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Sample records for rat-psychomotor vigilance task

  1. Sleep Deprivation and Time-on-Task Performance Decrement in the Rat Psychomotor Vigilance Task

    PubMed Central

    Oonk, Marcella; Davis, Christopher J.; Krueger, James M.; Wisor, Jonathan P.; Van Dongen, Hans P.A.

    2015-01-01

    Study Objectives: The rat psychomotor vigilance task (rPVT) was developed as a rodent analog of the human psychomotor vigilance task (hPVT). We examined whether rPVT performance displays time-on-task effects similar to those observed on the hPVT. Design: The rPVT requires rats to respond to a randomly presented light stimulus to obtain a water reward. Rats were water deprived for 22 h prior to each 30-min rPVT session to motivate performance. We analyzed rPVT performance over time on task and as a function of the response-stimulus interval, at baseline and after sleep deprivation. Setting: The study was conducted in an academic research vivarium. Participants: Male Long-Evans rats were trained to respond to a 0.5 sec stimulus light within 3 sec of stimulus onset. Complete data were available for n = 20 rats. Interventions: Rats performed the rPVT for 30 min at baseline and after 24 h total sleep deprivation by gentle handling. Measurements and Results: Compared to baseline, sleep deprived rats displayed increased performance lapses and premature responses, similar to hPVT lapses of attention and false starts. However, in contrast to hPVT performance, the time-on-task performance decrement was not significantly enhanced by sleep deprivation. Moreover, following sleep deprivation, rPVT response times were not consistently increased after short response-stimulus intervals. Conclusions: The rat psychomotor vigilance task manifests similarities to the human psychomotor vigilance task in global performance outcomes, but not in post-sleep deprivation effects of time on task and response-stimulus interval. Citation: Oonk M, Davis CJ, Krueger JM, Wisor JP, Van Dongen HPA. Sleep deprivation and time-on-task performance decrement in the rat psychomotor vigilance task. SLEEP 2015;38(3):445–451. PMID:25515099

  2. Discriminating between Hyperactive and Control Preschoolers: The Preschool Vigilance Task.

    ERIC Educational Resources Information Center

    Harper, Gary W.; And Others

    This study examined the ability of a newly developed computerized visual vigilance measure, the Preschool Vigilance Task (PVT), to differentiate between 20 hyperactive and 20 control preschoolers. The PVT was developed to minimize cognitive requirements in a vigilance measure. The study compared performance of the subjects on the PVT and the…

  3. Biocybernetic Control of Vigilance Task Parameters

    NASA Technical Reports Server (NTRS)

    Freeman, Frederick G.

    2000-01-01

    The major focus of the present proposal was to examine psychophysiological variables that are related to hazardous states of awareness induced by monitoring automated systems. With the increased use of automation in today's work environment, people's roles in the work place are being redefined from that of active participant to one of passive monitor. Although the introduction of automated systems has a number of benefits, there are also a number of disadvantages regarding the worker performance. Byrne and Parasuraman (1996) have argued for the use of psychophysiological measures in both the development and the implementation of adaptive automation. While both performance based and model based adaptive automation have been studied, the use of psychophysiological measures, especially EEG, offers the advantage of real time evaluation of the state of the subject. Previous investigations of the closed-loop adaptive automation system in our laboratory, supported by NASA, have employed a compensatory tracking task which involved the use of a joystick to maintain the position of a cursor in the middle of a video screen. This research demonstrated that, in an adaptive automation, closed-loop environment, subjects perform a tracking task better under a negative, compared to a positive, feedback condition. While tracking is comparable to some aspects of flying an airplane, it does not simulate the environment found in the cockpit of modern commercial airplanes. Since a large part of the flying responsibilities in commercial airplanes is automated, the primary responsibility of pilots is to monitor the automation and to respond when the automation fails. Because failures are relatively rare, pilots often suffer from hazardous states of awareness induced by long term vigilance of the automated system. Consequently, the aim of the current study was to investigate the ability of the closed-loop, adaptive automation system in a vigilance paradigm. It is also important to note

  4. Physiological Synchronization in a Vigilance Dual Task.

    PubMed

    Guastello, Stephen J

    2016-01-01

    The synchronization of autonomic arousal levels and other physio-logical responses between people is a potentially important component of work team performance, client-therapist relationships, and other types of human interaction. This study addressed several problems: What statistical models are viable for identifying synchronization for loosely coupled human systems? How is the level of synchronization related to psychosocial variables such as empathy, subjective ratings of workload, and actual performance? Participants were 70 undergraduates who worked in pairs on a vigilance dual task in which they watched a virtual reality security camera, rang a bell when they saw the target intruder, and completed a jig-saw puzzle. Event rates either increased or decreased during the 90 min work period. The average R2 values for each person were .66, .66, .62, and .53 for the linear autoregressive model, linear autoregressive model with a synchronization component, the nonlinear autoregressive model, and the nonlinear autoregressive model with a synchronization component, respectively. All models were more accurate at a lag of 20 sec compared to 50 sec or customized lag lengths. Although the linear models were more accurate overall, the nonlinear synchronization parameters were more often related to psychological variables and performance. In particular, greater synchronization was observed with the nonlinear model when the target event rate increased, compared to when it decreased, which was expected from the general theory of synchronization. Nonlinear models were also more effective for uncovering inhibitory or dampening relationships between the co-workers as well as mutually excitatory relationships. Future research should explore the comparative model results for tasks that induce higher levels of synchronization and involve different types of internal group coordination. PMID:26639921

  5. Influence of gender on psychomotor vigilance task performance by adolescents.

    PubMed

    Beijamini, F; Silva, A G T; Peixoto, C A T; Louzada, F M

    2008-08-01

    During adolescence, the sleep phase delay associated with early school times increases daytime sleepiness and reduces psychomotor performance. Some studies have shown an effect of gender on psychomotor performance in adults and children. Males present faster reaction times (RT) compared with females. The aim of the present study was to evaluate the influence of gender on Palm psychomotor vigilance task (PVT) performance in adolescents. Thirty-four adolescents (19 girls, 13 to 16 years old) attending morning school classes of a public school in Curitiba, PR, Brazil, participated in the study. Sleep patterns were measured using actigraphy and sleepiness data were accessed with the Karolinska Sleepiness Scale (KSS). KSS and PVT measurements were collected at two times in the morning (8:00 and 11:00 h). The data were compared using one-way ANOVA, considering gender as a factor. ANOVA indicated that gender did not affect sleep patterns and subjective somnolence; however, a statistically significant effect of gender was detected for PVT performance. Boys presented faster RT (RT-PVT1: 345.51 ms, F = 6.08, P < 0.05; RT-PVT2: 343.30 ms, F = 6.35, P < 0.05) and fewer lapses (lapses-PVT1: 8.71, F = 4.45, P < 0.05; lapses-PVT2: 7.82, F = 7.06, P < 0.05) compared with girls (RT-PVT1: 402.96; RT-PVT2: 415.70; lapses-PVT1: 16.33; lapses-PVT2: 17.80). These results showed that this effect of gender, already reported in adults and children, is also observed in adolescents. The influence of gender should be taken into account in studies that use Palm PVT to evaluate psychomotor performance in this age range. PMID:18797710

  6. Brief and Rare Mental "Breaks" Keep You Focused: Deactivation and Reactivation of Task Goals Preempt Vigilance Decrements

    ERIC Educational Resources Information Center

    Ariga, Atsunori; Lleras, Alejandro

    2011-01-01

    We newly propose that the vigilance decrement occurs because the cognitive control system fails to maintain active the goal of the vigilance task over prolonged periods of time (goal habituation). Further, we hypothesized that momentarily deactivating this goal (via a switch in tasks) would prevent the activation level of the vigilance goal from…

  7. Rest improves performance, nature improves happiness: Assessment of break periods on the abbreviated vigilance task.

    PubMed

    Finkbeiner, Kristin M; Russell, Paul N; Helton, William S

    2016-05-01

    The abbreviated vigilance task can quickly generate vigilance decrements, which has been argued is due to depletion of cognitive resources needed to sustain performance. Researchers suggest inclusion of rest breaks within vigilance tasks improve overall performance (Helton & Russell, 2015; Ross, Russell, & Helton, 2014), while different types of breaks demonstrate different effects. Some literature suggests exposure to natural movements/stimuli helps restore attention (Herzog, Black, Fountaine, & Knotts, 1997; Kaplan, 1995). Participants were randomly assigned to one experimental condition: dog video breaks, robot video breaks, countdown breaks or continuous vigilance. We assessed task performance and subjective reports of stress/workload. The continuous group displayed worst performance, suggesting breaks help restore attention. The dog videos did not affect performance, however, decreased reports of distress. These results support the importance of rest breaks and acknowledge the benefit of natural stimuli for promoting wellbeing/stress relief, overall suggesting performance and wellbeing may be independent, which warrants future studies. PMID:27089530

  8. Examination of vigilance and disengagement of threat in social anxiety with a probe detection task.

    PubMed

    Klumpp, Heide; Amir, Nader

    2009-05-01

    Selective attention for threat faces in social anxiety is commonly measured with a probe detection task. Various studies that have used this task show socially anxious individuals exhibit selective attention for threat faces (Mogg & Bradley, 2002; Mogg, Philippot, & Bradley, 2004b; Pishyar, Harris, & Menzies, 2004). Selective attention for threat when measured with a probe detection task is interpreted as an attentional shift toward threat ("vigilance"). Yet, there is data that show socially anxious individuals may have difficulty in shifting their attention away from threat ("disengagement"; Amir, Elias, Klumpp, & Przeworski, 2003). A step toward clarifying the extent to which selective attention for threat comprises vigilance or disengagement effects is described by Koster, Crombez, Verschuere, and de Houwer (2004). We adapted their modified probe detection task to examine vigilance and disengagement effects for threat and happy faces in individuals with and without social anxiety. The results indicate that socially anxious individuals exhibit vigilance for threat faces, but not for happy faces, compared to individuals without social anxiety. Our study is consistent with cognitive theories of anxiety that propose vigilance for threat may contribute to the maintenance of anxiety disorders. PMID:19253172

  9. Vigilance impossible: Diligence, distraction, and daydreaming all lead to failures in a practical monitoring task.

    PubMed

    Casner, Stephen M; Schooler, Jonathan W

    2015-09-01

    In laboratory studies of vigilance, participants watch for unusual events in a "sit and stare" fashion as their performance typically declines over time. But watch keepers in practical settings seldom approach monitoring in such simplistic ways and controlled environments. We observed airline pilots performing routine monitoring duties in the cockpit. Unlike laboratory studies, pilots' monitoring did not deteriorate amidst prolonged vigils. Monitoring was frequently interrupted by other pop-up tasks and misses followed. However, when free from these distractions, pilots reported copious mind wandering. Pilots often confined their mind wandering to times in which their monitoring performance would not conspicuously suffer. But when no convenient times were available, pilots mind wandered anyway and misses ensued. Real-world monitors may be caught between a continuous vigilance approach that is doomed to fail, a dynamic environment that cannot be fully controlled, and what may be an irresistible urge to let one's thoughts drift. PMID:25966369

  10. Vigilance and task load - In search of the inverted U

    NASA Technical Reports Server (NTRS)

    Wiener, E. L.; Curry, R. E.; Faustina, M. L.

    1984-01-01

    The 'Inverted-U Hypothesis' states that for a given task, there is an optimal level of workload or demand that yields the highest level of performance. A departure in either direction will result in a monotonically lower performance level, hence an inverted-U-shaped relationship between task demand and quality of performance. Most studies to date have failed to demonstrate the left-hand branch of the curve, that is, the regime in which performance presumably rises as load increases. The purpose of this study was to explore whether low-level additional demand on the monitor would result in improved performance. Four groups of subjects performed a visual monitoring task for 48 min, then two of the four groups were given additional tasks, and a third had potentially distracting information on its display. Results indicated that the two groups with additional demand detected more signals than did the control group or the control-plus-distraction group. There were no significant differences in false alarms.

  11. The electrocortical correlates of fluctuating states of attention during vigilance tasks

    NASA Technical Reports Server (NTRS)

    Cunningham, Stephen G.; Freeman, Frederick

    1994-01-01

    This study investigated the electrocortical correlates of attention. Sixteen subjects (seven females, nine males) engaged in a forty-minute target detection vigilance task. Task-irrelevant probe tones were presented every 2-4 seconds. While performing the vigilance task, the subjects were asked to press a button if they were daydreaming (i.e. having a task unrelated thought or TUT). Continuous electroencephalograms (EEG's) and event-related potentials (ERP's) were recorded from the subjects during the entire task. The continuous EEG data were analyzed for differences in absolute power throughout the task as well as before and after the subjects indicated that they were daydreaming (TUT response). ERP's elicited by task-irrelevant probe tones were analyzed in the same manner. The results indicated performance decrements as reflected by increased RT to correct detections, and decreased number of hits. Further, as the task progressed, the number of reports of daydreaming increased. The analysis of the EEG data indicated a significant difference in the absolute power of the different frequency bands across periods. The greatest difference was observed at the posterior parietal electrode sites. In addition, when the EEG data was converted into band ratios (beta/alpha and beta/alpha+theta), the pre-TUT conditions were found to be significantly different than the post-TUT conditions in the posterior sites. The ERP components (N1, N2, and P2) were not significantly different before and after a TUT response or across periods. However, the ERP's across periods exhibited amplitudes that were similar to those found in previous studies of vigilance and ERP's.

  12. Psychomotor Vigilance Task Performance During and Following Chronic Sleep Restriction in Rats

    PubMed Central

    Deurveilher, Samuel; Bush, Jacquelyn E.; Rusak, Benjamin; Eskes, Gail A.; Semba, Kazue

    2015-01-01

    Study Objectives: Chronic sleep restriction (CSR) impairs sustained attention in humans, as commonly assessed with the psychomotor vigilance task (PVT). To further investigate the mechanisms underlying performance deficits during CSR, we examined the effect of CSR on performance on a rat version of PVT (rPVT). Design: Adult male rats were trained on a rPVT that required them to press a bar when they detected irregularly presented, brief light stimuli, and were then tested during CSR. CSR consisted of 100 or 148 h of continuous cycles of 3-h sleep deprivation (using slowly rotating wheels) alternating with a 1-h sleep opportunity (3/1 protocol). Measurements and Results: After 28 h of CSR, the latency of correct responses and the percentages of lapses and omissions increased, whereas the percentage of correct responses decreased. Over 52–148 h of CSR, all performance measures showed partial or nearly complete recovery, and were at baseline levels on the first or second day after CSR. There were large interindividual differences in the magnitude of performance impairment during CSR, suggesting differential vulnerability to the effects of sleep loss. Wheel-running controls showed no changes in performance. Conclusions: A 28-h period of the 3/1 chronic sleep restriction (CSR) protocol disrupted performance on a sustained attention task in rats, as sleep deprivation does in humans. Performance improved after longer periods of CSR, suggesting allostatic adaptation, contrary to some reports of progressive deterioration in psychomotor vigilance task performance during CSR in humans. However, as observed in humans, there were individual differences among rats in the vulnerability of their attention performance to CSR. Citation: Deurveilher S, Bush JE, Rusak B, Eskes GA, Semba K. Psychomotor vigilance task performance during and following chronic sleep restriction in rats. SLEEP 2015;38(4):515–528. PMID:25515100

  13. Investigating the correlation between the neural activity and task performance in a psychomotor vigilance test.

    PubMed

    Hu, Zhongze; Sun, Yu; Lim, Julian; Thakor, Nitish; Bezerianos, Anastasios

    2015-01-01

    Neural activity is known to correlate with decrements in task performance as individuals enter the state of mental fatigue which might lead to lowered productivity and increased safety risks. Incorporating a passive brain computer interface (BCI) technique that detects changes in subject's neural activity and predicts the behavioral performance when the subject is underperforming might be a promising approach to reduce human error in real-world situations. Here, we developed a reliable model using EEG power spectrum to estimate time-on-task performance in a psychomotor vigilance test (PVT) which can fit across individuals. High correlation between the estimated and actual reaction time was achieved. Hence, our results illustrate the feasibility for modeling time-on-task decrements in performance among different individuals from their brainwave activity, with potential applications in several domains, including traffic and industrial safety. PMID:26737349

  14. PC-PVT: a platform for psychomotor vigilance task testing, analysis, and prediction.

    PubMed

    Khitrov, Maxim Y; Laxminarayan, Srinivas; Thorsley, David; Ramakrishnan, Sridhar; Rajaraman, Srinivasan; Wesensten, Nancy J; Reifman, Jaques

    2014-03-01

    Using a personal computer (PC) for simple visual reaction time testing is advantageous because of the relatively low hardware cost, user familiarity, and the relative ease of software development for specific neurobehavioral testing protocols. However, general-purpose computers are not designed with the millisecond-level accuracy of operation required for such applications. Software that does not control for the various sources of delay may return reaction time values that are substantially different from the true reaction times. We have developed and characterized a freely available system for PC-based simple visual reaction time testing that is analogous to the widely used psychomotor vigilance task (PVT). In addition, we have integrated individualized prediction algorithms for near-real-time neurobehavioral performance prediction. We characterized the precision and accuracy with which the system as a whole measures reaction times on a wide range of computer hardware configurations, comparing its performance with that of the "gold standard" PVT-192 device. We showed that the system is capable of measuring reaction times with an average delay of less than 10 ms, a margin of error that is comparable to that of the gold standard. The most critical aspect of hardware selection is the type of mouse used for response detection, with gaming mice showing a significant advantage over standard ones. The software is free to download from http://bhsai.org/downloads/pc-pvt/ . PMID:23709163

  15. Time-on-task decrement in vigilance is modulated by inter-individual vulnerability to homeostatic sleep pressure manipulation.

    PubMed

    Maire, Micheline; Reichert, Carolin F; Gabel, Virginie; Viola, Antoine U; Krebs, Julia; Strobel, Werner; Landolt, Hans-Peter; Bachmann, Valérie; Cajochen, Christian; Schmidt, Christina

    2014-01-01

    Under sleep loss, vigilance is reduced and attentional failures emerge progressively. It becomes difficult to maintain stable performance over time, leading to growing performance variability (i.e., state instability) in an individual and among subjects. Task duration plays a major role in the maintenance of stable vigilance levels, such that the longer the task, the more likely state instability will be observed. Vulnerability to sleep-loss-dependent performance decrements is highly individual and is also modulated by a polymorphism in the human clock gene PERIOD3 (PER3). By combining two different protocols, we manipulated sleep-wake history by once extending wakefulness for 40 h (high sleep pressure condition) and once by imposing a short sleep-wake cycle by alternating 160 min of wakefulness and 80 min naps (low sleep pressure condition) in a within-subject design. We observed that homozygous carriers of the long repeat allele of PER3 (PER3 (5/5) ) experienced a greater time-on-task dependent performance decrement (i.e., a steeper increase in the number of lapses) in the Psychomotor Vigilance Task compared to the carriers of the short repeat allele (PER3 (4/4) ). These genotype-dependent effects disappeared under low sleep pressure conditions, and neither motivation, nor perceived effort accounted for these differences. Our data thus suggest that greater sleep-loss related attentional vulnerability based on the PER3 polymorphism is mirrored by a greater state instability under extended wakefulness in the short compared to the long allele carriers. Our results undermine the importance of time-on-task related aspects when investigating inter-individual differences in sleep loss-induced behavioral vulnerability. PMID:24639634

  16. Sustaining Attention to Simple Tasks: A Meta-Analytic Review of the Neural Mechanisms of Vigilant Attention

    PubMed Central

    Langner, Robert; Eickhoff, Simon B.

    2012-01-01

    Maintaining attention for more than a few seconds is essential for mastering everyday life. Yet, our ability to stay focused on a particular task is limited, resulting in well-known performance decrements with increasing time on task. Intriguingly, such decrements are even more likely if the task is cognitively simple and repetitive. The attentional function that enables our prolonged engagement in intellectually unchallenging, uninteresting activities has been termed “vigilant attention.” Here we synthesized what we have learnt from functional neuroimaging about the mechanisms of this essential mental faculty. To this end, a quantitative meta-analysis of pertinent neuroimaging studies was performed, including supplementary analyses of moderating factors. Furthermore, we reviewed the available evidence on neural time-on-task effects, additionally considering information obtained from patients with focal brain damage. Integrating the results of both meta-analysis and review, a set of mainly right-lateralized brain regions was identified that may form the core network subserving vigilant attention in humans, including dorsomedial, mid- and ventrolateral prefrontal cortex, anterior insula, parietal areas (intraparietal sulcus, temporo-parietal junction), and subcortical structures (cerebellar vermis, thalamus, putamen, midbrain). We discuss the potential functional roles of different nodes of this network as well as implications of our findings for a theoretical account of vigilant attention. It is conjectured that sustaining attention is a multi-component, non-unitary mental faculty, involving a mixture of (i) sustained/recurrent processes subserving task-set/arousal maintenance and (ii) transient processes subserving the target-driven reorienting of attention. Finally, limitations of previous studies are considered and suggestions for future research are provided. PMID:23163491

  17. Reaction Time and Accuracy in Individuals with Aphasia during Auditory Vigilance Tasks

    ERIC Educational Resources Information Center

    Laures, Jacqueline S.

    2005-01-01

    Research indicates that attentional deficits exist in aphasic individuals. However, relatively little is known about auditory vigilance performance in individuals with aphasia. The current study explores reaction time (RT) and accuracy in 10 aphasic participants and 10 nonbrain-damaged controls during linguistic and nonlinguistic auditory…

  18. On the Need of Objective Vigilance Monitoring: Effects of Sleep Loss on Target Detection and Task-Negative Activity Using Combined EEG/fMRI

    PubMed Central

    Czisch, Michael; Wehrle, Renate; Harsay, Helga A.; Wetter, Thomas C.; Holsboer, Florian; Sämann, Philipp G.; Drummond, Sean P. A.

