased in drowsy states in contrast to awake states. Significance. The forehead setup allows for the simultaneous collection of EEG and EOG and achieves comparative performance using only four shared electrodes in comparison with the temporal and posterior sites.
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off line and on line Vigilance estimation based on linear dynamical system and manifold learning
International Conference of the IEEE Engineering in Medicine and Biology Society, 2010Co-Authors: Baoliang LuAbstract:For many human machine interaction systems, to ensure work safety, the techniques for continuously estimating the Vigilance of operators are highly desirable. Up to now, various methods based on electroencephalogram (EEG) are proposed to solve this problem. However, most of them are static methods and are based on supervised learning strategy. The main deficiencies of the existing methods are that the label information is hard to get and the time dependency of Vigilance changes are ignored. In this paper, we introduce the dynamic characteristics of Vigilance changes into Vigilance estimation and propose a novel model based on linear dynamical system and manifold learning techniques to implement off-line and online Vigilance estimation. In this model, both spatial information of EEG and temporal information of Vigilance changes are used. The label information what we need is merely to know which EEG indices are important for Vigilance estimation. Experimental results show that the mean off-line and on-line correlation coefficients between estimated Vigilance level and local error rate in second-scale without being averaged are 0.89 and 0.83, respectively.
Anne W. Goldizen - One of the best experts on this subject based on the ideXlab platform.
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Short-term behavioural responses of impalas in simulated antipredator and social contexts
PLoS ONE, 2013Co-Authors: François-rené Favreau, Anne W. Goldizen, Olivier Pays, Hervé FritzAbstract:Prey animals often have to trade off foraging against Vigilance. However, Vigilance is costly and individuals are expected to adjust their Vigilance and its cost in relation to social cues and their predation risk. To test this, we conducted playback experiments in the field to study how lions' (Panthera leo) roars and male impalas' (Aepyceros melampus) territorial vocalizations affected the Vigilance and foraging behaviours as well as movements of female impalas. Our results show that impalas adjusted their activities in different ways depending on the vocalizations broadcast. After lions' roars were played, female impalas increased their Vigilance activity (in particular increasing their high-cost Vigilance--Vigilance without chewing), decreased their bite rates and increased their movements, whereas male impalas' vocalizations caused females to decrease their Vigilance (decreasing their low-cost Vigilance--Vigilance while chewing) and increase their movements without affecting their bite rates. Therefore, it appears that predators' vocalizations stimulate anti-predator behaviours such as Vigilance and movement at the expense of foraging, whereas males' vocalizations increase individuals' displacements at the expense of Vigilance. Overall, this study shows that both predator and social cues have direct effects on the behaviour of gregarious prey and need to be considered in future studies.
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Interactions among social monitoring, anti-predator Vigilance and group size in eastern grey kangaroos
Proceedings of the Royal Society B: Biological Sciences, 2010Co-Authors: François-rené Favreau, Anne W. Goldizen, Olivier PaysAbstract:Group size is known to affect both the amount of time that prey animals spend in Vigilance and the degree to which the Vigilance of group members is synchronized. However, the variation in group-size effects reported in the literature is not yet understood. Prey animals exhibit Vigilance both to protect themselves against predators and to monitor other group members, and both forms of Vigilance presumably influence group-size effects on Vigilance. However, our understanding of the patterns of individual investment underlying the time sharing between anti-predator and social Vigilance is still limited. We studied patterns of variation in individual Vigilance and the synchronization of Vigilance with group size in a wild population of eastern grey kangaroos (Macropus giganteus) subject to predation, in particular focusing on peripheral females because we expected that they would exhibit both social and anti-predator Vigilance. There was no global effect of group size on individual Vigilance. The lack of group-size effect was the result of two compensating effects. The proportion of time individuals spent looking at other group members increased, whereas the proportion of time they spent scanning the environment decreased with group size; as a result, overall Vigilance levels did not change with group size. Moreover, a degree of synchrony of Vigilance occurred within groups and that degree increased with the proportion of Vigilance time peripheral females spent in anti-predator Vigilance. Our results highlight the crucial roles of both social and anti-predator components of Vigilance in the understanding of the relationship between group size and Vigilance, as well as in the synchronization of Vigilance among group members.
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The effect of social facilitation on Vigilance in the eastern gray kangaroo, Macropus giganteus.