    2012-01-01

    Sleep loss affects attention by reducing levels of arousal and alertness. The neural mechanisms underlying the compensatory efforts of the brain to maintain attention and performance after sleep deprivation (SD) are not fully understood. Previous neuroimaging studies of SD have not been able to separate the effects of reduced arousal from the effects of SD on cerebral responses to cognitive challenges. Here, we used a simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) approach to study the effects of 36 h of total sleep deprivation (TSD). Specifically, we focused on changes in selective attention processes as induced by an active acoustic oddball task, with the ability to isolate runs with objective EEG signs of high (SDalert) or reduced (SDsleepy) vigilance. In the SDalert condition, oddball task-related activity appears to be sustained by compensatory co-activation of insular regions, but task-negative activity in the right posterior node of the default mode network is altered following TSD. In the SDsleepy condition, oddball task-positive activity was massively impaired, but task-negative activation was showing levels comparable with the control condition after a well-rested night. Our results suggest that loss of strict negative correlation between oddball task-positive and task-negative activation reflects the effects of TSD, while the actual state of vigilance during task performance can affects either task-related or task-negative activity, depending on the exact vigilance level. PMID:22557992

  19. On the Need of Objective Vigilance Monitoring: Effects of Sleep Loss on Target Detection and Task-Negative Activity Using Combined EEG/fMRI.

    PubMed

    Czisch, Michael; Wehrle, Renate; Harsay, Helga A; Wetter, Thomas C; Holsboer, Florian; Sämann, Philipp G; Drummond, Sean P A

    2012-01-01

    Sleep loss affects attention by reducing levels of arousal and alertness. The neural mechanisms underlying the compensatory efforts of the brain to maintain attention and performance after sleep deprivation (SD) are not fully understood. Previous neuroimaging studies of SD have not been able to separate the effects of reduced arousal from the effects of SD on cerebral responses to cognitive challenges. Here, we used a simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) approach to study the effects of 36 h of total sleep deprivation (TSD). Specifically, we focused on changes in selective attention processes as induced by an active acoustic oddball task, with the ability to isolate runs with objective EEG signs of high (SD(alert)) or reduced (SD(sleepy)) vigilance. In the SD(alert) condition, oddball task-related activity appears to be sustained by compensatory co-activation of insular regions, but task-negative activity in the right posterior node of the default mode network is altered following TSD. In the SD(sleepy) condition, oddball task-positive activity was massively impaired, but task-negative activation was showing levels comparable with the control condition after a well-rested night. Our results suggest that loss of strict negative correlation between oddball task-positive and task-negative activation reflects the effects of TSD, while the actual state of vigilance during task performance can affects either task-related or task-negative activity, depending on the exact vigilance level. PMID:22557992

  20. Vigilance Task-Related Change in Brain Functional Connectivity as Revealed by Wavelet Phase Coherence Analysis of Near-Infrared Spectroscopy Signals

    PubMed Central

    Wang, Wei; Wang, Bitian; Bu, Lingguo; Xu, Liwei; Li, Zengyong; Fan, Yubo

    2016-01-01

    This study aims to assess the vigilance task-related change in connectivity in healthy adults using wavelet phase coherence (WPCO) analysis of near-infrared spectroscopy signals (NIRS). NIRS is a non-invasive neuroimaging technique for assessing brain activity. Continuous recordings of the NIRS signals were obtained from the prefrontal cortex (PFC) and sensorimotor cortical areas of 20 young healthy adults (24.9 ± 3.3 years) during a 10-min resting state and a 20-min vigilance task state. The vigilance task was used to simulate driving mental load by judging three random numbers (i.e., whether odd numbers). The task was divided into two sessions: the first 10 min (Task t1) and the second 10 min (Task t2). The WPCO of six channel pairs were calculated in five frequency intervals: 0.6–2 Hz (I), 0.145–0.6 Hz (II), 0.052–0.145 Hz (III), 0.021–0.052 Hz (IV), and 0.0095–0.021 Hz (V). The significant WPCO formed global connectivity (GC) maps in intervals I and II and functional connectivity (FC) maps in intervals III to V. Results show that the GC levels in interval I and FC levels in interval III were significantly lower in the Task t2 than in the resting state (p < 0.05), particularly between the left PFC and bilateral sensorimotor regions. Also, the reaction time (RT) shows an increase in Task t2 compared with that in Task t1. However, no significant difference in WPCO was found between Task t1 and resting state. The results showed that the change in FC at the range of 0.6–2 Hz was not attributed to the vigilance task per se, but the interaction effect of vigilance task and time factors. The findings suggest that the decreased attention level might be partly attributed to the reduced GC levels between the left prefrontal region and sensorimotor area. The present results provide a new insight into the vigilance task-related brain activity. PMID:27547182

  1. Vigilance Task-Related Change in Brain Functional Connectivity as Revealed by Wavelet Phase Coherence Analysis of Near-Infrared Spectroscopy Signals.

    PubMed

    Wang, Wei; Wang, Bitian; Bu, Lingguo; Xu, Liwei; Li, Zengyong; Fan, Yubo

    2016-01-01

    This study aims to assess the vigilance task-related change in connectivity in healthy adults using wavelet phase coherence (WPCO) analysis of near-infrared spectroscopy signals (NIRS). NIRS is a non-invasive neuroimaging technique for assessing brain activity. Continuous recordings of the NIRS signals were obtained from the prefrontal cortex (PFC) and sensorimotor cortical areas of 20 young healthy adults (24.9 ± 3.3 years) during a 10-min resting state and a 20-min vigilance task state. The vigilance task was used to simulate driving mental load by judging three random numbers (i.e., whether odd numbers). The task was divided into two sessions: the first 10 min (Task t1) and the second 10 min (Task t2). The WPCO of six channel pairs were calculated in five frequency intervals: 0.6-2 Hz (I), 0.145-0.6 Hz (II), 0.052-0.145 Hz (III), 0.021-0.052 Hz (IV), and 0.0095-0.021 Hz (V). The significant WPCO formed global connectivity (GC) maps in intervals I and II and functional connectivity (FC) maps in intervals III to V. Results show that the GC levels in interval I and FC levels in interval III were significantly lower in the Task t2 than in the resting state (p < 0.05), particularly between the left PFC and bilateral sensorimotor regions. Also, the reaction time (RT) shows an increase in Task t2 compared with that in Task t1. However, no significant difference in WPCO was found between Task t1 and resting state. The results showed that the change in FC at the range of 0.6-2 Hz was not attributed to the vigilance task per se, but the interaction effect of vigilance task and time factors. The findings suggest that the decreased attention level might be partly attributed to the reduced GC levels between the left prefrontal region and sensorimotor area. The present results provide a new insight into the vigilance task-related brain activity. PMID:27547182

  2. Assessing the effects of caffeine and theanine on the maintenance of vigilance during a sustained attention task.

    PubMed

    Foxe, John J; Morie, Kristen P; Laud, Peter J; Rowson, Matthew J; de Bruin, Eveline A; Kelly, Simon P

    2012-06-01

    Caffeine and L-theanine, both naturally occurring in tea, affect the ability to make rapid phasic deployments of attention to locations in space as reflected in behavioural performance and alpha-band oscillatory brain activity (8-14 Hz). However, surprisingly little is known about how these compounds affect an aspect of attention that has been more popularly associated with tea, namely vigilant attention: the ability to maintain focus on monotonous tasks over protracted time-periods. Twenty-seven participants performed the Sustained Attention to Response Task (SART) over a two-hour session on each of four days, on which they were administered caffeine (50 mg), theanine (100 mg), the combination, or placebo in a double-blind, randomized, cross-over fashion. Concurrently, we recorded oscillatory brain activity through high-density electroencephalography (EEG). We asked whether either compound alone, or both in combination, would affect performance of the task in terms of reduced error rates over time, and whether changes in alpha-band activity would show a relationship to such changes in performance. When treated with placebo, participants showed a rise in error rates, a pattern that is commonly observed with increasing time-on-task, whereas after caffeine and theanine ingestion, error rates were significantly reduced. The combined treatment did not confer any additional benefits over either compound alone, suggesting that the individual compounds may confer maximal benefits at the dosages employed. Alpha-band oscillatory activity was significantly reduced on ingestion of caffeine, particularly in the first hour. This effect was not changed by addition of theanine in the combined treatment. Theanine alone did not affect alpha-band activity. PMID:22326943

  3. Central additive effect of Ginkgo biloba and Rhodiola rosea on psychomotor vigilance task and short-term working memory accuracy

    PubMed Central

    Al-Kuraishy, Hayder M.

    2016-01-01

    Aim: The present study investigates the effect of combined treatment with Ginkgo biloba and/or Rhodiola rosea on psychomotor vigilance task (PVT) and short-term working memory accuracy. Subjects and Methods: A total number of 112 volunteers were enrolled to study the effect of G. biloba and R. rosea on PVT and short-term working memory accuracy as compared to placebo effects, the central cognitive effect was assessed by critical flicker-fusion frequency, PVT, and computerized N-back test. Results: Placebo produced no significant effects on all neurocognitive tests measure P > 0.05 in normal healthy volunteers, G. biloba or R. rosea improve PVT and low to moderate working memory accuracy, The combined effect of R. rosea and G. biloba leading to more significant effect on PVT, all levels of short-term working memory accuracy and critical fusion versus flicker P < 0.01, more than of G. biloba or R. rosea when they used alone. Conclusion: The combined effect of R. rosea and G. biloba leading to a more significant effect on cognitive function than either G. biloba or R. rosea when they used alone. PMID:27069717

  4. Age and Individual Differences in Prospective Memory during a “Virtual Week”: The Roles of Working Memory, Vigilance, Task Regularity, and Cue Focality

    PubMed Central

    Rose, Nathan S.; Rendell, Peter G.; McDaniel, Mark A.; Aberle, Ingo; Kliegel, Matthias

    2011-01-01

    Young (ages 18-22) and older (ages 61-87) adults (N=106) played the Virtual Week board game, which involves simulating common prospective memory (PM) tasks of everyday life (e.g., taking medication), and performed working memory (WM) and vigilance tasks. The Virtual Week game includes regular (repeated) and irregular (non-repeated) PM tasks with cues that are either more or less focal to other ongoing activities. Age differences in PM were reduced for repeated tasks and performance improved over the course of the week, suggesting retrieval was more spontaneous or habitual. Correlations with WM within each age group were reduced for PM tasks that had more regular or focal cues. WM (but not vigilance) ability was a strong predictor of irregular PM tasks with less focal cues. Taken together, these results support the hypothesis that habitual and focally-cued PM tasks are less demanding of attentional “resources” (specifically, WM), whereas tasks that are more demanding of controlled attentional processes produce larger age differences, which may be attributable to individual differences in WM. PMID:20853967

  5. In-flight sleep, pilot fatigue and Psychomotor Vigilance Task performance on ultra-long range versus long range flights.

    PubMed

    Gander, Philippa H; Signal, T Leigh; van den Berg, Margo J; Mulrine, Hannah M; Jay, Sarah M; Jim Mangie, Captain

    2013-12-01

    This study evaluated whether pilot fatigue was greater on ultra-long range (ULR) trips (flights >16 h on 10% of trips in a 90-day period) than on long range (LR) trips. The within-subjects design controlled for crew complement, pattern of in-flight breaks, flight direction and departure time. Thirty male Captains (mean age = 54.5 years) and 40 male First officers (mean age = 48.0 years) were monitored on commercial passenger flights (Boeing 777 aircraft). Sleep was monitored (actigraphy, duty/sleep diaries) from 3 days before the first study trip to 3 days after the second study trip. Karolinska Sleepiness Scale, Samn-Perelli fatigue ratings and a 5-min Psychomotor Vigilance Task were completed before, during and after every flight. Total sleep in the 24 h before outbound flights and before inbound flights after 2-day layovers was comparable for ULR and LR flights. All pilots slept on all flights. For each additional hour of flight time, they obtained an estimated additional 12.3 min of sleep. Estimated mean total sleep was longer on ULR flights (3 h 53 min) than LR flights (3 h 15 min; P(F) = 0.0004). Sleepiness ratings were lower and mean reaction speed was faster at the end of ULR flights. Findings suggest that additional in-flight sleep mitigated fatigue effectively on longer flights. Further research is needed to clarify the contributions to fatigue of in-flight sleep versus time awake at top of descent. The study design was limited to eastward outbound flights with two Captains and two First Officers. Caution must be exercised when extrapolating to different operations. PMID:23889686

  6. Vigilance in a dynamic environment.

    PubMed

    Stearman, Eric J; Durso, Francis T

    2016-03-01

    Advances in technology have led to increasing levels of automation in modern work environments, moving people to the position of a passive monitor. When persons are in passive monitoring states, they are often subject to overall deficits in performance that become worse as time on task increases (i.e., vigilance decrements). Although many factors have been shown to influence whether or not a vigilance decrement will occur in a monitoring task (e.g., event rate), it is not clear how laboratory experiments translate to operational environments (Hancock, 2013). Four experiments were conducted that examined the effects of signal rate, event rate, cognitive load, training, and the presence of a dual task on performance during an air traffic control (ATC) automation failure detection task. Both failure detection and detection time were analyzed. Results from a meta-analysis revealed that cognitive load placed on participants through the use of task-relevant complex instructions produced a reliable vigilance decrement. However, other types of cognitive load did not produce any reliable vigilance decrements. The relationship of the cognitive load to the vigilance task may be an important factor in determining if the cognitive load will produce a vigilance decrement in a dynamic operational environment like air traffic control. (PsycINFO Database Record PMID:26844367

  7. Cognitive Workload and Fatigue in a Vigilance Dual Task: Miss Errors, False Alarms, and the Effect of Wearing Biometric Sensors While Working.

    PubMed

    Guastello, Stephen J; Reiter, Katherine E; Malon, Matthew

    2016-10-01

    The effects of workload, fatigue, and practice on the performance of cognitive tasks are often intertwined. Previous research has shown that these influences can be separated with the two cusp catastrophe models. This study expanded an earlier investigation of the two models for workload and fatigue in a vigilance task to include a wider range of bifurcation variables that could affect the elasticity versus rigidity of the operator in response to workload and added performance variability resulting from fatigue. The study also responded to a concern in the literature that performance on cognitive tasks can be complicated by adaptive responses to artificial task situations and thus distort underlying cognitive events. Therefore, we also explored whether wearing biometric sensors, frequently used in workload studies, can affect performance dynamics. Participants were 279 undergraduates who responded to target stimuli that appeared on a simulated security camera display at three rates of speed while completing a secondary task. Participants worked alone, in pairs, or in pairs wearing GSR sensors. Results supported the efficacy of the two models and isolated the impact of wearing sensors on the fatigue process. The strongest control variables across both the workload and fatigue models were field independence, anxiety, indecisiveness, inflexibility, secondary task completion, working in pairs, and wearing the sensors. The contributing effect of wearing sensors could possibly extend to other types of wearable technologies. PMID:27550706

  8. Neurobehavioral Effects of Space Radiation on Psychomotor Vigilance Tests

    NASA Astrophysics Data System (ADS)

    Hienz, Robert; Davis, Catherine; Weed, Michael; Guida, Peter; Gooden, Virginia; Brady, Joseph; Roma, Peter

    Neurobehavioral Effects of Space Radiation on Psychomotor Vigilance Tests INTRODUCTION Risk assessment of the biological consequences of living in the space radiation environment represents one of the highest priority areas of NASA radiation research. Of critical importance is the need for a risk assessment of damage to the central nervous system (CNS) leading to functional cognitive/behavioral changes during long-term space missions, and the development of effective shielding or biological countermeasures to such risks. The present research focuses on the use of an animal model that employs neurobehavioral tests identical or homologous to those currently in use in human models of risk assessment by U.S. agencies such as the Depart-ment of Defense and Federal Aviation and Federal Railroad Administrations for monitoring performance and estimating accident risks associated with such variables as fatigue and/or alcohol or drug abuse. As a first approximation for establishing human risk assessments due to exposure to space radiation, the present work provides animal performance data obtained with the rPVT (rat Psychomotor Vigilance Test), an animal analog of the human PVT that is currently employed for human risk assessments via quantification of sustained attention (e.g., 'vigilance' or 'readiness to perform' tasks). Ground-based studies indicate that radiation can induce neurobehavioral changes in rodents, including impaired performance on motor tasks and deficits in spatial learning and memory. The present study is testing the hypothesis that radiation exposure impairs motor function, performance accuracy, vigilance, motivation, and memory in adult male rats. METHODS The psychomotor vigilance test (PVT) was originally developed as a human cognitive neurobe-havioral assay for tracking the temporally dynamic changes in sustained attention, and has also been used to track changes in circadian rhythm. In humans the test requires responding to a small, bright

  9. The use of music with young children to improve sustained attention during a vigilance task in the presence of auditory distractions.

    PubMed

    Wolfe, David E; Noguchi, Laura K

    2009-01-01

    The purpose of this study was to examine the use of music to sustain attention of young children during conditions of auditory distractions. Kindergarten students (N=76) were randomly assigned to one of four conditions/groups: (a) spoken story with no distraction, (b) spoken story with distraction, (c) musical story with no distraction, musical story with distraction. Participants were asked to listen to the story and to identify specific "actions" and "animals" that were presented (i.e., spoken or sung) within the story. A tally of correct responses (child pointed to correct actions/animals at appropriate times) was recorded during the listening task. Observations of participants' behaviors while listening were also made by the experimenter using narrative recording procedures. A one-way ANOVA was computed to assess the difference in mean scores across the four experimental conditions. Significant results were found. Further analysis employing a Tukey post hoc/multiple comparisons test revealed significant differences between the spoken story with distraction condition and the musical story with distraction condition. These statistical results, along with the observations of listening behaviors, were discussed in terms of providing suggestions for future research and in lending support to the use of music with young children to improve vigilance within educational and clinical settings. PMID:19256733

  10. Neurobehavioral Effects of Space Radiation on Psychomotor Vigilance Tests

    NASA Astrophysics Data System (ADS)

    Hienz, Robert; Davis, Catherine; Weed, Michael; Guida, Peter; Gooden, Virginia; Brady, Joseph; Roma, Peter

    Neurobehavioral Effects of Space Radiation on Psychomotor Vigilance Tests INTRODUCTION Risk assessment of the biological consequences of living in the space radiation environment represents one of the highest priority areas of NASA radiation research. Of critical importance is the need for a risk assessment of damage to the central nervous system (CNS) leading to functional cognitive/behavioral changes during long-term space missions, and the development of effective shielding or biological countermeasures to such risks. The present research focuses on the use of an animal model that employs neurobehavioral tests identical or homologous to those currently in use in human models of risk assessment by U.S. agencies such as the Depart-ment of Defense and Federal Aviation and Federal Railroad Administrations for monitoring performance and estimating accident risks associated with such variables as fatigue and/or alcohol or drug abuse. As a first approximation for establishing human risk assessments due to exposure to space radiation, the present work provides animal performance data obtained with the rPVT (rat Psychomotor Vigilance Test), an animal analog of the human PVT that is currently employed for human risk assessments via quantification of sustained attention (e.g., 'vigilance' or 'readiness to perform' tasks). Ground-based studies indicate that radiation can induce neurobehavioral changes in rodents, including impaired performance on motor tasks and deficits in spatial learning and memory. The present study is testing the hypothesis that radiation exposure impairs motor function, performance accuracy, vigilance, motivation, and memory in adult male rats. METHODS The psychomotor vigilance test (PVT) was originally developed as a human cognitive neurobe-havioral assay for tracking the temporally dynamic changes in sustained attention, and has also been used to track changes in circadian rhythm. In humans the test requires responding to a small, bright

  11. Predicting vigilance: a fresh look at an old problem.

    PubMed

    Finomore, V; Matthews, G; Shaw, T; Warm, J

    2009-07-01

    Individual differences in vigilance are ubiquitous and relevant to a variety of work environments in industrial, transportation, medical and security settings. Despite much previous work, mostly on personality traits, it remains difficult to identify vigilant operators. This paper reviews recent research that may point towards practically useful predictor variables for vigilance. Theoretical approaches to identifying predictors that accommodate the heterogeneous nature of vigilance tasks are compared. The article surveys recent empirical studies using personality measures, ability tests and scales for stress and coping as predictors of vigilance. Promising new constructs include trait scales linked to fatigue, abnormal personality and the stress state of task engagement. Implications of the data reviewed for occupational selection are discussed. Selection should be based on a multivariate assessment strategy, cognitive task analysis of the operational vigilance task and use of work sample measures to capture typical stress responses to the task. This review paper surveys recent research that may point towards practically useful predictor variables for vigilance. The article surveys recent empirical studies using personality measures, ability tests and scales for stress and coping as predictors of vigilance. Selection should be based on a multivariate assessment strategy. PMID:19562590

  12. Decoding Vigilance with NIRS

    PubMed Central

    Bogler, Carsten; Mehnert, Jan; Steinbrink, Jens; Haynes, John-Dylan

    2014-01-01

    Sustained, long-term cognitive workload is associated with variations and decrements in performance. Such fluctuations in vigilance can be a risk factor especially during dangerous attention demanding activities. Functional MRI studies have shown that attentional performance is correlated with BOLD-signals, especially in parietal and prefrontal cortical regions. An interesting question is whether these BOLD-signals could be measured in real-world scenarios, say to warn in a dangerous workplace whenever a subjects' vigilance is low. Because fMRI lacks the mobility needed for such applications, we tested whether the monitoring of vigilance might be possible using Near-Infrared Spectroscopy (NIRS). NIRS is a highly mobile technique that measures hemodynamics in the surface of the brain. We demonstrate that non-invasive NIRS signals correlate with vigilance. These signals carry enough information to decode subjects' reaction times at a single trial level. PMID:25032963

  13. Vigilance and Sustained Attention in Children and Adults with ADHD

    ERIC Educational Resources Information Center

    Tucha, Lara; Tucha, Oliver; Walitza, Susanne; Sontag, Thomas A.; Laufkotter, Rainer; Linder, Martin; Lange, Klaus W.

    2009-01-01

    Objective: The present article tests the hypothesis of a sustained attention deficit in children and adults suffering from ADHD. Method: Vigilance and sustained attention of 52 children with ADHD and 38 adults with ADHD were assessed using a computerized vigilance task. Furthermore, the attentional performance of healthy children (N = 52) and…

  14. Sleepiness and vigilance tests.

    PubMed

    Mathis, J; Hess, C W

    2009-04-18

    Objective assessments of subjective complaints such as sleepiness, tiredness or fatigue using sleepiness and vigilance tests aim to identify its causes and to judge the fitness to drive or to work of the affected person. "Vigilance" comprises wakefulness, alertness and attention and is therefore not merely reciprocal to sleepiness. Since it is a complex phenomenon with several dimensions it is unlikely to be appropriately assessed by one single "vigilance test". One important dimension of vigilance discussed here is wakefulness with its counterpart of overt sleep and the whole spectrum of various levels in between. The transit zone between full wakefulness and overt sleep is mainly characterised by the subjective complaint of sleepiness, which cannot be measured directly. Only the consequences of reduced wakefulness such as a shortened sleep latency, slowed cognitive function and prolonged reaction time can be measured objectively. It is, therefore, more promising to combine a battery of subjective and objective tests to answer a specific question in order to achieve the most appropriate description for a given clinical or medicolegal situation. However even then we must keep in mind that many other important aspects of fitness to drive / fitness to work such as neurological, psychiatric and neuropsychological functions including risk taking behaviour are not covered by vigilance tests. A comprehensive, multidisciplinary approach is essential in such situations. PMID:19418304

  15. Vigilance: A Review of the Literature and Applications to Sentry Duty

    SciTech Connect

    See, Judi E.

    2014-09-01

    Vigilance , or sustained attention, involves the ability to maintain focus and remain alert for prolonged periods of time. Problems associated with the ability to sustain attention were first identified in real-world combat situations during World War II, and they continue to abound and evolve as new and different types of situations requiring vigilance arise. This paper provides a review of the vigilance literature that describes the primary psychophysical, task, environmental, pharmacological, and individual factors that impact vigilance performance. The paper also describes how seminal findings from vigilance research apply specifically to the task of sentry duty. The strengths and weaknesses of a human sentry and options to integrate human and automated functions for vigilance tasks are discussed. Finally, techniques that may improve vigilance performance for sentry duty tasks are identified.

  16. Anticipation of Monetary Reward Can Attenuate the Vigilance Decrement

    PubMed Central

    Grosso, Mallory; Liu, Guanyu; Mitko, Alex; Morris, Rachael; DeGutis, Joseph

    2016-01-01

    Motivation and reward can have differential effects on separate aspects of sustained attention. We previously demonstrated that continuous reward/punishment throughout a sustained attention task improves overall performance, but not vigilance decrements. One interpretation of these findings is that vigilance decrements are due to resource depletion, which is not overcome by increasing overall motivation. However, an alternative explanation is that as one performs a continuously rewarded task there are less potential gains/losses as the task progresses, which could decrease motivation over time, producing a vigilance decrement. This would predict that keeping future gains/losses consistent throughout the task would reduce the vigilance decrement. In the current study, we examined this possibility by comparing two versions (continuous-small loss vs. anticipate-large loss) of a 10-minute gradual onset continuous performance task (gradCPT), a challenging go/no-go sustained attention task. Participants began each task with the potential to keep $18. In the continuous-small-loss version, small monetary losses were accrued continuously throughout the task for each error. However, in the anticipate-large-loss version, participants lost all $18 if they erroneously responded to one target that always appeared toward the end of the vigil. Typical vigilance decrements were observed in the continuous-small-loss condition. In the anticipate-large-loss condition, vigilance decrements were reduced, particularly when the anticipate-large loss condition was completed second. This suggests that the looming possibility of a large loss can attenuate the vigilance decrement and that this attenuation may occur most consistently after sufficient task experience. We discuss these results in the context of current theories of sustained attention. PMID:27472785

  17. Anticipation of Monetary Reward Can Attenuate the Vigilance Decrement.

    PubMed

    Esterman, Michael; Grosso, Mallory; Liu, Guanyu; Mitko, Alex; Morris, Rachael; DeGutis, Joseph

    2016-01-01

    Motivation and reward can have differential effects on separate aspects of sustained attention. We previously demonstrated that continuous reward/punishment throughout a sustained attention task improves overall performance, but not vigilance decrements. One interpretation of these findings is that vigilance decrements are due to resource depletion, which is not overcome by increasing overall motivation. However, an alternative explanation is that as one performs a continuously rewarded task there are less potential gains/losses as the task progresses, which could decrease motivation over time, producing a vigilance decrement. This would predict that keeping future gains/losses consistent throughout the task would reduce the vigilance decrement. In the current study, we examined this possibility by comparing two versions (continuous-small loss vs. anticipate-large loss) of a 10-minute gradual onset continuous performance task (gradCPT), a challenging go/no-go sustained attention task. Participants began each task with the potential to keep $18. In the continuous-small-loss version, small monetary losses were accrued continuously throughout the task for each error. However, in the anticipate-large-loss version, participants lost all $18 if they erroneously responded to one target that always appeared toward the end of the vigil. Typical vigilance decrements were observed in the continuous-small-loss condition. In the anticipate-large-loss condition, vigilance decrements were reduced, particularly when the anticipate-large loss condition was completed second. This suggests that the looming possibility of a large loss can attenuate the vigilance decrement and that this attenuation may occur most consistently after sufficient task experience. We discuss these results in the context of current theories of sustained attention. PMID:27472785

  18. Oxytocin blunts social vigilance in the rhesus macaque

    PubMed Central

    Ebitz, R. Becket; Watson, Karli K.; Platt, Michael L.

    2013-01-01

    Exogenous application of the neuromodulatory hormone oxytocin (OT) promotes prosocial behavior and can improve social function. It is unclear, however, whether OT promotes prosocial behavior per se, or whether it facilitates social interaction by reducing a state of vigilance toward potential social threats. To disambiguate these two possibilities, we exogenously delivered OT to male rhesus macaques, which have a characteristic pattern of species-typical social vigilance, and examined their performance in three social attention tasks. We first determined that, in the absence of competing task demands or goals, OT increased attention to faces and eyes, as in humans. By contrast, OT reduced species typical social vigilance for unfamiliar, dominant, and emotional faces in two additional tasks. OT eliminated the emergence of a typical state of vigilance when dominant face images were available during a social image choice task. Moreover, OT improved performance on a reward-guided saccade task, despite salient social distractors: OT reduced the interference of unfamiliar faces, particularly emotional ones, when these faces were task irrelevant. Together, these results demonstrate that OT suppresses vigilance toward potential social threats in the rhesus macaque. We hypothesize that a basic role for OT in regulating social vigilance may have facilitated the evolution of prosocial behaviors in humans. PMID:23798448

  19. Materials vigilance and traceability.

    PubMed

    Tracol, P

    2016-02-01

    Patient safety requires speedy detection of any medical device malfunction; this is known as "materials vigilance". It entails the need to be able to trace back the life-long pathway of a device; this is "traceability". European regulations enact free circulation of medical devices throughout the European Union, with each member state being responsible for safety within its own territory. Medical devices are divided into 3 categories of increasing risk. CE marking mandatory for medical devices distributed within the EU, and count as market authorizations. They are delivered with 5-year validity by what is known as a "notified body". Health authorities are responsible for monitoring the market and any incidents. New regulations are presently being drawn up to improve efficiency and transparency. Materials vigilance is founded on mandatory declaration of medical device incidents. At local level, it comprises local reporters responsible for informing the National Health Products Safety Agency (Agence nationale de sécurité du médicament et des produits de santé [ANSM]) of any incidents and taking all necessary precautions. At national level, the ANSM assesses the safety, efficacy and quality of healthcare products; it centralizes and assesses materials vigilance reports and takes the requisite decisions. Materials vigilance is further organized at the European and international levels, to harmonize legislation regarding medical devices. Traceability is intended to rapidly identify medical device bearers in case of product recall. Each center is to organize the traceability of its devices; manufacturers' obligation of traceability ceases with the healthcare establishment or user. CE marking involves strict labeling rules to ensure safety of use. A change in the organization of traceability is presently underway, in the form of international Unique Device Identifiers, with harmonized label data, barcodes and standardized terminology. A European and later

  20. Semi-automated CCTV surveillance: the effects of system confidence, system accuracy and task complexity on operator vigilance, reliance and workload.

    PubMed

    Dadashi, N; Stedmon, A W; Pridmore, T P

    2013-09-01

    Recent advances in computer vision technology have lead to the development of various automatic surveillance systems, however their effectiveness is adversely affected by many factors and they are not completely reliable. This study investigated the potential of a semi-automated surveillance system to reduce CCTV operator workload in both detection and tracking activities. A further focus of interest was the degree of user reliance on the automated system. A simulated prototype was developed which mimicked an automated system that provided different levels of system confidence information. Dependent variable measures were taken for secondary task performance, reliance and subjective workload. When the automatic component of a semi-automatic CCTV surveillance system provided reliable system confidence information to operators, workload significantly decreased and spare mental capacity significantly increased. Providing feedback about system confidence and accuracy appears to be one important way of making the status of the automated component of the surveillance system more 'visible' to users and hence more effective to use. PMID:22704458

  1. Vigilance Deficit in Learning Disabled Children: A Signal Detection Analysis.

    ERIC Educational Resources Information Center

    Swanson, Lee

    1981-01-01

    Tested whether learning disabled children start a vigilance task (1) with the same capacity or detectability as nondisabled children but decline as time on task increases; (2) at a lower level of stimulus detectability due to a reduced capacity for information processing but do not decline in attention faster than nondisabled children. (Author/DB)

  2. EEG predictors of covert vigilant attention

    NASA Astrophysics Data System (ADS)

    Martel, Adrien; Dähne, Sven; Blankertz, Benjamin

    2014-06-01

    Objective. The present study addressed the question whether neurophysiological signals exhibit characteristic modulations preceding a miss in a covert vigilant attention task which mimics a natural environment in which critical stimuli may appear in the periphery of the visual field. Approach. Subjective, behavioural and encephalographic (EEG) data of 12 participants performing a modified Mackworth Clock task were obtained and analysed offline. The stimulus consisted of a pointer performing regular ticks in a clockwise sequence across 42 dots arranged in a circle. Participants were requested to covertly attend to the pointer and press a response button as quickly as possible in the event of a jump, a rare and random event. Main results. Significant increases in response latencies and decreases in the detection rates were found as a function of time-on-task, a characteristic effect of sustained attention tasks known as the vigilance decrement. Subjective sleepiness showed a significant increase over the duration of the experiment. Increased activity in the α-frequency range (8-14 Hz) was observed emerging and gradually accumulating 10 s before a missed target. Additionally, a significant gradual attenuation of the P3 event-related component was found to antecede misses by 5 s. Significance. The results corroborate recent findings that behavioural errors are presaged by specific neurophysiological activity and demonstrate that lapses of attention can be predicted in a covert setting up to 10 s in advance reinforcing the prospective use of brain-computer interface (BCI) technology for the detection of waning vigilance in real-world scenarios. Combining these findings with real-time single-trial analysis from BCI may pave the way for cognitive states monitoring systems able to determine the current, and predict the near-future development of the brain's attentional processes.

  3. Wireless and wearable EEG system for evaluating driver vigilance.

    PubMed

    Lin, Chin-Teng; Chuang, Chun-Hsiang; Huang, Chih-Sheng; Tsai, Shu-Fang; Lu, Shao-Wei; Chen, Yen-Hsuan; Ko, Li-Wei

    2014-04-01

    Brain activity associated with attention sustained on the task of safe driving has received considerable attention recently in many neurophysiological studies. Those investigations have also accurately estimated shifts in drivers' levels of arousal, fatigue, and vigilance, as evidenced by variations in their task performance, by evaluating electroencephalographic (EEG) changes. However, monitoring the neurophysiological activities of automobile drivers poses a major measurement challenge when using a laboratory-oriented biosensor technology. This work presents a novel dry EEG sensor based mobile wireless EEG system (referred to herein as Mindo) to monitor in real time a driver's vigilance status in order to link the fluctuation of driving performance with changes in brain activities. The proposed Mindo system incorporates the use of a wireless and wearable EEG device to record EEG signals from hairy regions of the driver conveniently. Additionally, the proposed system can process EEG recordings and translate them into the vigilance level. The study compares the system performance between different regression models. Moreover, the proposed system is implemented using JAVA programming language as a mobile application for online analysis. A case study involving 15 study participants assigned a 90 min sustained-attention driving task in an immersive virtual driving environment demonstrates the reliability of the proposed system. Consistent with previous studies, power spectral analysis results confirm that the EEG activities correlate well with the variations in vigilance. Furthermore, the proposed system demonstrated the feasibility of predicting the driver's vigilance in real time. PMID:24860041

  4. Pharmacovigilance is... Vigilance.

    PubMed

    Edwards, I Ralph; Bencheikh, Rachida Soulayamani

    2016-04-01

    The world changes continuously and pharmacovigilance as a new discipline also must change. There are new fields opening with novel challenges whilst we are still perfecting ways to manage and improve the basic challenges such as inadequate data for decision making and under-reporting. Traditional medicines, vaccines, poisoning and medication error are all aspects of the safety of medicines that we have monitored for decades, though without perhaps paying enough attention to their special aspects. There are many new stakeholders taking serious interest in pharmacovigilance outside the regulatory sphere and they often focus on improving individual patient care, rather than the more traditional concentration on broad public health. The same stakeholders are also drawing attention to other iatrogenic outcomes that should be recognised, evaluated and their outcomes compared and contrasted with medication, such as harm from medical devices. The vigilance methods used for medication are very much applicable to all these new fields, though more and different expertise will be needed to evaluate outcomes. PMID:26692393

  5. EEG and Eye Tracking Demonstrate Vigilance Enhancement with Challenge Integration

    PubMed Central

    Bodala, Indu P.; Li, Junhua; Thakor, Nitish V.; Al-Nashash, Hasan

    2016-01-01

    Maintaining vigilance is possibly the first requirement for surveillance tasks where personnel are faced with monotonous yet intensive monitoring tasks. Decrement in vigilance in such situations could result in dangerous consequences such as accidents, loss of life and system failure. In this paper, we investigate the possibility to enhance vigilance or sustained attention using “challenge integration,” a strategy that integrates a primary task with challenging stimuli. A primary surveillance task (identifying an intruder in a simulated factory environment) and a challenge stimulus (periods of rain obscuring the surveillance scene) were employed to test the changes in vigilance levels. The effect of integrating challenging events (resulting from artificially simulated rain) into the task were compared to the initial monotonous phase. EEG and eye tracking data is collected and analyzed for n = 12 subjects. Frontal midline theta power and frontal theta to parietal alpha power ratio which are used as measures of engagement and attention allocation show an increase due to challenge integration (p < 0.05 in each case). Relative delta band power of EEG also shows statistically significant suppression on the frontoparietal and occipital cortices due to challenge integration (p < 0.05). Saccade amplitude, saccade velocity and blink rate obtained from eye tracking data exhibit statistically significant changes during the challenge phase of the experiment (p < 0.05 in each case). From the correlation analysis between the statistically significant measures of eye tracking and EEG, we infer that saccade amplitude and saccade velocity decrease with vigilance decrement along with frontal midline theta and frontal theta to parietal alpha ratio. Conversely, blink rate and relative delta power increase with vigilance decrement. However, these measures exhibit a reverse trend when challenge stimulus appears in the task suggesting vigilance enhancement. Moreover, the mean

  6. EEG and Eye Tracking Demonstrate Vigilance Enhancement with Challenge Integration.

    PubMed

    Bodala, Indu P; Li, Junhua; Thakor, Nitish V; Al-Nashash, Hasan

    2016-01-01

    Maintaining vigilance is possibly the first requirement for surveillance tasks where personnel are faced with monotonous yet intensive monitoring tasks. Decrement in vigilance in such situations could result in dangerous consequences such as accidents, loss of life and system failure. In this paper, we investigate the possibility to enhance vigilance or sustained attention using "challenge integration," a strategy that integrates a primary task with challenging stimuli. A primary surveillance task (identifying an intruder in a simulated factory environment) and a challenge stimulus (periods of rain obscuring the surveillance scene) were employed to test the changes in vigilance levels. The effect of integrating challenging events (resulting from artificially simulated rain) into the task were compared to the initial monotonous phase. EEG and eye tracking data is collected and analyzed for n = 12 subjects. Frontal midline theta power and frontal theta to parietal alpha power ratio which are used as measures of engagement and attention allocation show an increase due to challenge integration (p < 0.05 in each case). Relative delta band power of EEG also shows statistically significant suppression on the frontoparietal and occipital cortices due to challenge integration (p < 0.05). Saccade amplitude, saccade velocity and blink rate obtained from eye tracking data exhibit statistically significant changes during the challenge phase of the experiment (p < 0.05 in each case). From the correlation analysis between the statistically significant measures of eye tracking and EEG, we infer that saccade amplitude and saccade velocity decrease with vigilance decrement along with frontal midline theta and frontal theta to parietal alpha ratio. Conversely, blink rate and relative delta power increase with vigilance decrement. However, these measures exhibit a reverse trend when challenge stimulus appears in the task suggesting vigilance enhancement. Moreover, the mean reaction

  7. Vigilance: the essence of nursing.

    PubMed

    Meyer, Geralyn; Lavin, Mary Ann

    2005-09-01

    Nursing, perhaps more than any other health care profession, claims caring as fundamental to its practice. Professional vigilance is the essence of caring in nursing. This article uses historical and theoretical bases to define professional vigilance and discuss its components. Two types of nursing diagnoses, central and surveillance, are proposed. Central diagnoses indicate the need for the nurse to plan and implement interventions for the achievement of outcomes. North American Nursing Diagnosis Association (NANDA)-approved diagnoses fall in this category. Surveillance diagnoses are those that recognize patient risks that are anticipated by the nurse, who remains ready to act in the event of occurrence. The profession, as a whole, and language developers, in particular, need to expand standardized nursing diagnosis terminology so that the contribution of nurses' vigilance to patient safety may be effectively communicated and documented. PMID:16225388

  8. Effect of guanfacine on vigilance

    PubMed Central

    Heidbreder, E.; Pagel, G.; Roeckel, A.; Heidland, A.

    1980-01-01

    1 In 20 patients suffering from mild hypertension (WHO classification I-II) the effect on vigilance was studied under double-blind conditions. Ten patients were given guanfacine 2 mg daily and ten others a placebo preparation. 2 Before the study and following 2 weeks' medication a battery of tests was applied in which the reaction time and attention were subjected to comparative analysis. The variation in blood pressure and heart rate under mental stress conditions was also tested. 3 The study shows a non-significant reduction in blood pressure in the guanfacine group without the parameters of vigilance being affected. Under mental stress, there was no impairment of haemodynamic reactions. 4 It is concluded that guanfacine, at the selected dose of 2 mg daily, has no apparent effect on the vigilance of hypertensive patients. PMID:6994772

  9. A multi level system design for vigilance measurement based on head posture estimation and eyes blinking

    NASA Astrophysics Data System (ADS)

    Teyeb, Ines; Jemai, Olfa; Zaied, Mourad; ben Amar, Chokri

    2015-12-01

    Driving security is an important task for human society. The major challenge in the field of accident avoidance systems is the driver vigilance monitoring. The lack of vigilance can be noticed by various ways, such as, fatigue, drowsiness and distraction. Hence, the need of a reliable driver's vigilance decrease detection system which can alert drivers before a mishap happens. In this paper, we present a novel approach for vigilance estimation based on multilevel system by combining head movement analysis and eyes blinking. We have used Viola and Jones algorithm to analyse head movement and a classification system using wavelet networks for eyelid closure measuring. The contribution of our application is classifiying the vigilance state at multi level. This is different from the binary-class (awakening or hypovigilant state) existing in most popular systems.

  10. Vigilance problems in orbiter processing

    NASA Technical Reports Server (NTRS)

    Swart, William W.; Safford, Robert R.; Kennedy, David B.; Yadi, Bert A.; Barth, Timothy S.

    1993-01-01

    A pilot experiment was done to determine what factors influence potential performance errors related to vigilance in Orbiter processing activities. The selected activities include post flight inspection for burned gap filler material and pre-rollout inspection for tile processing shim material. It was determined that the primary factors related to performance decrement were the color of the target and the difficulty of the target presentation.

  11. Work exposure and vigilance decrements in closed circuit television surveillance.

    PubMed

    Donald, Fiona; Donald, Craig; Thatcher, Andrew

    2015-03-01

    The aim of this study was to examine operator effectiveness in terms of detection rates and potential vigilance decrements in a proactive or real time CCTV surveillance task. The study was conducted in two stages. During stage one, 42 operators who were employed full-time in CCTV surveillance observed a 90-min video and were required to detect four types of target behaviours. No vigilance decrement was found for this sample as a whole. Stage two involved collecting additional data from 31 novices and dividing the existing operators into two sub-samples, consisting of generalists and specialists depending on the type of surveillance they performed at work (total N = 73). Fifty percent of target behaviours were detected and false alarms were high. Vigilance decrements were found for novices and generalists, but specialists maintained their performance for the first hour and then increased it. Results are discussed in terms of surveillance background, work exposure, transfer of learning, selection, training and motivation and the impact of these on vigilance and CCTV performance. PMID:25479991

  12. REM sleep and the concept of vigilance.

    PubMed

    Tolaas, J

    1978-02-01

    Several writers, notably Montague Ullman and Frederick Snyder, conceive of REM sleep and the associated state of vivid dreaming as periods of vigilance. In Ullman's conceptualization, the emphasis is on dreaming in humans, whereas Snyder is concerned with REM sleep (activated sleep) in subhuman organisms. In this paper several objections to the sentinel and vigilance theories are raised, and a modified concept of vigilance, linking it with learning and memory, is put forward. PMID:203343

  13. Pupil size and social vigilance in rhesus macaques

    PubMed Central

    Ebitz, R. Becket; Pearson, John M.; Platt, Michael L.