Behavioral Ecology Behavioural Ecology, 2009Co-Authors: Olivier Pays, Michel Goulard, Etienne Sirot, Anne W. Goldizen, Simon P. Blomberg, Peter J. JarmanAbstract:The relevance of Vigilance activity to predator detection has been demonstrated in numerous studies. However, few studies have investigated the effect of one group member being vigilant on the probability of others being vigilant in group-forming prey species. Thus, we studied Vigilance activity of eastern gray kangaroos Macropus giganteus that still experience occasional predation. We video recorded the behavior of all group members simultaneously and investigated the probability of a focal group member being vigilant (or nonvigilant) in relation to other individuals' vigilant and nonvigilant behaviors. Our results show that the decision of an individual to exhibit a vigilant posture depended on what it and other group members had been doing (scanning or foraging) at the preceding second and on group size. The probability of an individual being vigilant was positively affected by the proportion of companions that were vigilant at the previous second, confirming the existence in this species of a tendency for synchronization of individual Vigilance. Group size affected individuals' Vigilance in 3 ways. First, individuals were more likely to be vigilant if the proportion of their group mates that was vigilant was high, and this was strengthened with increasing group size. Second, the effect of the individual's own Vigilance state (vigilant or not) at the previous second also increased with group size. Third, the probability of an individual being vigilant decreased with group size. These findings increase our understanding of the much-studied relationship between Vigilance and group size. Key words: allelomimesis, group size, kangaroos, neighbor effect, probability of being vigilant, social facilitation, Vigilance.
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Individual variation in the relationship between Vigilance and group size in eastern grey kangaroos
Behavioral Ecology and Sociobiology, 2009Co-Authors: Alecia Carter, Olivier Pays, Anne W. GoldizenAbstract:The mean Vigilance of animals in a group often decreases as their group size increases, yet nothing is known about whether there is individual variability in this relationship in species that change group sizes frequently, such as those that exhibit fission–fusion social systems. We investigated variability in the relationship between group size and Vigilance in the eastern grey kangaroo (Macropus giganteus) by testing whether all individuals showed decreased Vigilance with increased group size, as has been commonly assumed. We carried out both behavioural observations of entire groups of kangaroos and focal observations of individually recognised wild female kangaroos. As in other studies, we found a collective group-size effect on Vigilance; however, individuals varied in their Vigilance patterns. The majority (57%) of the identified individual kangaroos did not show significant group-size effects for any of the recorded measures of Vigilance. The females that did not show a negative group-size effect were, on average, more vigilant than those females that did show a group-size effect, but this difference was not significant. We propose that some females exhibit higher levels of social Vigilance than others, and that this social Vigilance increases with group size, cancelling out any group-size effect on anti-predator Vigilance for those females. Our results therefore suggest that only some prey individuals may gain anti-predator benefits by reducing their time spent scanning when in larger groups. The large amount of variation that we found in the Vigilance behaviour of individual kangaroos highlights the importance of collecting and analysing Vigilance data at the individual level, which requires individual recognition.
Chi Wah Wong - One of the best experts on this subject based on the ideXlab platform.
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template based prediction of Vigilance fluctuations in resting state fmri
NeuroImage, 2018Co-Authors: Maryam Falahpour, Catie Chang, Chi Wah WongAbstract:Abstract Changes in Vigilance or alertness during a typical resting state fMRI scan are inevitable and have been found to affect measures of functional brain connectivity. Since it is not often feasible to monitor Vigilance with EEG during fMRI scans, it would be of great value to have methods for estimating Vigilance levels from fMRI data alone. A recent study, conducted in macaque monkeys, proposed a template-based approach for fMRI-based estimation of Vigilance fluctuations. Here, we use simultaneously acquired EEG/fMRI data to investigate whether the same template-based approach can be employed to estimate Vigilance fluctuations of awake humans across different resting-state conditions. We first demonstrate that the spatial pattern of correlations between EEG-defined Vigilance and fMRI in our data is consistent with the previous literature. Notably, however, we observed a significant difference between the eyes-closed (EC) and eyes-open (EO) conditions, finding stronger negative correlations with Vigilance in regions forming the default mode network and higher positive correlations in thalamus and insula in the EC condition when compared to the EO condition. Taking these correlation maps as “templates” for Vigilance estimation, we found that the template-based approach produced fMRI-based Vigilance estimates that were significantly correlated with EEG-based Vigilance measures, indicating its generalizability from macaques to humans. We also demonstrate that the performance of this method was related to the overall amount of variability in a subject's Vigilance state, and that the template-based approach outperformed the use of the global signal as a Vigilance estimator. In addition, we show that the template-based approach can be used to estimate the variability across scans in the amplitude of the Vigilance fluctuations. We discuss the benefits and tradeoffs of using the template-based approach in future fMRI studies.