    2014-01-01

    Complex natural environments favor the dynamic alignment of neural processing between goal-relevant stimuli and conflicting but biologically salient stimuli like social competitors or predators. The biological mechanisms that regulate dynamic changes in vigilance have not been fully elucidated. Arousal systems that ready the body to respond adaptively to threat may contribute to dynamic regulation of vigilance. Under conditions of constant luminance, pupil diameter provides a peripheral index of arousal state. Although pupil size varies with the processing of goal-relevant stimuli, it remains unclear whether pupil size also predicts attention to biologically salient objects and events like social competitors, whose presence interferes with current goals. Here we show that pupil size in rhesus macaques both reflects the biological salience of task-irrelevant social distractors and predicts vigilance for these stimuli. We measured pupil size in monkeys performing a visual orienting task in which distractors—monkey faces and phase-scrambled versions of the same images—could appear in a congruent, incongruent, or neutral position relative to a rewarded target. Baseline pupil size under constant illumination predicted distractor interference, consistent with the hypothesis that pupil-linked arousal mechanisms regulate task engagement and distractibility. Notably, pupil size also predicted enhanced vigilance for social distractors, suggesting that pupil-linked arousal may adjust the balance of processing resources between goal-relevant and biologically important stimuli. The magnitude of pupil constriction in response to distractors closely tracked distractor interference, saccade planning and the social relevance of distractors, endorsing the idea that the pupillary light response is modulated by attention. These findings indicate that pupil size indexes dynamic changes in attention evoked by both the social environment and arousal. PMID:24834026

  14. Effects of signal salience and noise on performance and stress in an abbreviated vigil

    NASA Astrophysics Data System (ADS)

    Helton, William Stokely

    Vigilance or sustained attention tasks traditionally require observers to detect predetermined signals that occur unpredictably over periods of 30 min to several hours (Warm, 1984). These tasks are taxing and have been useful in revealing the effects of stress agents, such as infectious disease and drugs, on human performance (Alluisi, 1969; Damos & Parker, 1994; Warm, 1993). However, their long duration has been an inconvenience. Recently, Temple and his associates (Temple et al., 2000) developed an abbreviated 12-min vigilance task that duplicates many of the findings with longer duration vigils. The present study was designed to explore further the similarity of the abbreviated task to long-duration vigils by investigating the effects of signal salience and jet-aircraft engine noise on performance, operator stress, and coping strategies. Forty-eight observers (24 males and 24 females) were assigned at random to each of four conditions resulting from the factorial combination of signal salience (high and low contrast signals) and background noise (quiet and jet-aircraft noise). As is the case with long-duration vigils (Warm, 1993), signal detection in the abbreviated task was poorer for low salience than for high salience signals. In addition, stress scores, as indexed by the Dundee Stress State Questionnaire (Matthews, Joiner, Gilliland, Campbell, & Falconer, 1999), were elevated in the low as compared to the high salience condition. Unlike longer vigils, however, (Becker, Warm, Dember, & Hancock, 1996), signal detection in the abbreviated task was superior in the presence of aircraft noise than in quiet. Noise also attenuated the stress of the vigil, a result that is counter to previous findings regarding the effects of noise in a variety of other scenarios (Clark, 1984). Examination of observers' coping responses, as assessed by the Coping Inventory for Task Situations (Matthews & Campbell, 1998), indicated that problem-focused coping was the overwhelming

  15. The influence of essential oils on human vigilance.

    PubMed

    Heuberger, Eva; Ilmberger, Josef

    2010-09-01

    Olfactory stimuli are used in aromatherapy to enhance mood, well-being and work efficiency. Nevertheless, the impact of fragrances on cognitive performance in humans is not well understood. The present investigation aimed to evaluate the effects of 1,8-cineol, jasmine absolute ether, linalyl acetate and peppermint essential oil on human vigilance performance. The odorants were administered by means of inhalation and, except for peppermint essential oil, were tested at 2 different dosages. Performance in a standard visual vigilance task was measured in terms of speed and accuracy and subjective ratings of the odorants were assessed in terms of pleasantness, intensity, arousal and stress. We hypothesized that 1,8-cineol, jasmine absolute ether and peppermint essential oil would improve vigilance performance, whereas linalyl acetate would impair such performance. Comparison of the performances of the seven independent experimental groups with that of a control group did not show any of the expected effects. In contrast, inhalation of linalyl acetate decreased reaction times. Within-group analyses, however, revealed significant interactions between subjective ratings of the odorants and task performance. The results of the present investigation emphasize the high impact of subjective factors on the modulation of attentional functions by olfactory stimuli in humans. PMID:20923005

  16. Vigilance as a Response to White Complicity

    ERIC Educational Resources Information Center

    Applebaum, Barbara

    2013-01-01

    Calls for vigilance have been a recurrent theme in social justice education. Scholars making this call note that vigilance involves a continuous attentiveness, that it presumes some type of criticality, and that it is transformative. In this essay Barbara Applebaum expands upon some of these attributes and calls attention to three particular…

  17. Motivation in vigilance - Effects of self-evaluation and experimenter-controlled feedback.

    NASA Technical Reports Server (NTRS)

    Warm, J. S.; Kanfer, F. H.; Kuwada, S.; Clark, J. L.

    1972-01-01

    Vigilance experiments have been performed to study the relative efficiency of feedback operations in enhancing vigilance performance. Two feedback operations were compared - i.e., experimenter-controlled feedback in the form of knowledge of results (KR) regarding response times to signal detections, and subject-controlled feedback in the form of self-evaluation (SE) of response times to signal detections. The subjects responded to the aperiodic offset of a visual signal during a 1-hr vigil. Both feedback operations were found to enhance performance efficiency: subjects in the KR and SE conditions had faster response times than controls receiving no evaluative feedback. Moreover, the data of the KR and SE groups did not differ significantly from each other. The results are discussed in terms of the hypothesis that self-evaluation is a critical factor underlying the incentive value of KR in vigilance tasks.

  18. Autonomic hyper-vigilance in post-infective fatigue syndrome.

    PubMed

    Kadota, Yumiko; Cooper, Gavin; Burton, Alexander R; Lemon, Jim; Schall, Ulrich; Lloyd, Andrew; Vollmer-Conna, Ute

    2010-09-01

    This study examined whether post-infective fatigue syndrome (PIFS) is associated with a disturbance in bidirectional autonomic signalling resulting in heightened perception of symptoms and sensations from the body in conjunction with autonomic hyper-reactivity to perceived challenges. We studied 23 patients with PIFS and 25 healthy matched control subjects. A heartbeat discrimination task and a pressure pain threshold test were used to assess interoceptive sensitivity. Cardiac response was assessed over a 4-min Stroop task. PIFS was associated with higher accuracy in heartbeat discrimination and a lower pressure pain threshold. Increased interoceptive sensitivity correlated strongly with current symptoms and potentiated differences in the cardiac response to the Stroop task, which in PIFS was characterized by insensitivity to task difficulty and lack of habituation. Our results provide the first evidence of heightened interoceptive sensitivity in PIFS. Together with the distinct pattern in cardiac responsivity these findings present a picture of physiological hyper-vigilance and response inflexibility. PMID:20678991

  19. The effects of sleep debt on vigilance in young drivers: an education/research project in high schools.

    PubMed

    Lucidi, Fabio; Devoto, Alessandra; Bertini, Mario; Braibanti, Paride; Violani, Cristiano

    2002-08-01

    The vigilance levels of a group of 59 students were assessed in the daytime (9:00-11:00 a.m.) and again early Sunday morning (2:30-5:00 a.m.), and were then compared. Data were collected at the students' schools. The differences in performance impairment associated with different Saturday night social activities and the effect of alcohol consumption were evaluated. Results indicate a vigilance decrease during the night, and this is greater in subjects who consumed more alcohol. Students who spent their Saturday night in a discotheque showed the most prominent nocturnal vigilance decrease, even when the effect of alcohol consumption is covaried. The effect of social activities on vigilance levels was also associated with different lengths of time spent awake and the different time in which subjects performed the vigilance task. PMID:12175997

  20. The Academic Legacy of Berta Vigil Laden

    ERIC Educational Resources Information Center

    Hagedorn, Linda Serra

    2007-01-01

    Berta Vigil Laden was a scholar who helped raise our understanding of minority-serving institutions generally and Hispanic-serving institutions in particular. She approached her work with empathy and compassion. This article reviews her major contributions.

  1. Target acquisition with UAVs: vigilance displays and advanced cuing interfaces.

    PubMed

    Gunn, Daniel V; Warm, Joel S; Nelson, W Todd; Bolia, Robert S; Schumsky, Donald A; Corcoran, Kevin J

    2005-01-01

    Vigilance and threat detection are critical human factors considerations in the control of unmanned aerial vehicles (UAVs). Utilizing a vigilance task in which threat detections (critical signals) led observers to perform a subsequent manual target acquisition task, this study provides information that might have important implications for both of these considerations in the design of future UAV systems. A sensory display format resulted in more threat detections, fewer false alarms, and faster target acquisition times and imposed a lighter workload than did a cognitive display format. Additionally, advanced visual, spatial-audio, and haptic cuing interfaces enhanced acquisition performance over no cuing in the target acquisition phase of the task, and they did so to a similar degree. Thus, in terms of potential applications, this research suggests that a sensory format may be the best display format for threat detection by future UAV operators, that advanced cuing interfaces may prove useful in future UAV systems, and that these interfaces are functionally interchangeable. PMID:16435691

  2. The Relationship between Regular Sports Participation and Vigilance in Male and Female Adolescents

    PubMed Central

    Ballester, Rafael; Huertas, Florentino; Yuste, Francisco Javier; Llorens, Francesc; Sanabria, Daniel

    2015-01-01

    The present study investigated the relationship between regular sport participation (soccer) and vigilance performance. Two groups of male and female adolescents differentiated in terms of their sport participation (athletes, n = 39, and non-athletes, n = 36) took part in the study. In one session, participants performed the Leger Multi-stage fitness test to estimate their aerobic fitness level. In the other session, participants completed the Psychomotor Vigilance Task (PVT) to evaluate their vigilance performance. Perceived arousal prior to the task and motivation toward the task were also measured in the PVT session. The results revealed that athletes had better cardiovascular fitness and showed better performance in the PVT. However, correlation analyses did not show any significant relationship between cardiovascular fitness and performance in the PVT. Athletes showed larger scores in motivation and perceived arousal measures with respect to non-athletes, although, once again, these variables were not correlated with PVT performance. Gender differences were observed only in the Leger test, with males showing greater fitness level than females. The major outcome of this research points to a positive relationship between regular sport participation and vigilance during adolescence. This relationship did not seem to be influenced by gender, perceived arousal, motivation toward the task or cardiovascular fitness. We discuss our results in terms of the different hypotheses put forward in the literature to explain the relationship between physical activity and cognitive functioning. PMID:25849873

  3. Tactual and auditory vigilance in split-brain man.

    PubMed Central

    Dimond, S J

    1979-01-01

    Two studies are reported of tactual and auditory vigilance performance in patients with a split-brain or partial commissurotomy to examine the attentional behaviour of the right and left hemisphere, and to identify defects in attention which may be related to the division of the cerebral commissures. The performance of the right hemisphere on all tasks of sustained attention so far studied was substantially better than that of the left. Considerable depletion of concentration was observed for the total split-brain group but not in patients with partial commissurotomy. One of the more unusual phenomena of the split-brain condition is that gaps of attention, often lasting many seconds, occur predominantly on the left hemisphere. The switch to a different type of signal on the same hemisphere does not stop them but the switching of signals from one hemisphere to another does. The defect is interpreted as a failure of attention peculiar to the individual hemisphere under test. PMID:762586

  4. Polytope ARTMAP: pattern classification without vigilance based on general geometry categories.

    PubMed

    Gomes Amorim, Dinani; Fernández Delgado, Manuel; Barro Ameneiro, Senén

    2007-09-01

    This paper proposes polytope ARTMAP (PTAM), an adaptive resonance theory (ART) network for classification tasks which does not use the vigilance parameter. This feature is due to the geometry of categories in PTAM, which are irregular polytopes whose borders approximate the borders among the output predictions. During training, the categories expand only towards the input pattern without category overlap. The category expansion in PTAM is naturally limited by the other categories, and not by the category size, so the vigilance is not necessary. PTAM works in a fully automatic way for pattern classification tasks, without any parameter tuning, so it is easier to employ for nonexpert users than other classifiers. PTAM achieves lower error than the leading ART networks on a complete collection of benchmark data sets, except for noisy data, without any parameter optimization. PMID:18220182

  5. Vigilance in the laboratory predicts avoidance in the real world: A dimensional analysis of neural, behavioral, and ecological momentary data in anxious youth.

    PubMed

    Price, Rebecca B; Allen, Kristy Benoit; Silk, Jennifer S; Ladouceur, Cecile D; Ryan, Neal D; Dahl, Ronald E; Forbes, Erika E; Siegle, Greg J

    2016-06-01

    Vigilance and avoidance of threat are observed in anxious adults during laboratory tasks, and are posited to have real-world clinical relevance, but data are mixed in anxious youth. We propose that vigilance-avoidance patterns will become evident in anxious youth through a focus on individual differences and real-world strategic avoidance. Decreased functional connectivity between the amygdala and prefrontal cortex (PFC) could play a mechanistic role in this link. 78 clinically anxious youth completed a dot-probe task to assess vigilance to threat while undergoing fMRI. Real-world avoidance was assessed using Ecological Momentary Assessment (EMA) of self-reported suppression and distraction during negative life events. Vigilance toward threat was positively associated with EMA distraction and suppression. Functional connectivity between a right amygdala seed region and dorsomedial and right dorsolateral PFC regions was inversely related to EMA distraction. Dorsolateral PFC-amygdalar connectivity statistically mediated the relationship between attentional vigilance and real-world distraction. Findings suggest anxious youth showing attentional vigilance toward threat are more likely to use suppression and distraction to regulate negative emotions. Reduced PFC control over limbic reactivity is a possible neural substrate of this pattern. These findings lend ecological validity to laboratory vigilance assessments and suggest PFC-amygdalar connectivity is a neural mechanism bridging laboratory and naturalistic contexts. PMID:27010577

  6. The effects of theta-burst stimulation on sleep and vigilance in humans

    PubMed Central

    Mensen, Armand; Gorban, Corina; Niklaus, Marcel; Kuske, Eva; Khatami, Ramin

    2014-01-01

    Repetitive transcranial magnetic stimulation (TMS) has become a popular tool to modulate neuronal networks and associated brain functions in both clinical and basic research. Yet few studies have examined the potential effects of cortical stimulation on general levels of vigilance. In this exploratory study, we used theta-burst protocols, both continuous (cTBS) and intermittent (iTBS) patterns, to examine whether inhibition or excitation of the left dorso-lateral prefrontal cortex (dlPFC) was able to induce reliable and acute changes to vigilance measures, compared to the left dorso-lateral associative visual cortex (dlAVC) as a control site in line with previous work. Partially sleep restricted participants underwent four separate sessions in a single day, in a between subjects design for TBS stimulation type and within subjects for locaton, each consisting of maintenance of wakefulness test (MWT), a sleep latency test, and a psychomotor vigilance task (PVT). TBS significantly affected measures of sleep consolidation, namely latency to sleep stage 2 and sleep efficiency, but had no effects on sleep drive or psychomotor vigilance levels for either TBS type or location. Contrary to our initial hypothesis of the dlAVC as a control site, stimulation to this region resulted in the largest differential effects between stimulation types. Moreover, the effect of TBS was found to be consistent throughout the day. These data may provide the basis for further investigation into therapeutic applications of TBS in sleep disorders. PMID:24971057

  7. Slow release caffeine and prolonged (64-h) continuous wakefulness: effects on vigilance and cognitive performance.

    PubMed

    Beaumont, M; Batejat, D; Pierard, C; Coste, O; Doireau, P; Van Beers, P; Chauffard, F; Chassard, D; Enslen, M; Denis, J B; Lagarde, D

    2001-12-01

    Some long work or shift work schedules necessitate an elevated and prolonged level of vigilance and performance but often result in sleep deprivation (SD), fatigue and sleepiness, which may impair efficiency. This study investigated the effects of a slow-release caffeine [(SRC) at the daily dose of 600 mg] on vigilance and cognitive performance during a 64 h continuous wakefulness period. Sixteen healthy males volunteered for this double-blind, randomised, placebo controlled, two-way crossover study. A total of 300-mg SRC or placebo (PBO) was given twice a day at 21:00 and 9:00 h during the SD period. Vigilance was objectively assessed with continuous electroencephalogram (EEG), the multiple sleep latency tests (MSLT) and wrist actigraphy. Cognitive functions (information processing and working memory), selective and divided attention were determined with computerised tests from the AGARD-NATO STRES Battery (Standardised Tests for Research with Environmental Stressors). Attention was also assessed with a symbol cancellation task and a Stroop's test; alertness was appreciated from visual analogue scales (VAS). Tests were performed at the hypo (02:00-04:00 h, 14:00-16:00 h) and hypervigilance (10:00-12:00 h, 22:00-00:00 h) periods during SD. Central temperature was continuously measured and safety of treatment was assessed from repeated clinical examinations. Compared with PBO, MSLT showed that SRC subjects were more vigilant from the onset (P=0.001) to the end of SD (P < 0.0001) whereas some cognitive functions were improved till the thirty third of SD but others were ameliorated through all the SD period and alertness was better from the thirteenth hour of SD, as shown by Stroop's test (P=0.048). We showed that 300-mg SRC given twice daily during a 64-h SD is able to antagonize the impairment produced on vigilance and cognitive functions. PMID:11903856

  8. A Preliminary Investigation of the Reinforcement Function of Signal Detections in Simulated Baggage Screening: Further Support for the Vigilance Reinforcement Hypothesis

    ERIC Educational Resources Information Center

    Hogan, Lindsey C.; Bell, Matthew; Olson, Ryan

    2009-01-01

    The vigilance reinforcement hypothesis (VRH) asserts that errors in signal detection tasks are partially explained by operant reinforcement and extinction processes. VRH predictions were tested with a computerized baggage screening task. Our experiment evaluated the effects of signal schedule (extinction vs. variable interval 6 min) and visual…

  9. Automatic vigilance: the attention-grabbing power of negative social information.

    PubMed

    Pratto, F; John, O P

    1991-09-01

    One of the functions of automatic stimulus evaluation is to direct attention toward events that may have undesirable consequences for the perceiver's well-being. To test whether attentional resources are automatically directed away from an attended task to undesirable stimuli, Ss named the colors in which desirable and undesirable traits (e.g., honest, sadistic) appeared. Across 3 experiments, color-naming latencies were consistently longer for undesirable traits but did not differ within the desirable and undesirable categories. In Experiment 2, Ss also showed more incidental learning for undesirable traits, as predicted by the automatic vigilance (but not a perceptual defense) hypothesis. In Experiment 3, a diagnosticity (or base-rate) explanation of the vigilance effect was ruled out. The implications for deliberate processing in person perception and stereotyping are discussed. PMID:1941510

  10. Sleeping gulls monitor the vigilance behaviour of their neighbours

    PubMed Central

    Beauchamp, Guy

    2008-01-01

    Individuals in groups are often thought to scan their surroundings for threats independently of one another. Models, however, suggest that foragers should monitor the vigilance level of their neighbours to prevent cheating, and to gather information about incipient predation risk. Evidence for monitoring of vigilance is scant. Here, I examined changes in vigilance levels in sleeping gulls (Larus sp.) surrounded by neighbours in various states of alertness. Controlling for group size and neighbour density, gulls interrupted sleep more often to scan their surroundings, and were therefore more vigilant, when their neighbours were alert rather than sleeping or preening. The results provide evidence for copying of vigilance within groups of birds, suggesting a complex flow of information about predation risk in groups. PMID:18940772

  11. A vigilance model for latent learning.

    PubMed

    Boguslavsky, G W

    1978-01-01

    The author proposes a heuristic model for latent learning. It is concluded that to regard academic learning as qualitatively different from other forms of learning is to deny evolutionary continuity. Academic learning is not a unitary process governed by a single set of parameters. In addition, it is observed that the problem of student motivation may very well turn out to be purely academic. The instructional technique for a captive audience of a class may be so structured as to make the direction of attention irresistible, the performance of a response, when needed, compelling, and the acquisition of knowledge inevitable. Vigilance is an instance of innate foundation. Its most striking characteristics are its universality in the animal world, its ready evocation by a wide range of stimuli, and its apparent behavior and physiological manifestations. The last two are the natural resources for objective investigation, and the first may well be the basis of broad and valid generalizations. PMID:748845

  12. Foraging success in a wild species of bird varies depending on which eye is used for anti-predator vigilance.

    PubMed

    Beauchamp, Guy

    2013-01-01

    Brain lateralisation in animals with laterally placed eyes often leads to preferential eye use for ecologically relevant tasks such as monitoring predators and companions. Few studies of preferential eye use have been conducted in the wild and it is not clear if such preferences in the wild are widespread, how individuals can benefit from them, and which ecological factors influence their evolution. In a wild species of bird the extent to which foraging success varied depending on which eye is used during concomitant anti-predator vigilance was examined. When foraging in open mudflats, semipalmated sandpipers (Calidris pusilla) are frequently exposed to predation attempts by falcons (Falco spp) that originate from the tree cover bordering mudflats. Sandpipers spread along the receding tideline and can face the riskier side of their habitat primarily with the left or the right eye as they forage. If foraging is mostly incompatible with vigilance, the rate at which prey items are collected should decrease when birds use their less-preferred eye to scan cover. If foraging and vigilance can be carried out simultaneously, time spent foraging should not be affected but the efficiency with which their burrowing amphipod prey are located may be reduced, thus leading to decreased capture rate. Birds facing the riskier side of the habitat with their right eye captured significantly more prey than those scanning the same side with their left eye. Specialised eye use in sandpipers may allow individuals to perform simultaneous tasks, such as foraging and vigilance, more efficiently. PMID:22397500

  13. Prey synchronize their vigilant behaviour with other group members

    PubMed Central

    Pays, Olivier; Renaud, Pierre-Cyril; Loisel, Patrice; Petit, Maud; Gerard, Jean-François; Jarman, Peter J

    2007-01-01

    It is generally assumed that an individual of a prey species can benefit from an increase in the number of its group's members by reducing its own investment in vigilance. But what behaviour should group members adopt in relation to both the risk of being preyed upon and the individual investment in vigilance? Most models assume that individuals scan independently of one another. It is generally argued that it is more profitable for each group member owing to the cost that coordination of individual scans in non-overlapping bouts of vigilance would require. We studied the relationships between both individual and collective vigilance and group size in Defassa waterbuck, Kobus ellipsiprymnus defassa, in a population living under a predation risk. Our results confirmed that the proportion of time an individual spent in vigilance decreased with group size. However, the time during which at least one individual in the group scanned the environment (collective vigilance) increased. Analyses showed that individuals neither coordinated their scanning in an asynchronous way nor scanned independently of one another. On the contrary, scanning and non-scanning bouts were synchronized between group members, producing waves of collective vigilance. We claim that these waves are triggered by allelomimetic effects i.e. they are a phenomenon produced by an individual copying its neighbour's behaviour. PMID:17341457

  14. Cerebral hemovelocity reveals differential resource allocation strategies for extraverts and introverts during vigilance.

    PubMed

    Shaw, Tyler H; Nguyen, Cynthia; Satterfield, Kelly; Ramirez, Raul; McKnight, Patrick E

    2016-02-01

    Extraversion--one of the Big 5 personality factors--correlates negatively with vigilance, but most studies focus on performance outcomes and not the performance process. Previous research has shown that transcranial Doppler sonography (TCD), which measures cerebral blood flow velocity (CBFV), can be used to examine resource allocation strategies during vigilance performance. Hence, this study was designed to assess the attentional resource allocation strategies of introverts and extraverts using the CBFV measure. Twelve extroverts and 13 introverts monitored a 60-min vigilance task for a critical signal--the absence of a line on a five-circle array. The results revealed an overall performance decrement that was not modulated by extraversion. We observed an interaction between extraversion and time; CBFV declined in the introversion group, but not in the extraversion group. Additionally, an interaction between cerebral hemisphere and personality revealed that extraverts were recruiting resources from both the left and right cerebral hemispheres, while introverts only recruited resources from the right hemisphere. The results suggest that extraverts can allocate compensatory effort to mask performance differences. We discuss the theoretical and practical implications of these findings and offer future research directions that may help us understand these effects. PMID:26563163

  15. Family Care During End-of-Life Vigils.

    PubMed

    Fleming-Damon, Colleen

    2016-09-01

    An end-of-life vigil is the act of being with another toward death. A family vigil at end-of-life occurs when significant others gather by the bedside of dying individuals in the weeks, days, or hours prior to the death event. It is not unusual for nurses to be present, bear witness, and share in this human experience. This article reviews seminal and current research regarding the meaning and structure of the lived experience of vigil keeping for a dying family member, and translates research to inform nurses regarding family care during the transition at end-of-life. PMID:27497019

  16. Neighborhood Vigilance, Health Locus of Control, and Smoking Abstinence

    PubMed Central

    Reitzel, Lorraine R.; Lahoti, Sejal; Li, Yisheng; Cao, Yumei; Wetter, David W.; Waters, Andrew J.; Vidrine, Jennifer Irvin

    2012-01-01

    Objectives To examine whether health locus of control mediated relations of self-reported neighborhood vigilance and biochemically verified, continuous short-term smoking abstinence among 200 smokers enrolled in a cohort study. Methods A nonparametric bootstrapping procedure was used to assess mediation. Results Health locus of control-chance mediated relations between neighborhood vigilance and smoking abstinence in analyses adjusted for sociodemographics and tobacco dependence (p < .05). Greater vigilance was associated with greater attributions that health was affected by chance, which was associated with a lower likelihood of smoking abstinence. Conclusions Results suggest that neighborhood perceptions influence residents’ attributions for health outcomes, which can affect smoking abstinence. PMID:23985180

  17. Between-gender differences in vigilance do not necessarily lead to differences in foraging-vigilance tradeoffs.

    PubMed

    Barnier, Florian; Duncan, Patrick; Fritz, Hervé; Blanchard, Pierrick; Rubenstein, Daniel I; Pays, Olivier

    2016-07-01

    When prey are time limited in their access to food, any trade-off involving time should ultimately affect their intake rate. In many herbivores, males and females experience different ecological pressures affecting their survival and reproduction because of differences in morphology, physiology and energy/nutrient requirements. If males and females have different vigilance strategies that affect their intake rates differently, they will suffer different foraging costs. This is particularly relevant in sexually monomorphic herbivores, where the two sexes have similar basal energy/nutrient requirements and risk of predation. We investigated how gender, reproductive status, age, group size, predation risk, and food biomass affected vigilance, intake rate, and their trade-off in a monomorphic species, the plains zebra (Equus quagga). Males were more vigilant than females, and lactating females were less vigilant than other females; the levels of vigilance were low (ca. 10 % of feeding time). The effects on time spent feeding, bite rates and intake rates were small and statistically not significant. Reproductive status did not affect the strength of the relationship between vigilance and intake rate, but intake rates increased with group size and, for adult females, were higher in tall grass. While gender and reproductive status were major drivers of vigilance, and group size and food biomass of the rate of food intake, males and females adjust their bite rates and food intake with vigilance in similar ways. Our results support the hypothesis that in monomorphic animals, males and females seem to make similar trade-offs (i.e. adjustments) between vigilance and intake rate. PMID:27017605

  18. Warfarin and Drug Interactions: Prescribing Vigilance.

    PubMed

    Hook, J; Millsopp, Lynne; Field, E Anne

    2016-01-01

    A patient taking warfarin presented to the Oral Medicine Clinic at Liverpool University Dental Hospital, having been prescribed metronidazole and miconazole by his general dental practitioner (GDP) for his oral mucosal problem. He subsequently developed bruising on his torso following mild trauma. Having read the drug information leaflet provided with his metronidazole and miconazole, he noted the potential drug interactions between these and warfarin. He therefore stopped his warfarin. The details of this case are outlined, and the potential for significant drug interactions with warfarin are highlighted. The need for dental practitioners to be vigilant concerning drug interactions is emphasized, together with the importance of CPD in relation to drug prescribing. CPD/CLINICAL RELEVANCE: This case report, which is of relevance to all dental practitioners, highlights the importance of up-to-date medical and drug histories and the continuing awareness of potential drug interactions. In this case, patient intervention after checking drug information leaflets prevented serious consequences. The importance and potentially serious consequences of significant drug interactions needs to be understood. PMID:27024900

  19. [Research progress of methods for brain vigilance improvement].

    PubMed

    Zhu, Xianfeng; Liu, Yating; Zhang, Yi; Zhou, Peng; Wang, Mingshi

    2013-06-01

    Vigilance is defined as the ability to maintain attention or alertness over prolonged periods of time. Since Mid-20th century, following the increasing man-machine communication, high level of vigilance has been demanded in many areas including driving safety, medical care and therapy, aerospace and military affairs, etc. Therefore, finding quick methods to improve the level of vigilance has become a key issue in medical study. Based on physical regulation, chemical regulation and physiological regulation, the research progress has been summarized in this paper. We, furthermore, also try to predict the future trend in this academic area and develop some tentative ideas about seeking more effective and convenient ways to improve the level of brain vigilance. PMID:23865336

  20. THE RELATIONSHIPS AMONG VIGILANT COPING STYLE, RACE, AND DEPRESSION

    PubMed Central

    LaVeist, Thomas A.; Thorpe, Roland J.; Pierre, Geraldine; Mance, GiShawn A.; Williams, David R.

    2014-01-01

    Although Black-white differences in depression are well documented, vigilant coping style as an explanation for the observed inequalities in depression is less understood. Using data from 718 adults in the Exploring Health Disparities in Integrated Communities (EHDIC) Study, we estimated logistic regression models to examine the cross sectional relationship between race, vigilant coping style, and depression. After controlling for demographic variables, white adults were more likely to report depression than Black adults. Moreover, when accounting for coping style, the Black-white difference in depression widened. This association persisted even with the addition of the covariates. While high rates of depression among whites compared with Blacks are well documented, the degree of the differences appears to be greater than previously reported once vigilance is accounted for. This finding suggests that if it were not for the high prevalence of vigilant coping in blacks, the well-documented black advantage regarding depression compared to whites would likely be even greater. PMID:24954953

  1. Reinforcement Enhances Vigilance Among Children With ADHD: Comparisons to Typically Developing Children and to the Effects of Methylphenidate

    PubMed Central

    Bubnik, Michelle G.; Hawk, Larry W.; Pelham, William E.; Waxmonsky, James G.; Rosch, Keri S.

    2014-01-01

    Sustained attention and reinforcement are posited as causal mechanisms in Attention-Deficit/Hyperactivity Disorder (ADHD), but their interaction has received little empirical study. In two studies, we examined the impact of performance-based reinforcement on sustained attention over time, or vigilance, among 9- to 12-year-old children. Study 1 demonstrated the expected vigilance deficit among children with ADHD (n=25; 12% female) compared to typically developing (TD) controls (n=33; 22% female) on a standard continuous performance task (CPT). During a subsequent visit, reinforcement improved attention more among children with ADHD than controls. Study 2 examined the separate and combined effects of reinforcement and acute methylphenidate (MPH) on CPT performance in children with ADHD (n=19; 21% female). Both reinforcement and MPH enhanced overall target detection and attenuated the vigilance decrement that occurred in no-reinforcement, placebo condition. Cross-study comparisons suggested that the combination of MPH and reinforcement eliminated the vigilance deficit in children with ADHD, normalizing sustained attention. This work highlights the clinically and theoretically interesting intersection of reinforcement and sustained attention. PMID:24931776

  2. Slow brain oscillations of sleep, resting state, and vigilance.

    PubMed

    Van Someren, E J W; Van Der Werf, Y D; Roelfsema, P R; Mansvelder, H D; da Silva, F H Lopes

    2011-01-01

    The most important quest of cognitive neuroscience may be to unravel the mechanisms by which the brain selects, links, consolidates, and integrates new information into its neuronal network, while preventing saturation to occur. During the past decade, neuroscientists working within several disciplines have observed an important involvement of the specific types of brain oscillations that occur during sleep--the cortical slow oscillations; during the resting state--the fMRI resting state networks including the default-mode network (DMN); and during task performance--the performance modulations that link as well to modulations in electroencephalography or magnetoencephalography frequency content. Understanding the role of these slow oscillations thus appears to be essential for our fundamental understanding of brain function. Brain activity is characterized by oscillations occurring in spike frequency, field potentials or blood oxygen level-dependent functional magnetic resonance imaging signals. Environmental stimuli, reaching the brain through our senses, activate or inactivate neuronal populations and modulate ongoing activity. The effect they sort is to a large extent determined by the momentary state of the slow endogenous oscillations of the brain. In the absence of sensory input, as is the case during rest or sleep, brain activity does not cease. Rather, its oscillations continue and change with respect to their dominant frequencies and coupling topography. This chapter briefly introduces the topics that will be addressed in this dedicated volume of Progress in Brain Research on slow oscillations and sets the stage for excellent papers discussing their molecular, cellular, network physiological and cognitive performance aspects. Getting to know about slow oscillations is essential for our understanding of plasticity, memory, brain structure from synapse to DMN, cognition, consciousness, and ultimately for our understanding of the mechanisms and functions of

  3. Alcohol and Sleep Restriction Combined Reduces Vigilant Attention, Whereas Sleep Restriction Alone Enhances Distractibility

    PubMed Central

    Lee, James; Manousakis, Jessica; Fielding, Joanne; Anderson, Clare

    2015-01-01

    Study Objectives: Alcohol and sleep loss are leading causes of motor vehicle crashes, whereby attention failure is a core causal factor. Despite a plethora of data describing the effect of alcohol and sleep loss on vigilant attention, little is known about their effect on voluntary and involuntary visual attention processes. Design: Repeated-measures, counterbalanced design. Setting: Controlled laboratory setting. Participants: Sixteen young (18–27 y; M = 21.90 ± 0.60 y) healthy males. Interventions: Participants completed an attention test battery during the afternoon (13:00–14:00) under four counterbalanced conditions: (1) baseline; (2) alcohol (0.05% breath alcohol concentration); (3) sleep restriction (02:00–07:00); and (4) alcohol/sleep restriction combined. This test battery included a Psychomotor Vigilance Task (PVT) as a measure of vigilant attention, and two ocular motor tasks—visually guided and antisaccade—to measure the involuntary and voluntary allocation of visual attention. Measurements and Results: Only the combined condition led to reductions in vigilant attention characterized by slower mean reaction time, fastest 10% responses, and increased number of lapses (P < 0.05) on the PVT. In addition, the combined condition led to a slowing in the voluntary allocation of attention as reflected by increased antisaccade latencies (P < 0.05). Sleep restriction alone however increased both antisaccade inhibitory errors [45.8% errors versus < 28.4% all others; P < 0.001] and the involuntary allocation of attention, as reflected by faster visually guided latencies (177.7 msec versus > 185.0 msec all others) to a peripheral target (P < 0.05). Conclusions: Our data reveal specific signatures for sleep related attention failure: the voluntary allocation of attention is impaired, whereas the involuntary allocation of attention is enhanced. This provides key evidence for the role of distraction in attention failure during sleep loss. Citation: Lee J

  4. Vigilance in the discrimination-stress model for Black Americans

    PubMed Central

    Himmelstein, Mary S.; Young, Danielle M.; Sanchez, Diana T.; Jackson, James S.

    2015-01-01

    Objective Daily events of discrimination are important factors in understanding health disparities. Vigilant coping, or protecting against anticipated discrimination by monitoring and modifying behaviour, is an understudied mechanism that may link discrimination and health outcomes. This study investigates how responding to everyday discrimination with anticipatory vigilance relates to the health of Black men and women. Methods Black adults (N = 221) from the Detroit area completed measures of discrimination, adverse life events, vigilance coping, stress, depressive symptoms and self-reported health. Results Vigilance coping strategies mediated the relationship between discrimination and stress. Multi-group path analysis revealed that stress in turn was associated with increased depression in men and women. Self-reported health consequences of stress differed between men and women. Conclusions Vigilance coping mediates the link between discrimination and stress, and stress has consequences for health outcomes resulting from discrimination. More research is needed to understand other underlying contributors to discrimination, stress and poor health outcomes as well as to create potential interventions to ameliorate health outcomes in the face of discrimination-related stress. PMID:25247925

  5. Artificial light pollution increases nocturnal vigilance in peahens

    PubMed Central

    Chisholm, Sarah; Byerley, Sydney D; Coy, Jeanee R.; Aziz, Aisyah; Wolf, Jamie A.; Gnerlich, Amanda C.

    2015-01-01

    Artificial light pollution is drastically changing the sensory environments of animals. Even though many animals are now living in these changed environments, the effect light pollution has on animal behavior is poorly understood. We investigated the effect of light pollution on nocturnal vigilance in peahens (Pavo cristatus). Captive peahens were exposed to either artificial lighting or natural lighting at night. We employed a novel method to record their vigilance behavior by attaching accelerometers to their heads and continuously monitoring their large head movements. We found that light pollution significantly increases nocturnal vigilance in peahens. Furthermore, the birds faced a trade-off between vigilance and sleep at night: peahens that were more vigilant spent less time sleeping. Given the choice, peahens preferred to roost away from high levels of artificial lighting but showed no preference for roosting without artificial lighting or with low levels of artificial lighting. Our study demonstrates that light pollution can have a substantial impact on animal behavior that can potentially result in fitness consequences. PMID:26339552

  6. Validation of the Japanese Version of the Body Vigilance Scale.

    PubMed

    Saigo, Tatsuo; Takebayashi, Yoshitake; Tayama, Jun; Bernick, Peter J; Schmidt, Norman B; Shirabe, Susumu; Sakano, Yuji

    2016-06-01

    The Body Vigilance Scale is a self-report measure of attention to bodily sensations. The measure was translated into Japanese and its reliability, validity, and factor structure were verified. Participants comprised 286 university students (age: 19 ± 1 years). All participants were administered the scale, along with several indices of anxiety (i.e., Anxiety Sensitivity Index, Short Health Anxiety Inventory Illness Likelihood Scale, Social Interaction Anxiety Scale, and Hospital Anxiety and Depression Scale). The Japanese version of the Body Vigilance Scale exhibited a unidimensional factor structure and strong internal consistency. Construct validity was demonstrated by significant correlations with the above measures. Results suggest that the Japanese version of the scale is a reliable, valid tool for measuring body vigilance in Japanese university students. PMID:27207736

  7. Heart Rate Variability for Evaluating Vigilant Attention in Partial Chronic Sleep Restriction

    PubMed Central

    Henelius, Andreas; Sallinen, Mikael; Huotilainen, Minna; Müller, Kiti; Virkkala, Jussi; Puolamäki, Kai

    2014-01-01

    Study Objectives: Examine the use of spectral heart rate variability (HRV) metrics in measuring sleepiness under chronic partial sleep restriction, and identify underlying relationships between HRV, Karolinska Sleepiness Scale ratings (KSS), and performance on the Psychomotor Vigilance Task (PVT). Design: Controlled laboratory study. Setting: Experimental laboratory of the Brain Work Research Centre of the Finnish Institute of Occupational Health, Helsinki, Finland. Participants: Twenty-three healthy young males (mean age ± SD = 23.77 ± 2.29). Interventions: A sleep restriction group (N = 15) was subjected to chronic partial sleep restriction with 4 h sleep for 5 nights. A control group (N = 8) had 8 h sleep on all nights. Measurements and Results: Based on a search over all HRV frequency bands in the range [0.00, 0.40] Hz, the band [0.01, 0.08] Hz showed the highest correlation for HRV–PVT (0.60, 95% confidence interval [0.49, 0.69]) and HRV–KSS (0.33, 95% confidence interval [0.16, 0.46]) for the sleep restriction group; no correlation was found for the control group. We studied the fraction of variance in PVT explained by HRV and a 3-component alertness model, containing circadian and homeostatic processes coupled with sleep inertia, respectively. HRV alone explained 33% of PVT variance. Conclusions: The findings suggest that HRV spectral power reflects vigilant attention in subjects exposed to partial chronic sleep restriction. Citation: Henelius A, Sallinen M, Huotilainen M, Müller K, Virkkala J, Puolamäki K. Heart rate variability for evaluating vigilant attention in partial chronic sleep restriction. SLEEP 2014;37(7):1257-1267. PMID:24987165

  8. Classifying Vulnerability to Sleep Deprivation Using Baseline Measures of Psychomotor Vigilance

    PubMed Central

    Patanaik, Amiya; Kwoh, Chee Keong; Chua, Eric C.P.; Gooley, Joshua J.; Chee, Michael W.L.

    2015-01-01

    Objective: To identify measures derived from baseline psychomotor vigilance task (PVT) performance that can reliably predict vulnerability to sleep deprivation. Design: Subjects underwent total sleep deprivation and completed a 10-min PVT every 1–2 h in a controlled laboratory setting. Participants were categorized as vulnerable or resistant to sleep deprivation, based on a median split of lapses that occurred following sleep deprivation. Standard reaction time, drift diffusion model (DDM), and wavelet metrics were derived from PVT response times collected at baseline. A support vector machine model that incorporated maximum relevance and minimum redundancy feature selection and wrapper-based heuristics was used to classify subjects as vulnerable or resistant using rested data. Setting: Two academic sleep laboratories. Participants: Independent samples of 135 (69 women, age 18 to 25 y), and 45 (3 women, age 22 to 32 y) healthy adults. Measurements and Results: In both datasets, DDM measures, number of consecutive reaction times that differ by more than 250 ms, and two wavelet features were selected by the model as features predictive of vulnerability to sleep deprivation. Using the best set of features selected in each dataset, classification accuracy was 77% and 82% using fivefold stratified cross-validation, respectively. Conclusions: Despite differences in experimental conditions across studies, drift diffusion model parameters associated reliably with individual differences in performance during total sleep deprivation. These results demonstrate the utility of drift diffusion modeling of baseline performance in estimating vulnerability to psychomotor vigilance decline following sleep deprivation. Citation: Patanaik A, Kwoh CK, Chua EC, Gooley JJ, Chee MW. Classifying vulnerability to sleep deprivation using baseline measures of psychomotor vigilance. SLEEP 2015;38(5):723–734. PMID:25325482

  9. Dose-response relationship between sleep duration and human psychomotor vigilance and subjective alertness

    NASA Technical Reports Server (NTRS)

    Jewett, M. E.; Dijk, D. J.; Kronauer, R. E.; Dinges, D. F.

    1999-01-01

    Although it has been well documented that sleep is required for human performance and alertness to recover from low levels after prolonged periods of wakefulness, it remains unclear whether they increase in a linear or asymptotic manner during sleep. It has been postulated that there is a relation between the rate of improvement in neurobehavioral functioning and rate of decline of slow-wave sleep and/or slow-wave activity (SWS/SWA) during sleep, but this has not been verified. Thus, a cross-study comparison was conducted in which dose-response curves (DRCs) were constructed for Stanford Sleepiness Scale (SSS) and Psychomotor Vigilance Task (PVT) tests taken at 1000 hours by subjects who had been allowed to sleep 0 hours, 2 hours, 5 hours or 8 hours the previous night. We found that the DRCs to each PVT metric improved in a saturating exponential manner, with recovery rates that were similar [time constant (T) approximately 2.14 hours] for all the metrics. This recovery rate was slightly faster than, though not statistically significantly different from, the reported rate of SWS/SWA decline (T approximately 2.7 hours). The DRC to the SSS improved much more slowly than psychomotor vigilance, so that it could be fit equally well by a linear function (slope = -0.26) or a saturating exponential function (T = 9.09 hours). We conclude that although SWS/SWA, subjective alertness, and a wide variety of psychomotor vigilance metrics may all change asymptotically during sleep, it remains to be determined whether the underlying physiologic processes governing their expression are different.

  10. Motivation in vigilance - A test of the goal-setting hypothesis of the effectiveness of knowledge of results.

    NASA Technical Reports Server (NTRS)

    Warm, J. S.; Riechmann, S. W.; Grasha, A. F.; Seibel, B.