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differences in the resting state fmri global signal amplitude between the eyes open and eyes closed states are related to changes in eeg Vigilance
NeuroImage, 2016Co-Authors: Chi Wah Wong, Pamela N DeyoungAbstract:In resting-state functional connectivity magnetic resonance imaging (fcMRI) studies, measures of functional connectivity are often calculated after the removal of a global mean signal component. While the application of the global signal regression approach has been shown to reduce the influence of physiological artifacts and enhance the detection of functional networks, there is considerable controversy regarding its use as the method can lead to significant bias in the resultant connectivity measures. In addition, evidence from recent studies suggests that the global signal is linked to neural activity and may carry clinically relevant information. For instance, in a prior study we found that the amplitude of the global signal was negatively correlated with EEG measures of Vigilance across subjects and experimental runs. Furthermore, caffeine-related decreases in global signal amplitude were associated with increases in EEG Vigilance. In this study, we extend the prior work by examining measures of global signal amplitude and EEG Vigilance under eyes-closed (EC) and eyes-open (EO) resting-state conditions. We show that changes (EO minus EC) in the global signal amplitude are negatively correlated with the associated changes in EEG Vigilance. The slope of this EO-EC relation is comparable with the slope of the previously reported relation between caffeine-related changes in the global signal amplitude and EEG Vigilance. Our findings provide further support for a basic relationship between global signal amplitude and EEG Vigilance.
Weilong Zheng - One of the best experts on this subject based on the ideXlab platform.
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a multimodal approach to estimating Vigilance using eeg and forehead eog
Journal of Neural Engineering, 2017Co-Authors: Weilong Zheng, Baoliang LuAbstract:OBJECTIVE:Covert aspects of ongoing user mental states provide key context information for user-aware human computer interactions. In this paper, we focus on the problem of estimating the Vigilance of users using EEG and EOG signals. APPROACH:The PERCLOS index as Vigilance annotation is obtained from eye tracking glasses. To improve the feasibility and wearability of Vigilance estimation devices for real-world applications, we adopt a novel electrode placement for forehead EOG and extract various eye movement features, which contain the principal information of traditional EOG. We explore the effects of EEG from different brain areas and combine EEG and forehead EOG to leverage their complementary characteristics for Vigilance estimation. Considering that the Vigilance of users is a dynamic changing process because the intrinsic mental states of users involve temporal evolution, we introduce continuous conditional neural field and continuous conditional random field models to capture dynamic temporal dependency. MAIN RESULTS:We propose a multimodal approach to estimating Vigilance by combining EEG and forehead EOG and incorporating the temporal dependency of Vigilance into model training. The experimental results demonstrate that modality fusion can improve the performance compared with a single modality, EOG and EEG contain complementary information for Vigilance estimation, and the temporal dependency-based models can enhance the performance of Vigilance estimation. From the experimental results, we observe that theta and alpha frequency activities are increased, while gamma frequency activities are decreased in drowsy states in contrast to awake states. SIGNIFICANCE:The forehead setup allows for the simultaneous collection of EEG and EOG and achieves comparative performance using only four shared electrodes in comparison with the temporal and posterior sites.
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a multimodal approach to estimating Vigilance using eeg and forehead eog
arXiv: Human-Computer Interaction, 2016Co-Authors: Weilong Zheng, Baoliang LuAbstract:Objective. Covert aspects of ongoing user mental states provide key context information for user-aware human computer interactions. In this paper, we focus on the problem of estimating the Vigilance of users using EEG and EOG signals. Approach. To improve the feasibility and wearability of Vigilance estimation devices for real-world applications, we adopt a novel electrode placement for forehead EOG and extract various eye movement features, which contain the principal information of traditional EOG. We explore the effects of EEG from different brain areas and combine EEG and forehead EOG to leverage their complementary characteristics for Vigilance estimation. Considering that the Vigilance of users is a dynamic changing process because the intrinsic mental states of users involve temporal evolution, we introduce continuous conditional neural field and continuous conditional random field models to capture dynamic temporal dependency. Main results. We propose a multimodal approach to estimating Vigilance by combining EEG and forehead EOG and incorporating the temporal dependency of Vigilance into model training. The experimental results demonstrate that modality fusion can improve the performance compared with a single modality, EOG and EEG contain complementary information for Vigilance estimation, and the temporal dependency-based models can enhance the performance of Vigilance estimation. From the experimental results, we observe that theta and alpha frequency activities are increased, while gamma frequency activities are decreased in drowsy states in contrast to awake states. Significance. The forehead setup allows for the simultaneous collection of EEG and EOG and achieves comparative performance using only four shared electrodes in comparison with the temporal and posterior sites.
Joel S Warm - One of the best experts on this subject based on the ideXlab platform.