    1973-01-01

    This study tested the prediction, derived from the goal-setting hypothesis, that the facilitating effects of knowledge of results (KR) in a simple vigilance task should be related directly to the level of the performance standard used to regulate KR. Two groups of Ss received dichotomous KR in terms of whether Ss response times (RTs) to signal detections exceeded a high or low standard of performance. The aperiodic offset of a visual signal was the critical event for detection. The vigil was divided into a training phase followed by testing, during which KR was withdrawn. Knowledge of results enhanced performance in both phases. However, the two standards used to regulate feedback contributed little to these effects.

  11. Interactions among social monitoring, anti-predator vigilance and group size in eastern grey kangaroos

    PubMed Central

    Favreau, François-René; Goldizen, Anne W.; Pays, Olivier

    2010-01-01

    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. PMID:20219737

  12. Vigilance adjustments in relation to long- and short term risk in wild fallow deer (Dama dama).

    PubMed

    Bergvall, Ulrika A; Svensson, Lisa; Kjellander, Petter

    2016-07-01

    The risk allocation hypothesis predicts that vigilance should be adjusted to the temporal variation in risk. We test this hypothesis in wild fallow deer exposed to short term (disturbance) and long term (presence of a fawn after parturition) changes in risk. We recorded the proportion, frequency and type of vigilance and size of used area before and after parturition, in GPS-collared wild female fallow deer. Vigilance was divided in two main groups: "non-grazing vigilance" and "grazing vigilance". The latter group was divided into "grazing vigilance while chewing" and a "grazing vigilance when chewing was interrupted". By recording external disturbance in form of passing cars, we were able to investigate if this altered the amount, and type of vigilance. We found that females increased the proportion and frequency of "grazing vigilance stop chewing" after parturition. The "grazing vigilance chewing" was unaffected, but "non-grazing vigilance" decreased. Disturbance increased the proportion "grazing vigilance stop chewing" to the same extent before and after parturition. We found a clear decrease in female home range size after parturition as a possible behavioural adjustment. The increase in "grazing vigilance stop chewing" after parturition is a rarely described but expected cost of reproduction. PMID:27094230

  13. Real-time performance modelling of a Sustained Attention to Response Task.

    PubMed

    Larue, Grégoire S; Rakotonirainy, Andry; Pettitt, Anthony N

    2010-10-01

    Vigilance declines when exposed to highly predictable and uneventful tasks. Monotonous tasks provide little cognitive and motor stimulation and contribute to human errors. This paper aims to model and detect vigilance decline in real time through participants' reaction times during a monotonous task. A laboratory-based experiment adapting the Sustained Attention to Response Task (SART) is conducted to quantify the effect of monotony on overall performance. Relevant parameters are then used to build a model detecting hypovigilance throughout the experiment. The accuracy of different mathematical models is compared to detect in real time - minute by minute - the lapses in vigilance during the task. It is shown that monotonous tasks can lead to an average decline in performance of 45%. Furthermore, vigilance modelling enables the detection of vigilance decline through reaction times with an accuracy of 72% and a 29% false alarm rate. Bayesian models are identified as a better model to detect lapses in vigilance as compared with neural networks and generalised linear mixed models. This modelling could be used as a framework to detect vigilance decline of any human performing monotonous tasks. STATEMENT OF RELEVANCE: Existing research on monotony is largely entangled with endogenous factors such as sleep deprivation, fatigue and circadian rhythm. This paper uses a Bayesian model to assess the effects of a monotonous task on vigilance in real time. It is shown that the negative effects of monotony on the ability to sustain attention can be mathematically modelled and predicted in real time using surrogate measures, such as reaction times. This allows the modelling of vigilance fluctuations. PMID:20865604

  14. Teaching Blended Content Analysis and Critically Vigilant Media Consumption

    ERIC Educational Resources Information Center

    Harris, Christopher S.

    2015-01-01

    The semester-long activity described herein uses an integrated instructional approach to media studies to introduce students to the research method of qualitative content analysis and help them become more critically vigilant media consumers. The goal is to increase students' media literacy by guiding them in the design of an exploratory…

  15. LACK OF EFFECTS OF CARBON MONOXIDE ON HUMAN VIGILANCE

    EPA Science Inventory

    Previous publications on the effects of low levels of carbon monoxide (CO) on human vigilance performance have found conflicting results. While several studies have found statistically reliable effects, none have gone unchallenged. This article presents a critical review of the l...

  16. Detrimental effects of gum chewing on vigilance in children with attention deficit hyperactivity disorder.

    PubMed

    Tucha, Lara; Simpson, William; Evans, Lynsay; Birrel, Laura; Sontag, Thomas A; Lange, Klaus W; Tucha, Oliver

    2010-12-01

    Impairments of attention are cardinal features of attention deficit hyperactivity disorder (ADHD) and can seriously affect the daily life of children with ADHD. Despite effective treatment strategies, there is a need of further treatment options that can be added to available and well established treatments. Further treatment options are needed since available treatments are often time consuming, expensive and limited regarding their external validity. Recent research demonstrated that gum chewing has beneficial effects on cognition including certain aspects of attention. Therefore, gum chewing may benefit children with ADHD in situations requiring particular cognitive efforts. In a crossover study, attentional functioning of 32 children with ADHD and 32 children without the condition was examined. All participants were assessed with chewing gum and without chewing gum. A computerized test was used for the assessment of vigilance and sustained attention. The findings of the present study suggest that gum chewing during task execution has detrimental effects on vigilance of both healthy children and children with ADHD. Sustained attention was not affected by gum chewing. Chewing gum, therefore, appears not to improve attentional performance in children with ADHD. PMID:20933558

  17. Poor vigilance affects attentional orienting triggered by central uninformative gaze and arrow cues.

    PubMed

    Marotta, Andrea; Martella, Diana; Maccari, Lisa; Sebastiani, Mara; Casagrande, Maria

    2014-11-01

    Behaviour and neuroimaging studies have shown that poor vigilance (PV) due to sleep deprivation (SD) negatively affects exogenously cued selective attention. In the current study, we assessed the impact of PV due to both partial SD and night-time hours on reflexive attentional orienting triggered by central un-informative eye-gaze and arrow cues. Subjective mood and interference performance in emotional Stroop task were also investigated. Twenty healthy participants performed spatial cueing tasks using central directional arrow and eye-gaze as a cue to orient attention. The target was a word written in different coloured inks. The participant's task was to identify the colour of the ink while ignoring the semantic content of the word (with negative or neutral emotional valence). The experiment took place on 2 days. On the first day, each participant performed a 10-min training session of the spatial cueing task. On the second day, half of participants performed the task once at 4:30 p.m. (BSL) and once at 6:30 a.m. (PV), whereas the other half performed the task in the reversed order. Results showed that mean reaction times on the spatial cueing tasks were worsened by PV, although gaze paradigm was more resistant to this effect as compared to the arrow paradigm. Moreover, PV negatively affects attentional orienting triggered by both central un-informative gaze and arrow cues. Finally, prolonged wakefulness affects self-reported mood but does not influence interference control in emotional Stroop task. PMID:24718933

  18. White-tailed deer vigilance: the influence of social and environmental factors.

    PubMed

    Lashley, Marcus A; Chitwood, M Colter; Biggerstaff, Michael T; Morina, Daniel L; Moorman, Christopher E; DePerno, Christopher S

    2014-01-01

    Vigilance behavior may directly affect fitness of prey animals, and understanding factors influencing vigilance may provide important insight into predator-prey interactions. We used 40,540 pictures taken withcamera traps in August 2011 and 2012to evaluate factors influencing individual vigilance behavior of white-tailed deer (Odocoileus virginianus) while foraging at baited sites. We used binary logistic regression to determine if individual vigilance was affected by age, sex, and group size. Additionally, we evaluated whether the time of the day,moon phase,and presence of other non-predatorwildlife species impacted individual vigilance. Juveniles were 11% less vigilant at baited sites than adults. Females were 46% more vigilant when fawns were present. Males and females spent more time feeding as group size increased, but with each addition of 1 individual to a group, males increased feeding time by nearly double that of females. Individual vigilance fluctuated with time of day andwith moon phase but generally was least during diurnal and moonlit nocturnal hours, indicating deer have the ability to adjust vigilance behavior to changing predation risk associated with varyinglight intensity.White-tailed deer increased individual vigilance when other non-predator wildlife were present. Our data indicate that differential effects of environmental and social constraints on vigilance behavior between sexes may encourage sexual segregation in white-tailed deer. PMID:24599090

  19. [Influence of pedagogy on vigilance in school age children].

    PubMed

    Zaczyk-Martin, C; Nuttens, M C; Hautekeete, M; Salomez, J L; Lequien, P

    1990-01-01

    The relationship between vigilance and pedagogy was studied in 3 middle classes of primary school (children aged between 8 and 9 yrs). Three different types of pedagogy, belonging to 3 major pedagogic currents were evaluated: the pedagogy of Maria Montessori, the traditional one and the so-called "open" pedagogy. The vigilance of children was tested with the psychometric test of Zazzo. The rate of performance of the test was significantly different according to the nature of pedagogy after adjustment of the only 2 confusing factors between the 3 schools: the age of the children and the degree of the mother. This difference was in favor of the pedagogy of Maria Montessori compared with the 2 others. It was observed on the results to the tests but also on learning. PMID:2170913

  20. Coordination and synchronisation of anti-predation vigilance in two crane species.

    PubMed

    Ge, Chen; Beauchamp, Guy; Li, Zhongqiu

    2011-01-01

    Much of the previous research on anti-predation vigilance in groups has assumed independent scanning for threats among group members. Alternative patterns that are based on monitoring the vigilance levels of companions can also be adaptive. Coordination of vigilance, in which foragers avoid scanning at the same time as others, should decrease the odds that no group member is alert. Synchronisation of vigilance implies that individuals are more likely to be vigilant when companions are already vigilant. While synchronisation will increase the odds that no one is vigilant, it may allow a better assessment of potential threats. We investigated temporal sequences of vigilance in family flocks consisting of two parents and at most two juveniles in two species of cranes in coastal China. We established whether the observed probability that at least one parent is alert was greater (coordination) or lower (synchronisation) than that predicted under the null hypothesis of independent vigilance. We documented coordination of vigilance in common cranes (Grus grus) foraging in an area with high potential for disturbance by people. We documented synchronisation of vigilance in red-crowned cranes (Grus japonensis) in the less but not in the more disturbed area. Coordination in small flocks leads to high collective vigilance but low foraging rates that may not be suitable in areas with low disturbance. We also argue that synchronisation should break down in areas with high disturbance because periods with low vigilance are riskier. Results highlight the view that temporal patterns of vigilance can take many forms depending on ecological factors. PMID:22028880

  1. Impaired conflict resolution and vigilance in euthymic bipolar disorder.

    PubMed

    Marotta, Andrea; Chiaie, Roberto Delle; Spagna, Alfredo; Bernabei, Laura; Sciarretta, Martina; Roca, Javier; Biondi, Massimo; Casagrande, Maria

    2015-09-30

    Difficulty attending is a common deficit of euthymic bipolar patients. However, it is not known whether this is a global attentional deficit or relates to a specific attentional network. According to the attention network approach, attention is best understood in terms of three functionally and neuroanatomically distinct networks-alerting, orienting, and executive control. In this study, we explored whether and which of the three attentional networks are altered in euthymic Bipolar Disorder (BD). A sample of euthymic BD patients and age-matched healthy controls completed the Attention Network Test for Interactions and Vigilance (ANTI-V) that provided not only a measure of orienting, executive, and alerting networks, but also an independent measure of vigilance (tonic alerting). Compared to healthy controls, BD patients have impaired executive control (greater interference), reduced vigilance (as indexed by a decrease in the d' sensitivity) as well as slower overall reaction times and poorer accuracy. Our results show that deficits in executive attention and sustained attention often persist in BD patients even after complete remission of affective symptoms, thus suggesting that cognitive enhancing treatments programmed to improve these deficits could contribute to improve their functional recovery. PMID:26144587

  2. Evolutionary stability of vigilance coordination among social foragers.

    PubMed Central

    Rodríguez-Gironés, Miguel A; Vásquez, Rodrigo A

    2002-01-01

    Coordination can greatly improve the efficiency of anti-predatory vigilance scans by increasing predator detection for a constant proportion of time spent vigilant. However, it has been rarely found in nature and most studies have detected or assumed independent scanning by group members. In this study, we analysed the functional consequences of the coordinated alternation of vigilance scanning by group foragers. We introduce coordination by assuming that interscan intervals (ISIs) follow a modified gamma distribution. Depending on the parameters of the distribution, successive scans can be evenly spaced (coordinated scanning) or may present a high overlap (uncoordinated scanning). Comparing evolutionarily stable strategies for animals that do not coordinate their scanning with animals that do coordinate their anti-predator behaviour shows that coordination has a marked effect on survival probability. Moreover, the coordinating strategy is quite robust against mutants that scan independently with exponential distributions of ISIs. However, coordination breaks down when animals can continuously adjust their level of coordination by deciding the proportion of time they spend monitoring the behaviour of other group members. In this case, coordination is only evolutionarily stable if it can be very easily achieved. PMID:12350268

  3. Measures and Interpretations of Vigilance Performance: Evidence Against the Detection Criterion

    NASA Technical Reports Server (NTRS)

    Balakrishnan, J. D.

    1998-01-01

    Operators' performance in a vigilance task is often assumed to depend on their choice of a detection criterion. When the signal rate is low this criterion is set high, causing the hit and false alarm rates to be low. With increasing time on task the criterion presumably tends to increase even further, thereby further decreasing the hit and false alarm rates. Virtually all of the empirical evidence for this simple interpretation is based on estimates of the bias measure Beta from signal detection theory. In this article, I describe a new approach to studying decision making that does not require the technical assumptions of signal detection theory. The results of this new analysis suggest that the detection criterion is never biased toward either response, even when the signal rate is low and the time on task is long. Two modifications of the signal detection theory framework are considered to account for this seemingly paradoxical result. The first assumes that the signal rate affects the relative sizes of the variances of the information distributions; the second assumes that the signal rate affects the logic of the operator's stopping rule. Actual or potential applications of this research include the improved training and performance assessment of operators in areas such as product quality control, air traffic control, and medical and clinical diagnosis.

  4. Influence of the composition of a meal taken after physical exercise on mood, vigilance, performance.

    PubMed

    Verger, P; Lagarde, D; Batejat, D; Maitre, J F

    1998-06-01

    The metabolic and behavioral effects of nutrients after exercise on vigilance level, performance, and mood have been minimally studied and have given contradictory results. In order to increase the understanding of the relationships between nutrition, exercise and performance, this experiment compared the effects on mood and performance of a protein- rich meal and a protein- poor meal, eaten just after an acute session of exercise. Vigilance and mood were evaluated by visual analog scales, and memory was measured by memory search task from the AGARD STRES battery, based on the Sternberg paradigm. Forty-two subjects were involved in this experiment. All subjects participated in the study of the effect of exercise after two kinds of meals (protein and nonprotein). Two groups of fourteen subjects we used to evaluate the effect of the exercise and the effect of the delay of meal intake after exercise in the two kinds of diet. The results show no difference in memory performance between exercise and rest conditions, nor between "protein" and "no protein" meal groups. They do show, however, that subjects feel happier after a meal with protein than after a meal without protein. The effects of the "no protein" meal on drowsiness differ with the glucide content of the meal. Subjects are less drowsy when they eat between 125 and 150 g of glucide than when they eat more than 150 g. The rousing effect induced by physical exercise is counterbalanced when subjects eat more than 150 g of carbohydrate. The anxiolytic effect of glucide is re-established. PMID:9748099

  5. A novel mechanism for a survival advantage of vigilant individuals in groups.

    PubMed

    van der Post, Daniel J; de Weerd, Harmen; Verbrugge, Rineke; Hemelrijk, Charlotte K

    2013-11-01

    In many animal species, vigilance is crucial for avoiding predation. In groups, however, nonvigilant individuals could benefit from the vigilance of others without any of the associated costs. In an evolutionary sense, such exploitation may be compensated if vigilant individuals have a survival advantage. The novelty in our model is that the probability to detect a predator is "distance dependent." We show that even if nonvigilant individuals benefit fully from information produced by vigilant individuals, vigilant individuals nevertheless enjoy a survival advantage. This happens because detection of predators is more likely when vigilant individuals happen to be targets of predation. We expect this distance-dependent mechanism to be compatible with previously reported mechanisms. PMID:24107375

  6. Vigilance and feeding behaviour in large feeding flocks of laughing gulls, Larus atricilla, on Delaware Bay

    NASA Astrophysics Data System (ADS)

    Burger, Joanna; Gochfeld, Michael

    1991-02-01

    Laughing gulls ( Larus atricilla) forage on horseshoe crab ( Limulus polyphemus) eggs during May in Delaware Bay each year. They feed in dense flocks, and foraging rates vary with vigilance, bird density, number of steps and location in the flock, whereas time devoted to vigilance is explained by number of steps, density, location and feeding rates. The time devoted to vigilance decreases with increasing density, increasing foraging rates and decreasing aggression. Birds foraging on the edge of flocks take fewer pecks and more steps, and devote more time to vigilance than those in the intermediate or central parts of a flock.

  7. The effects of nicotine dose expectancy and motivationally relevant distracters on vigilance.

    PubMed

    Robinson, Jason D; Engelmann, Jeffery M; Cui, Yong; Versace, Francesco; Waters, Andrew J; Gilbert, David G; Gritz, Ellen R; Cinciripini, Paul M

    2014-09-01

    The imminence of drug use (i.e., drug availability) has been found to be related to intensity of drug craving, but its effects on attentional bias to drug cues are unclear. This study investigated the effects of nicotine availability on attentional bias to smoking, affective, and neutral cues in a sample of adult smokers during a vigilance task. At the beginning of each of 4 laboratory sessions, overnight nicotine-deprived smokers (n = 51) were instructed that they would smoke a cigarette containing either nicotine (Told-NIC) or no nicotine (Told-DENIC) after completing the rapid visual information processing task with central emotional distracters (RVIP-CED). The RVIP-CED presented digits at a rapid pace, with participants instructed to respond with button presses to every third consecutive even or odd digit. Some digits were preceded by smoking, pleasant, unpleasant, or neutral distracter slides. During Told-NIC conditions, participants produced significantly longer reaction time (RT) latency than during Told-DENIC conditions. RT sensitivity (d'), a measure of the ability to discriminate true positives from false positives, was significantly lower during the Told-NIC than during the Told-DENIC conditions to targets following cigarette distracters. These results suggest that nicotine-deprived smokers expecting to imminently smoke a cigarette experience greater distraction, particularly to smoking-related stimuli, than when expecting to smoke a denicotinized cigarette. PMID:24841184

  8. Cutting stress off at the pass: reducing vigilance and responsiveness to social threat by manipulating attention.

    PubMed

    Dandeneau, Stéphane D; Baldwin, Mark W; Baccus, Jodene R; Sakellaropoulo, Maya; Pruessner, Jens C

    2007-10-01

    Personality processes relating to social perception have been shown to play a significant role in the experience of stress. In 5 studies, the authors demonstrate that early stage attentional processes influence the perception of social threat and modify the human stress response. The authors first show that cortisol release in response to a stressful situation correlates with selective attention toward social threat. Second, the authors show in 2 laboratory studies that this attentional pattern, most evident among individuals with low self-esteem, can be modified with a repetitive training task. Next, in a field study, students trained to modify their attentional pattern to reduce vigilance for social threat showed lower self-reported stress related to their final exam. In a final field study with telemarketers, the attentional training task led to increased self-esteem, decreased cortisol and perceived stress responses, higher confidence, and greater work performance. Taken together, these results demonstrate the impact of antecedent-focused strategies on the late-stage consequences of social stress. PMID:17892337

  9. Sleep and vigilance linked to melanism in wild barn owls.

    PubMed

    Scriba, M F; Rattenborg, N C; Dreiss, A N; Vyssotski, A L; Roulin, A

    2014-10-01

    Understanding the function of variation in sleep requires studies in the natural ecological conditions in which sleep evolved. Sleep has an impact on individual performance and hence may integrate the costs and benefits of investing in processes that are sensitive to sleep, such as immunity or coping with stress. Because dark and pale melanic animals differentially regulate energy homeostasis, immunity and stress hormone levels, the amount and/or organization of sleep may covary with melanin-based colour. We show here that wild, cross-fostered nestling barn owls (Tyto alba) born from mothers displaying more black spots had shorter non-REM (rapid eye movement) sleep bouts, a shorter latency until the occurrence of REM sleep after a bout of wakefulness and more wakefulness bouts. In male nestlings, the same sleep traits also correlated with their own level of spotting. Because heavily spotted male nestlings and the offspring of heavily spotted biological mothers switched sleep-wakefulness states more frequently, we propose the hypothesis that they could be also behaviourally more vigilant. Accordingly, nestlings from mothers displaying many black spots looked more often towards the nest entrance where their parents bring food and towards their sibling against whom they compete. Owlets from heavily spotted mothers might invest more in vigilance, thereby possibly increasing associated costs due to sleep fragmentation. We conclude that different strategies of the regulation of brain activity have evolved and are correlated with melanin-based coloration. PMID:25056556

  10. Fitness for duty: A 3 minute version of the Psychomotor Vigilance Test predicts fatigue related declines in luggage screening performance

    PubMed Central

    Basner, Mathias; Rubinstein, Joshua

    2011-01-01

    Objective To evaluate the ability of a 3-min Psychomotor Vigilance Test (PVT) to predict fatigue related performance decrements on a simulated luggage screening task (SLST). Methods Thirty-six healthy non-professional subjects (mean age 30.8 years, 20 female) participated in a 4 day laboratory protocol including a 34 hour period of total sleep deprivation with PVT and SLST testing every 2 hours. Results Eleven and 20 lapses (355 ms threshold) on the PVT optimally divided SLST performance into high, medium, and low performance bouts with significantly decreasing threat detection performance A′. Assignment to the different SLST performance groups replicated homeostatic and circadian patterns during total sleep deprivation. Conclusions The 3 min PVT was able to predict performance on a simulated luggage screening task. Fitness-for-duty feasibility should now be tested in professional screeners and operational environments. PMID:21912278

  11. Nocturnal Hypoxia Exposure With Simulated Altitude For 14 Days Does Not Significantly Alter Working Memory or Vigilance in Humans

    PubMed Central

    Thomas, Robert Joseph; Tamisier, Renaud; Boucher, Judith; Kotlar, Yana; Vigneault, Kevin; Weiss, J. Woodrow; Gilmartin, Geoffrey

    2007-01-01

    Study Objectives: To assess the effect of 2 weeks of nocturnal hypoxia exposure using simulated altitude on attention and working memory in healthy adult humans. Design: Prospective experimental physiological assessment. Setting: General Clinical Research Center. Participants: Eleven healthy, nonsmoking, subjects (7 men, 4 women). The subjects had a mean age of 27 ± 1.5 years and body mass index of 23 ± 0.9 kg/m2 Interventions: Subjects were exposed to 9 hours of continuous hypoxia from 2200 to 0700 hours in an altitude tent. Acclimatization was accomplished by graded increases in “altitude” over 3 nights (7700, 10,000 and 13,000 feet), followed by 13,000 feet for 13 consecutive days (FIO2 0.13). Measurements and Results: Polysomnography that included airflow measurements with a nasal cannula were done at baseline and during 3 time points across the protocol (nights 3, 7, and 14). Attention (10-minute Psychomotor Vigilance Task) and working memory (10-minute verbal 2-back) were assessed at baseline and on day 4, 8, 9, and 15. Nocturnal hypoxia was documented using endpoints of minimum oxygen saturation, oxygen desaturation index, and percentage of total sleep time under 90% and 80%. Total sleep time was reduced, stage 1 sleep was increased, and both obstructive and nonobstructive respiratory events were induced by altitude exposure. There was no difference in subjective mood, attention, or working memory. Conclusions: Two weeks of nocturnal continuous hypoxia in an altitude tent did not induce subjective sleepiness or impair objective vigilance and working memory. Caution is recommended in the extrapolation to humans the effects of hypoxia in animal models. Citation: Thomas RJ; Ramisier R; Boucher J; Kotlar Y; Vigneault K; Weiss JW; Gilmartin G. Nocternal hypoxia exposure with simulated altitude for 14 days does not significantly alter working memory or vigilance in humans. SLEEP 2007;30(9):1195-1203. PMID:17910391

  12. Vigilance of kit foxes at water sources: a test of competing hypotheses for a solitary carnivore subject to predation.