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A Multivariate Test Battery for Predicting Vigilance
Proceedings of the Human Factors and Ergonomics Society Annual Meeting, 2010Co-Authors: Gerald Matthews, Joel S Warm, Tyler H. Shaw, Victor FinomoreAbstract:It has proved difficult to predict individual differences in Vigilance from standard psychometric tests. We report a study that explored the utility of a multivariate battery in predicting Vigilance on a task requiring monitoring of a tactical display. A two-phase design was employed. Participants performed a short Vigilance task (SVT) prior to the longer criterion monitoring task. We investigated the predictive ability of cognitive ability, personality, performance on the SVT, and stress responses to the SVT. Four versions of the criterion task were used, to test generalization of predictive validity. Key predictors of Vigilance were found to include ability, SVT performance, and subjective task engagement and coping. Multiple regression analyses suggested that together these predictors explained about 30% of the variance in Vigilance (with some differences for prediction of different task versions). Results are discussed in relation to the resource theory of Vigilance, and the practical issues arising f...
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individual differences in Vigilance personality ability and states of stress
Journal of Research in Personality, 2010Co-Authors: Tyler H. Shaw, Joel S Warm, Gerald Matthews, Victor Finomore, Leanne Silverman, Paul T CostaAbstract:Abstract Vigilance is notoriously hard to predict from personality measures. This study adopted a new multivariate approach based on attentional resource theory. Measures were taken of the Five Factor Model (FFM), more narrowly-defined ‘cognitive–energetic’ traits, cognitive ability and stress and coping scales. Participants (210) performed one of two related high-workload visual Vigilance tasks. Results showed that personality traits were weak predictors of correct detection rate, although extraversion was negatively correlated with performance. Ability, subjective task engagement and coping scales were more strongly associated with Vigilance. However, both the FFM and cognitive–energetic factors related to subjective states experienced during performance. Data support multivariate approaches to the prediction of Vigilance based on attentional resource theory.
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cerebral hemodynamics and Vigilance performance
Military Psychology, 2009Co-Authors: Joel S Warm, Gerald Matthews, Raja ParasuramanAbstract:Five studies are described using transcranial Doppler sonography (TCD) and near-infrared spectroscopy (NIRS) to examine brain systems in Vigilance. The results indicate that the Vigilance decrement, the temporal decline that typifies Vigilance performance, is paralleled by a decline in cerebral blood flow velocity as indexed by TCD. In addition, both measures showed greater activity in the right than in the left cerebral hemisphere in response to a variety of psychophysical challenges, indicating a right hemispheric system in control of Vigilance performance. The TCD measure was also found to be potentially useful in selecting observers for Vigilance assignments.
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signal salience and the mindlessness theory of Vigilance
Acta Psychologica, 2008Co-Authors: William S. Helton, Joel S WarmAbstract:The present study was designed to explore whether sustained attention tasks can be adequately described by a mindlessness perspective or a limited resource perspective. One hundred and seventy six participants (88 women and 88 men) were assigned at random to one of two signal salience conditions: high and low. Performance and self-reported states, Energetic Arousal, Tense Arousal, Task-Related-Thoughts, and Task-Unrelated-Thoughts, were collected. Overall performance efficiency and the rate of the Vigilance decrement were influenced by the salience level of the signal being observed. Post-task self-reports of Task-Unrelated-Thoughts were significantly related to overall performance efficiency, but not with the Vigilance decrement. Post-task self-reports of Energetic Arousal were significantly related to both overall performance and the Vigilance decrement. The results support a resource theory perspective in regards to the Vigilance decrement and are in contradiction to the mindlessness theory in regards to the Vigilance decrement.
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Vigilance requires hard mental work and is stressful
Human Factors, 2008Co-Authors: Joel S Warm, Raja Parasuraman, Gerald MatthewsAbstract:Objective: We describe major discoveries and developments in Vigilance research. Background: Vigilance tasks have typically been viewed as undemanding assignments requiring little mental effort. The Vigilance decrement function has also been considered to result from a decline in arousal brought about by understimulation. Methods: Recent research in Vigilance is reviewed in four areas: studies of task type, perceived mental workload during Vigilance, neural measures of resource demand in Vigilance, and studies of task-induced stress. Results: Experiments comparing successive and simultaneous Vigilance tasks support an attentional resource theory of Vigilance. Subjective reports also show that the workload of Vigilance is high and sensitive to factors that increase processing demands. Neuroimaging studies using transcranial Doppler sonography provide strong, independent evidence for resource changes linked to performance decrement in Vigilance tasks. Finally, physiological and subjective reports confirm th...