    PubMed

    Hall, Lucas K; Day, Casey C; Westover, Matthew D; Edgel, Robert J; Larsen, Randy T; Knight, Robert N; McMillan, Brock R

    2013-03-01

    Animals that are potential prey do not respond equally to direct and indirect cues related to risk of predation. Based on differential responses to cues, three hypotheses have been proposed to explain spatial variation in vigilance behavior. The predator-vigilance hypothesis proposes that prey increase vigilance where there is evidence of predators. The visibility-vigilance hypothesis suggests that prey increase vigilance where visibility is obstructed. Alternatively, the refuge-vigilance hypothesis proposes that prey may perceive areas with low visibility (greater cover) as refuges and decrease vigilance. We evaluated support for these hypotheses using the kit fox (Vulpes macrotis), a solitary carnivore subject to intraguild predation, as a model. From 2010 to 2012, we used infrared-triggered cameras to record video of kit fox behavior at water sources in Utah, USA. The refuge-vigilance hypothesis explained more variation in vigilance behavior of kit foxes than the other two hypotheses (AICc model weight=0.37). Kit foxes were less vigilant at water sources with low overhead cover (refuge) obstructing visibility. Based on our results, the predator-vigilance and visibility-vigilance hypotheses may not be applicable to all species of prey. Solitary prey, unlike gregarious prey, may use areas with concealing cover to maximize resource acquisition and minimize vigilance. PMID:23305800

  13. In Search of Vigilance: The Problem of Iatrogenically Created Psychological Phenomena

    ERIC Educational Resources Information Center

    Hancock, P. A.

    2013-01-01

    To what extent are identified psychological processes created in laboratories? The present work addresses this issue with reference to one particular realm of behavior: vigilance. Specifically, I argue that the classic vigilance decrement function can be viewed more realistically and advantageously as an "invigilant" increment function. Rather…

  14. Attention/Vigilance in Schizophrenia: Performance Results from a Large Multi-Site Study of the Consortium on the Genetics of Schizophrenia (COGS)

    PubMed Central

    Nuechterlein, Keith H.; Green, Michael F.; Calkins, Monica E.; Greenwood, Tiffany A.; Gur, Raquel E.; Gur, Ruben C.; Lazzeroni, Laura C.; Light, Gregory A.; Radant, Allen D.; Seidman, Larry J.; Siever, Larry J.; Silverman, Jeremy M.; Sprock, Joyce; Stone, William S.; Sugar, Catherine A.; Swerdlow, Neal R.; Tsuang, Debby W.; Tsuang, Ming T.; Turetsky, Bruce I.; Braff, David L.

    2015-01-01

    Attention/vigilance impairments are present in individuals with schizophrenia across psychotic and remitted states and in their first-degree relatives. An important question is whether deficits in attention/vigilance can be consistently and reliably measured across sites varying in many participant demographic, clinical, and functional characteristics, as needed for large-scale genetic studies of endophenotypes. We examined Continuous Performance Test (CPT) data from Phase 2 of the Consortium on the Genetics of Schizophrenia (COGS-2), the largest-scale assessment of cognitive and psychophysiological endophenotypes relevant to schizophrenia. CPT data from 2251 participants from five sites were examined. A perceptual-load vigilance task (the Degraded Stimulus CPT or DS-CPT) and a memory-load vigilance task (CPT - Identical Pairs or CPT-IP) were utilized. Schizophrenia patients performed more poorly than healthy comparison subjects (HCS) across sites, despite significant site differences in participant age, sex, education, and racial distribution. Patient-HCS differences in signal/noise discrimination (d’) in the DS-CPT varied significantly across sites, but averaged a medium effect size. CPT-IP performance showed large patient-HCS differences across sites. Poor CPT performance was independent of or weakly correlated with symptom severity, but was significantly associated with lower educational achievement and functional capacity. Current smoking was associated with poorer CPT-IP d’. Patients taking both atypical and typical antipsychotic medication performed more poorly than those on no or atypical antipsychotic medications, likely reflecting their greater severity of illness. We conclude that CPT deficits in schizophrenia can be reliably detected across sites, are relatively independent of current symptom severity, and are related to functional capacity. PMID:25749017

  15. EDI system definition for a European medical device vigilance system.

    PubMed

    Doukidis, G; Pallikarakis, N; Pangalos, G; Vassilacopoulos, G; Pramataris, K

    1996-01-01

    EDI is expected to be the dominant form of business communication between organizations moving to the Electronic Commerce era of 2000. The healthcare sector is already using EDI in the hospital supply function as well as in the clinical area and the reimbursement process. In this paper, we examine the use of EDI in the healthcare administration sector and more specifically its application to the Medical Device Vigilance System. Firstly, the potential of this approach is examined, followed by the definition of the EDI System Reference Model and the specification of the required system architecture. Each of the architecture's components are then explained in more detail, followed by the most important implementation options relating to them. PMID:9062886

  16. Relapsing Fever: Diagnosis Thanks to a Vigilant Hematology Laboratory.

    PubMed

    Fuchs, Inbal; Tarabin, Salman; Kafka, Michael

    2015-07-01

    Three cases of relapsing fever from southern Israel were diagnosed promptly thanks to vigilance of the hematology laboratory technicians. In this region of Israel, patients presenting with prolonged fever and leukopenia without localizing symptoms are generally suspected of having brucellosis or a rickettsial disease. Pediatric patients with prolonged fever, cytopenias, and negative aforementioned serologies are often hospitalized for further work-up. Because of the policy of performing a manual blood smear when results of the automated blood count demonstrate severe anemia and abnormal platelet and/or white blood cell counts, a diagnosis of tick-borne relapsing fever was confirmed and promptly relayed to the physician. This routine prevented unnecessary examinations and hospitalization days and provided important information to regional epidemiology and public health authorities. PMID:26186517

  17. From vigilance to violence: mate retention tactics in married couples.

    PubMed

    Buss, D M; Shackelford, T K

    1997-02-01

    Although much research has explored the adaptive problems of mate selection and mate attraction, little research has investigated the adaptive problem of mate retention. We tested several evolutionary psychological hypotheses about the determinants of mate retention in 214 married people. We assessed the usage of 19 mate retention tactics ranging from vigilance to violence. Key hypothesized findings include the following: Men's, but not women's, mate retention positively covaried with partner's youth and physical attractiveness. Women's, but not men's, mate retention positively covaried with partner's income and status striving. Men's mate retention positively covaried with perceived probability of partner's infidelity. Men, more than women, reported using resource display, submission and debasement, and intrasexual threats to retain their mates. Women, more than men, reported using appearance enhancement and verbal signals of possession. Discussion includes an evolutionary psychological analysis of mate retention in married couples. PMID:9107005

  18. The Effects of Social Anxiety and State Anxiety on Visual Attention: Testing the Vigilance-Avoidance Hypothesis.

    PubMed

    Singh, J Suzanne; Capozzoli, Michelle C; Dodd, Michael D; Hope, Debra A

    2015-01-01

    A growing theoretical and research literature suggests that trait and state social anxiety can predict attentional patterns in the presence of emotional stimuli. The current study adds to this literature by examining the effects of state anxiety on visual attention and testing the vigilance-avoidance hypothesis, using a method of continuous visual attentional assessment. Participants were 91 undergraduate college students with high or low trait fear of negative evaluation (FNE), a core aspect of social anxiety, who were randomly assigned to either a high or low state anxiety condition. Participants engaged in a free view task in which pairs of emotional facial stimuli were presented and eye movements were continuously monitored. Overall, participants with high FNE avoided angry stimuli and participants with high state anxiety attended to positive stimuli. Participants with high state anxiety and high FNE were avoidant of angry faces, whereas participants with low state and low FNE exhibited a bias toward angry faces. The study provided partial support for the vigilance-avoidance hypothesis. The findings add to the mixed results in the literature that suggest that both positive and negative emotional stimuli may be important in understanding the complex attention patterns associated with social anxiety. Clinical implications and suggestions for future research are discussed. PMID:25767901

  19. Distinct pro-vigilant profile induced in rats by the mGluR5 potentiator LSN2814617.

    PubMed

    Loomis, Sally; McCarthy, Andrew; Baxter, Christopher; Kellett, Daniel O; Edgar, Dale M; Tricklebank, Mark; Gilmour, Gary

    2015-11-01

    While treatment options are available, excessive daytime sleepiness (EDS) remains a significant unmet medical need for many patients. Relatively little rodent behavioural pharmacology has been conducted in this context to assess potential pro-vigilant compounds for their ability to restore functional capacity following experimentally induced sleep loss. Male Wistar rats were prepared for electroencephalographic (EEG) recording and subject to 11 h of sleep restriction using a biofeedback-induced cage rotation protocol. A simple response latency task (SRLT) was used to behaviourally index sleep restriction and the effects of pro-vigilant compounds: modafinil, D-amphetamine, caffeine, and the mGlu5-positive allosteric modulator LSN2814617. Sleep restriction resulted in a consistent, quantified loss of non-rapid eye movement (NREM) and REM sleep that impaired SRLT performance in a manner suggestive of progressive task disengagement. In terms of EEG parameters, all compounds induced wakefulness. Amphetamine treatment further decreased SRLT performance capacity, whereas the other three compounds decreased omissions and allowed animals to re-engage in the task. Caffeine and modafinil also significantly increased premature responses during this period, an effect not observed for LSN2814617. While all compounds caused compensatory sleep responses, the magnitude of compensation observed for LSN2814617 was much smaller than would be predicted to result from the prolongation of wakefulness exhibited. Using simple response latencies to index performance, an mGlu5 PAM dramatically increased wakefulness and improved functional capacity of sleep-restricted animals, without eliciting a proportionate compensatory sleep response. This effect was qualitatively distinct from that of amphetamine, caffeine and modafinil. PMID:25902875

  20. Maximizing Sensitivity of the Psychomotor Vigilance Test (PVT) to Sleep Loss

    PubMed Central

    Basner, Mathias; Dinges, David F.

    2011-01-01

    Study Objectives: The psychomotor vigilance test (PVT) is among the most widely used measures of behavioral alertness, but there is large variation among published studies in PVT performance outcomes and test durations. To promote standardization of the PVT and increase its sensitivity and specificity to sleep loss, we determined PVT metrics and task durations that optimally discriminated sleep deprived subjects from alert subjects. Design: Repeated-measures experiments involving 10-min PVT assessments every 2 h across both acute total sleep deprivation (TSD) and 5 days of chronic partial sleep deprivation (PSD). Setting: Controlled laboratory environment. Participants: 74 healthy subjects (34 female), aged 22–45 years. Interventions: TSD experiment involving 33 h awake (N = 31 subjects) and a PSD experiment involving 5 nights of 4 h time in bed (N = 43 subjects). Measurements and Results: In a paired t-test paradigm and for both TSD and PSD, effect sizes of 10 different PVT performance outcomes were calculated. Effect sizes were high for both TSD (1.59–1.94) and PSD (0.88–1.21) for PVT metrics related to lapses and to measures of psychomotor speed, i.e., mean 1/RT (response time) and mean slowest 10% 1/RT. In contrast, PVT mean and median RT outcomes scored low to moderate effect sizes influenced by extreme values. Analyses facilitating only portions of the full 10-min PVT indicated that for some outcomes, high effect sizes could be achieved with PVT durations considerably shorter than 10 min, although metrics involving lapses seemed to profit from longer test durations in TSD. Conclusions: Due to their superior conceptual and statistical properties and high sensitivity to sleep deprivation, metrics involving response speed and lapses should be considered primary outcomes for the 10-min PVT. In contrast, PVT mean and median metrics, which are among the most widely used outcomes, should be avoided as primary measures of alertness. Our analyses also suggest

  1. Human disturbances, habitat characteristics and social environment generate sex-specific responses in vigilance of Mediterranean mouflon.

    PubMed

    Benoist, Stéphanie; Garel, Mathieu; Cugnasse, Jean-Marc; Blanchard, Pierrick

    2013-01-01

    In prey species, vigilance is an important part of the decision making process related to predation risk effects. Therefore, understanding the mechanisms shaping vigilance behavior provides relevant insights on factors influencing individual fitness. We investigated the role of extrinsic and intrinsic factors on vigilance behavior in Mediterranean mouflon (Ovis gmelini musimon×Ovis sp.) in a study site spatially and temporally contrasted in human pressures. Both sexes were less vigilant in the wildlife reserve compared to surrounding unprotected areas, except for males during the hunting period. During this period, males tended to be less strictly restricted to the reserve than females what might lead to a pervasive effect of hunting within the protected area, resulting in an increase in male vigilance. It might also be a rutting effect that did not occur in unprotected areas because males vigilance was already maximal in response to human disturbances. In both sexes, yearlings were less vigilant than adults, probably because they traded off vigilance for learning and energy acquisition and/or because they relied on adult experience present in the group. Similarly, non-reproductive females benefited of the vigilance effort provided by reproductive females when belonging to the same group. However, in the absence of reproductive females, non-reproductive females were as vigilant as reproductive females. Increasing group size was only found to reduce vigilance in females (up to 17.5%), not in males. We also showed sex-specific responses to habitat characteristics. Females increased their vigilance when habitat visibility decreased (up to 13.8%) whereas males increased their vigilance when feeding on low quality sites, i.e., when concomitant increase in chewing time can be devoted to vigilance with limited costs. Our global approach was able to disentangle the sex-specific sources of variation in mouflon vigilance and stressed the importance of reserves in managing

  2. Human Disturbances, Habitat Characteristics and Social Environment Generate Sex-Specific Responses in Vigilance of Mediterranean Mouflon

    PubMed Central

    Benoist, Stéphanie; Garel, Mathieu; Cugnasse, Jean-Marc; Blanchard, Pierrick

    2013-01-01

    In prey species, vigilance is an important part of the decision making process related to predation risk effects. Therefore, understanding the mechanisms shaping vigilance behavior provides relevant insights on factors influencing individual fitness. We investigated the role of extrinsic and intrinsic factors on vigilance behavior in Mediterranean mouflon (Ovis gmelini musimon×Ovis sp.) in a study site spatially and temporally contrasted in human pressures. Both sexes were less vigilant in the wildlife reserve compared to surrounding unprotected areas, except for males during the hunting period. During this period, males tended to be less strictly restricted to the reserve than females what might lead to a pervasive effect of hunting within the protected area, resulting in an increase in male vigilance. It might also be a rutting effect that did not occur in unprotected areas because males vigilance was already maximal in response to human disturbances. In both sexes, yearlings were less vigilant than adults, probably because they traded off vigilance for learning and energy acquisition and/or because they relied on adult experience present in the group. Similarly, non-reproductive females benefited of the vigilance effort provided by reproductive females when belonging to the same group. However, in the absence of reproductive females, non-reproductive females were as vigilant as reproductive females. Increasing group size was only found to reduce vigilance in females (up to 17.5%), not in males. We also showed sex-specific responses to habitat characteristics. Females increased their vigilance when habitat visibility decreased (up to 13.8%) whereas males increased their vigilance when feeding on low quality sites, i.e., when concomitant increase in chewing time can be devoted to vigilance with limited costs. Our global approach was able to disentangle the sex-specific sources of variation in mouflon vigilance and stressed the importance of reserves in managing

  3. Sturge-Weber syndrome: Continued vigilance is needed

    PubMed Central

    Hassan, Saeed; Babiker, Amir; Bashiri, Fahad A; Hassan, Hamdi H; Husseini, Maha El; Salih, Mustafa A

    2015-01-01

    Sturge-Weber syndrome (SWS) is a non-hereditary congenital disorder due to somatic mosaic mutations in the GNAQ gene. The classical presentation relates to the brain lesion (cerebral angiomatous lesion of leptomeninges, which is responsible for epileptic seizures, hemiparesis and mental retardation), skin lesion (unilateral facial nevus), ocular and oral involvement. We present a 12-year-old boy who was referred to the Division of Pediatric Neurology, King Saud University Medical City, Riyadh, Saudi Arabia with left-sided hemiparesis. Physical examination showed a port wine stain involving the right side of the face, extending to the upper thorax, and enlargement of both the right eye globe and cornea (megalocornea), indicating the presence of glaucoma. Following urgent referral to ophthalmology service, his eye condition improved dramatically post surgery. Neuroradiological investigations, including cranial computed tomography (CT) and magnetic resonance angiography (MRI) revealed the classical brain lesions of SWS, as well as right leptomeningeal choroidal angioma. Ten months later, he developed focal-onset seizures which responded to treatment. His cognition is normal with good school performance. Continued vigilance is needed to identify and manage the complications of SWS.

  4. Vigilant Eagle: ground-based countermeasure system against MANPADS

    NASA Astrophysics Data System (ADS)

    Vollin, Jeff

    2006-05-01

    Man-Portable Air Defense Systems, or MANPADS, have arisen as a major threat to commercial and military air traffic. While no MANPADS attacks have yet occurred within the United States, the risk posed by these weapons is undeniable. MANPADS were originally developed by the Soviet Union and the United States for tactical air defense, but since then these weapons have proliferated around the world. Two major approaches to countering these weapons have arisen: aircraft based and ground based. Aircraft-based systems typically use either flares or lasers to either confuse or blind the oncoming missile, thus driving it off target. These systems have been in use for many years on military aircraft and have been proven effective. However, when one considers the commercial air travel industry, the cost of providing a countermeasure system on every plane becomes prohibitive. A ground-based system by contrast protects every aircraft arriving or departing from an airport. By deploying a ground-based system at high-traffic and hub airports, a large percentage of the flying public can be protected affordably. Vigilant Eagle is such a ground based system which uses High Power Microwaves (HPM) to accomplish this mission.

  5. Heritability of anti-predatory traits: vigilance and locomotor performance in marmots.

    PubMed

    Blumstein, D T; Lea, A J; Olson, L E; Martin, J G A

    2010-05-01

    Animals must allocate some proportion of their time to detecting predators. In birds and mammals, such anti-predator vigilance has been well studied, and we know that it may be influenced by a variety of intrinsic and extrinsic factors. Despite hundreds of studies focusing on vigilance and suggestions that there are individual differences in vigilance, there have been no prior studies examining its heritability in the field. Here, we present one of the first reports of (additive) genetic variation in vigilance. Using a restricted maximum likelihood procedure, we found that, in yellow-bellied marmots (Marmota flaviventris), the heritability of locomotor ability (h(2)=0.21), and especially vigilance (h(2) = 0.08), is low. These modest heritability estimates suggest great environmental variation or a history of directional selection eliminating genetic variation in these traits. We also found a significant phenotypic (r(P) = -0.09 +/- 0.04, P = 0.024) and a substantial, but not significant, genetic correlation (r(A) = -0.57 +/- 0.28, P = 0.082) between the two traits (slower animals are less vigilant while foraging). We found no evidence of differential survival or longevity associated with particular phenotypes of either trait. The genetic correlation may persist because of environmental heterogeneity and genotype-by-environment interactions maintaining the correlation, or because there are two ways to solve the problem of foraging in exposed areas: be very vigilant and rely on early detection coupled with speed to escape, or reduce vigilance to minimize time spent in an exposed location. Both strategies seem to be equally successful, and this 'locomotor ability-wariness' syndrome may therefore allow slow animals to compensate behaviourally for their impaired locomotor ability. PMID:20298440

  6. Narrative vigilance: the analysis of stories in health care.

    PubMed

    Paley, John; Eva, Gail

    2005-04-01

    The idea of narrative has been widely discussed in the recent health care literature, including nursing, and has been portrayed as a resource for both clinical work and research studies. However, the use of the term 'narrative' is inconsistent, and various assumptions are made about the nature (and functions) of narrative: narrative as a naive account of events; narrative as the source of 'subjective truth'; narrative as intrinsically fictional; and narrative as a mode of explanation. All these assumptions have left their mark on the nursing literature, and all of them (in our view) are misconceived. Here, we argue that a failure to distinguish between 'narrative' and 'story' is partly responsible for these misconceptions, and we offer an analysis that shows why the distinction between them is essential. In doing so, we borrow the concept of 'narrativity' from literary criticism. Narrativity is something that a text has degrees of, and our proposal is that the elements of narrativity can be 'sorted' roughly into a continuum, at the 'high narrativity' end of which we find 'story'. On our account, 'story' is an interweaving of plot and character, whose organization is designed to elicit a certain emotional response from the reader, while 'narrative' refers to the sequence of events and the (claimed) causal connections between them. We suggest that it is important not to confuse the emotional persuasiveness of the 'story' with the objective accuracy of the 'narrative', and to this end we recommend what might be called 'narrative vigilance'. There is nothing intrinsically authentic, or sacrosanct, or emancipatory, or paradigmatic about narrative itself, even though the recent health care literature has had a marked tendency to romanticize it. PMID:15787904

  7. Adverse Effects of Daylight Saving Time on Adolescents' Sleep and Vigilance

    PubMed Central

    Medina, Diana; Ebben, Matthew; Milrad, Sara; Atkinson, Brianna; Krieger, Ana C.

    2015-01-01

    Study Objectives: Daylight saving time (DST) has been established with the intent to reduce energy expenditure, however unintentional effects on sleep and vigilance have not been consistently measured. The objective of this study was to test the hypothesis that DST adversely affects high school students' sleep and vigilance on the school days following its implementation. Methods: A natural experiment design was used to assess baseline and post-DST differences in objective and subjective measures of sleep and vigilance by actigraphy, sleep diary, sleepiness scale, and psychomotor vigilance testing (PVT). Students were tested during school days immediately preceding and following DST. Results: A total of 40 high school students were enrolled in this study; 35 completed the protocol. Sleep duration declined by an average of 32 minutes on the weeknights post-DST, reflecting a cumulative sleep loss of 2 h 42 min as compared to the baseline week (p = 0.001). This finding was confirmed by sleep diary analyses, reflecting an average sleep loss of 27 min/night (p = 0.004) post-DST. Vigilance significantly deteriorated, with a decline in PVT performance post-DST, resulting in longer reaction times (p < 0.001) and increased lapses (p < 0.001). Increased daytime sleepiness was also demonstrated (p < 0.001). Conclusions: The early March DST onset adversely affected sleep and vigilance in high school students resulting in increased daytime sleepiness. Larger scale evaluations of sleep impairments related to DST are needed to further quantify this problem in the population. If confirmed, measures to attenuate sleep loss post-DST should be implemented. Citation: Medina D, Ebben M, Milrad S, Atkinson B, Krieger AC. Adverse effects of daylight saving time on adolescents' sleep and vigilance. J Clin Sleep Med 2015;11(8):879–884. PMID:25979095

  8. Psychophysiological Control of Acognitive Task Using Adaptive Automation

    NASA Technical Reports Server (NTRS)

    Freeman, Frederick; Pope, Alan T. (Technical Monitor)

    2001-01-01

    The major focus of the present proposal was to examine psychophysiological variables related to hazardous states of awareness induced by monitoring automated systems. With the increased use of automation in today's work environment, people's roles in the work place are being redefined from that of active participant to one of passive monitor. Although the introduction of automated systems has a number of benefits, there are also a number of disadvantages regarding worker performance. Byrne and Parasuraman have argued for the use of psychophysiological measures in the development and the implementation of adaptive automation. While both performance based and model based adaptive automation have been studied, the use of psychophysiological measures, especially EEG, offers the advantage of real time evaluation of the state of the subject. The current study used the closed-loop system, developed at NASA-Langley Research Center, to control the state of awareness of subjects while they performed a cognitive vigilance task. Previous research in our laboratory, supported by NASA, has demonstrated that, in an adaptive automation, closed-loop environment, subjects perform a tracking task better under a negative than a positive, feedback condition. In addition, this condition produces less subjective workload and larger P300 event related potentials to auditory stimuli presented in a concurrent oddball task. We have also recently shown that the closed-loop system used to control the level of automation in a tracking task can also be used to control the event rate of stimuli in a vigilance monitoring task. By changing the event rate based on the subject's index of arousal, we have been able to produce improved monitoring, relative to various control groups. We have demonstrated in our initial closed-loop experiments with the the vigilance paradigm that using a negative feedback contingency (i.e. increasing event rates when the EEG index is low and decreasing event rates when

  9. Repression versus sensitization in response to media violence as predictors of cognitive avoidance and vigilance.

    PubMed

    Krahé, Barbara; Möller, Ingrid; Berger, Anja; Felber, Juliane

    2011-02-01

    Repression and sensitization as situational modes of coping with anxiety were examined as predictors of trait measures of cognitive avoidance and vigilance. In this study, 303 undergraduates saw a violent film clip to elicit anxiety. Increases in skin conductance level (SCL) and state anxiety (STA) from baseline were measured to identify repressors (high SCL, low STA) and contrast them with sensitizers (low SCL, high STA) and genuinely low anxious individuals (low SCL, low STA). State anger was also recorded. Trait measures of vigilance and cognitive avoidance were collected 2 weeks earlier. Significant SCL × STA interactions indicated that repressors scored higher on cognitive avoidance and lower on vigilance compared to sensitizers and low anxious participants. Repressors were less likely than sensitizers to report gaze avoidance during the clip. The anger by SCL interaction was nonsignificant, suggesting that repressors and sensitizers differ specifically in the processing of anxiety rather than negative affect in general. PMID:21223268

  10. Protection from ischemic heart injury by a vigilant heme oxygenase-1 plasmid system.

    PubMed

    Tang, Yao Liang; Tang, Yi; Zhang, Y Clare; Qian, Keping; Shen, Leping; Phillips, M Ian

    2004-04-01

    Although human heme oxygenase-1 (hHO-1) could provide a useful approach for cellular protection in the ischemic heart, constitutive overexpression of hHO-1 may lead to unwanted side effects. To avoid this, we designed a hypoxia-regulated hHO-1 gene therapy system that can be switched on and off. This vigilant plasmid system is composed of myosin light chain-2v promoter and a gene switch that is based on an oxygen-dependent degradation domain from the hypoxia inducible factor-1-alpha. The vector can sense ischemia and switch on the hHO-1 gene system, specifically in the heart. In an in vivo experiment, the vigilant hHO-1 plasmid or saline was injected intramyocardially into myocardial infarction mice or sham operation mice. After gene transfer, expression of hHO-1 was only detected in the ischemic heart treated with vigilant hHO-1 plasmids. Masson trichrome staining showed significantly fewer fibrotic areas in vigilant hHO-1 plasmids-treated mice compared with saline control (43.0%+/-4.8% versus 62.5%+/-3.3%, P<0.01). The reduction of interstitial fibrosis is accompanied by an increase in myocardial hHO-1 expression in peri-infarct border areas, concomitant with higher Bcl-2 levels and lower Bax, Bak, and caspase 3 levels in the ischemic myocardium compared with saline control. By use of a cardiac catheter, heart from vigilant hHO-1 plasmids-treated mice showed improved recovery of contractile and diastolic performance after myocardial infarction compared with saline control. This study documents the beneficial regulation and therapeutic potential of vigilant plasmid-mediated hHO-1 gene transfer. This novel gene transfer strategy can provide cardiac-specific protection from future repeated bouts of ischemic injury. PMID:14981066

  11. Task-Dependent Individual Differences in Prefrontal Connectivity

    PubMed Central

    Biswal, Bharat B.; Eldreth, Dana A.; Motes, Michael A.

    2010-01-01

    Recent advances in neuroimaging have permitted testing of hypotheses regarding the neural bases of individual differences, but this burgeoning literature has been characterized by inconsistent results. To test the hypothesis that differences in task demands could contribute to between-study variability in brain-behavior relationships, we had participants perform 2 tasks that varied in the extent of cognitive involvement. We examined connectivity between brain regions during a low-demand vigilance task and a higher-demand digit–symbol visual search task using Granger causality analysis (GCA). Our results showed 1) Significant differences in numbers of frontoparietal connections between low- and high-demand tasks 2) that GCA can detect activity changes that correspond with task-demand changes, and 3) faster participants showed more vigilance-related activity than slower participants, but less visual-search activity. These results suggest that relatively low-demand cognitive performance depends on spontaneous bidirectionally fluctuating network activity, whereas high-demand performance depends on a limited, unidirectional network. The nature of brain-behavior relationships may vary depending on the extent of cognitive demand. High-demand network activity may reflect the extent to which individuals require top-down executive guidance of behavior for successful task performance. Low-demand network activity may reflect task- and performance monitoring that minimizes executive requirements for guidance of behavior. PMID:20064942

  12. Human Activity Dampens the Benefits of Group Size on Vigilance in Khulan (Equus hemionus) in Western China.

    PubMed

    Wang, Mu-Yang; Ruckstuhl, Kathreen E; Xu, Wen-Xuan; Blank, David; Yang, Wei-Kang

    2016-01-01

    Animals receive anti-predator benefits from social behavior. As part of a group, individuals spend less time being vigilant, and vigilance decreases with increasing group size. This phenomenon, called "the many-eyes effect", together with the "encounter dilution effect", is considered among the most important factors determining individual vigilance behavior. However, in addition to group size, other social and environmental factors also influence the degree of vigilance, including disturbance from human activities. In our study, we examined vigilance behavior of Khulans (Equus hemionus) in the Xinjiang Province in western China to test whether and how human disturbance and group size affect vigilance. According to our results, Khulan showed a negative correlation between group size and the percentage time spent vigilant, although this negative correlation depended on the groups' disturbance level. Khulan in the more disturbed area had a dampened benefit from increases in group size, compared to those in the undisturbed core areas. Provision of continuous areas of high-quality habitat for Khulans will allow them to form larger undisturbed aggregations and to gain foraging benefits through reduced individual vigilance, as well as anti-predator benefits through increased probability of predator detection. PMID:26756993

  13. Human Activity Dampens the Benefits of Group Size on Vigilance in Khulan (Equus hemionus) in Western China

    PubMed Central

    Wang, Mu-Yang; Ruckstuhl, Kathreen E.; Xu, Wen-Xuan; Blank, David; Yang, Wei-Kang

    2016-01-01

    Animals receive anti-predator benefits from social behavior. As part of a group, individuals spend less time being vigilant, and vigilance decreases with increasing group size. This phenomenon, called “the many-eyes effect”, together with the “encounter dilution effect”, is considered among the most important factors determining individual vigilance behavior. However, in addition to group size, other social and environmental factors also influence the degree of vigilance, including disturbance from human activities. In our study, we examined vigilance behavior of Khulans (Equus hemionus) in the Xinjiang Province in western China to test whether and how human disturbance and group size affect vigilance. According to our results, Khulan showed a negative correlation between group size and the percentage time spent vigilant, although this negative correlation depended on the groups’ disturbance level. Khulan in the more disturbed area had a dampened benefit from increases in group size, compared to those in the undisturbed core areas. Provision of continuous areas of high-quality habitat for Khulans will allow them to form larger undisturbed aggregations and to gain foraging benefits through reduced individual vigilance, as well as anti-predator benefits through increased probability of predator detection. PMID:26756993

  14. 21 CFR 26.50 - Alert system and exchange of postmarket vigilance reports.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Alert system and exchange of postmarket vigilance reports. 26.50 Section 26.50 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL MUTUAL RECOGNITION OF PHARMACEUTICAL GOOD MANUFACTURING PRACTICE REPORTS, MEDICAL...

  15. 21 CFR 26.50 - Alert system and exchange of postmarket vigilance reports.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Alert system and exchange of postmarket vigilance reports. 26.50 Section 26.50 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL MUTUAL RECOGNITION OF PHARMACEUTICAL GOOD MANUFACTURING PRACTICE REPORTS, MEDICAL...

  16. 21 CFR 26.50 - Alert system and exchange of postmarket vigilance reports.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Alert system and exchange of postmarket vigilance reports. 26.50 Section 26.50 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL MUTUAL RECOGNITION OF PHARMACEUTICAL GOOD MANUFACTURING PRACTICE REPORTS, MEDICAL...

  17. Netizenship Politics: Youth, Anti-Americanism, and Rhetorical Agency in South Korea's 2002 Candlelight Vigils

    ERIC Educational Resources Information Center

    Kang, Jiyeon

    2009-01-01

    This study offers a rhetorical analysis of the 2002 South Korean Candlelight Vigils ["ch'otpul siwi"] with a focus on the role of the Internet in public opinion building, the rise in anti-American sentiment in South Korea, and rhetorical agency residing in the collective. In 2002, two South Korean schoolgirls walking along a rural road near Seoul…

  18. Two-Year-Olds Are Vigilant of Others' Non-Verbal Cues to Credibility

    ERIC Educational Resources Information Center

    Birch, Susan A. J.; Akmal, Nazanin; Frampton, Kristen L.

    2010-01-01

    Data from three experiments provide the first evidence that children, at least as young as age two, are vigilant of others' non-verbal cues to credibility, and flexibly use these cues to facilitate learning. Experiment 1 revealed that 2- and 3-year-olds prefer to learn about objects from someone who appears, through non-verbal cues, to be…

  19. What can the drivers' own description from combined sources provide in an analysis of driver distraction and low vigilance in accident situations?

    PubMed

    Tivesten, Emma; Wiberg, Henrik

    2013-03-01

    Accident data play an important role in vehicle safety development. Accident data sources are generally limited in terms of how much information is provided on driver states and behaviour prior to an accident. However, the precise limitations vary between databases, due to differences in analysis focus and data collection procedures between organisations. If information about a specific accident can be retrieved from more than one data source it should be possible to combine the available information sets to facilitate data from one source to compensate for limitations in the other(s). To investigate the viability of such compensation, this study identified a set of accidents recorded in two different data sources. The first data source investigated was an accident mail survey and the second data source insurance claims documents consisting predominantly of insurance claims completed by the involved road users. An analysis of survey variables was compared to a case analysis including word data derived from the same survey and filed insurance claims documents. For each accident, the added value of having access to more than one source of information was assessed. To limit the scope of this study, three particular topics were investigated: available information on low vigilance (e.g., being drowsy, ill); secondary task distraction (e.g., talking with passengers, mobile phone use); and distraction related to the driving task (e.g., looking for approaching vehicles). Results suggest that for low vigilance and secondary task distraction, a combination of the mail survey and insurance claims documents provide more reliable and detailed pre-crash information than survey variables alone. However, driving related distraction appears to be more difficult to capture. In order to gain a better understanding of the above issues and how frequently they occur in accidents, the data sources and analysis methods suggested here may be combined with other investigation methods such

  20. Prediction of Vigilant Attention and Cognitive Performance Using Self-Reported Alertness, Circadian Phase, Hours since Awakening, and Accumulated Sleep Loss

    PubMed Central

    Bermudez, Eduardo B.; Klerman, Elizabeth B.; Czeisler, Charles A.; Cohen, Daniel A.; Wyatt, James K.; Phillips, Andrew J. K.

    2016-01-01

    Sleep restriction causes impaired cognitive performance that can result in adverse consequences in many occupational settings. Individuals may rely on self-perceived alertness to decide if they are able to adequately perform a task. It is therefore important to determine the relationship between an individual’s self-assessed alertness and their objective performance, and how this relationship depends on circadian phase, hours since awakening, and cumulative lost hours of sleep. Healthy young adults (aged 18–34) completed an inpatient schedule that included forced desynchrony of sleep/wake and circadian rhythms with twelve 42.85-hour “days” and either a 1:2 (n = 8) or 1:3.3 (n = 9) ratio of sleep-opportunity:enforced-wakefulness. We investigated whether subjective alertness (visual analog scale), circadian phase (melatonin), hours since awakening, and cumulative sleep loss could predict objective performance on the Psychomotor Vigilance Task (PVT), an Addition/Calculation Test (ADD) and the Digit Symbol Substitution Test (DSST). Mathematical models that allowed nonlinear interactions between explanatory variables were evaluated using the Akaike Information Criterion (AIC). Subjective alertness was the single best predictor of PVT, ADD, and DSST performance. Subjective alertness alone, however, was not an accurate predictor of PVT performance. The best AIC scores for PVT and DSST were achieved when all explanatory variables were included in the model. The best AIC score for ADD was achieved with circadian phase and subjective alertness variables. We conclude that subjective alertness alone is a weak predictor of objective vigilant or cognitive performance. Predictions can, however, be improved by knowing an individual’s circadian phase, current wake duration, and cumulative sleep loss. PMID:27019198

  1. Prediction of Vigilant Attention and Cognitive Performance Using Self-Reported Alertness, Circadian Phase, Hours since Awakening, and Accumulated Sleep Loss.

    PubMed

    Bermudez, Eduardo B; Klerman, Elizabeth B; Czeisler, Charles A; Cohen, Daniel A; Wyatt, James K; Phillips, Andrew J K

    2016-01-01

    Sleep restriction causes impaired cognitive performance that can result in adverse consequences in many occupational settings. Individuals may rely on self-perceived alertness to decide if they are able to adequately perform a task. It is therefore important to determine the relationship between an individual's self-assessed alertness and their objective performance, and how this relationship depends on circadian phase, hours since awakening, and cumulative lost hours of sleep. Healthy young adults (aged 18-34) completed an inpatient schedule that included forced desynchrony of sleep/wake and circadian rhythms with twelve 42.85-hour "days" and either a 1:2 (n = 8) or 1:3.3 (n = 9) ratio of sleep-opportunity:enforced-wakefulness. We investigated whether subjective alertness (visual analog scale), circadian phase (melatonin), hours since awakening, and cumulative sleep loss could predict objective performance on the Psychomotor Vigilance Task (PVT), an Addition/Calculation Test (ADD) and the Digit Symbol Substitution Test (DSST). Mathematical models that allowed nonlinear interactions between explanatory variables were evaluated using the Akaike Information Criterion (AIC). Subjective alertness was the single best predictor of PVT, ADD, and DSST performance. Subjective alertness alone, however, was not an accurate predictor of PVT performance. The best AIC scores for PVT and DSST were achieved when all explanatory variables were included in the model. The best AIC score for ADD was achieved with circadian phase and subjective alertness variables. We conclude that subjective alertness alone is a weak predictor of objective vigilant or cognitive performance. Predictions can, however, be improved by knowing an individual's circadian phase, current wake duration, and cumulative sleep loss. PMID:27019198

  2. Changes in functional connectivity dynamics associated with vigilance network in taxi drivers.

    PubMed

    Shen, Hui; Li, Zhenfeng; Qin, Jian; Liu, Qiang; Wang, Lubin; Zeng, Ling-Li; Li, Hong; Hu, Dewen

    2016-01-01

    An increasing number of neuroimaging studies have suggested that the fluctuations of low-frequency resting-state functional connectivity (FC) are not noise but are instead linked to the shift between distinct cognitive states. However, there is very limited knowledge about whether and how the fluctuations of FC at rest are influenced by long-term training and experience. Here, we investigated how the dynamics of resting-state FC are linked to driving behavior by comparing 20 licensed taxi drivers with 20 healthy non-drivers using a sliding window approach. We found that the driving experience could be effectively decoded with 90% (p<0.001) accuracy by the amplitude of low-frequency fluctuations in some specific connections, based on a multivariate pattern analysis technique. Interestingly, the majority of these connections fell within a set of distributed regions named "the vigilance network". Moreover, the decreased amplitude of the FC fluctuations within the vigilance network in the drivers was negatively correlated with the number of years that they had driven a taxi. Furthermore, temporally quasi-stable functional connectivity segmentation revealed significant differences between the drivers and non-drivers in the dwell time of specific vigilance-related transient brain states, although the brain's repertoire of functional states was preserved. Overall, these results suggested a significant link between the changes in the time-dependent aspects of resting-state FC within the vigilance network and long-term driving experiences. The results not only improve our understanding of how the brain supports driving behavior but also shed new light on the relationship between the dynamics of functional brain networks and individual behaviors. PMID:26363345

  3. The Moral, Epistemic, and Mindreading Components of Children's Vigilance towards Deception

    ERIC Educational Resources Information Center

    Mascaro, Olivier; Sperber, Dan

    2009-01-01

    Vigilance towards deception is investigated in 3- to-5-year-old children: (i) In Study 1, children as young as 3 years of age prefer the testimony of a benevolent rather than of a malevolent communicator. (ii) In Study 2, only at the age of four do children show understanding of the falsity of a lie uttered by a communicator described as a liar.…

  4. [Interest of a collaboration between the vigilances' coordination and care-related risks management committees in a health care center].

    PubMed

    Lassale, B; Ragni, J; Besse-Moreau, M

    2013-05-01

    Health care vigilance committees appeared with time in France. Some vigilance entities are present at a regional level, but all are found at the National Drugs and Health Care Products Safety Agency. Along with health care centers' certification, vigilance committees' coordination has evolved: whereas its presence was optional in the first version of certification, it has now imposed itself within health care centers with the more recent versions of certification, detailing the actions it must undertake. In parallel, a lot of attention is put on health care-related risk management with a health care center. Vigilances' coordination can thus take advantage of this in sharing an incident declaration system common with that of health care-related risks management. This collaboration will enable the generation of a priori risks' maps, help analyze adverse events and use the notion of criticality within a global safe care policy in each health care facility. PMID:23587622

  5. How Preferences For Eager Versus Vigilant Judgment Strategies Affect Self-Serving Conclusions

    PubMed Central

    Molden, Daniel C.; Higgins, E. Tory

    2008-01-01

    People are often motivated to reach self-serving conclusions during judgment. This article examines how such self-serving judgment outcomes are influenced by preferences for different judgment strategies. Two studies tested how preferences for eager (promotion-oriented) versus vigilant (prevention-oriented) judgment strategies affected self-serving explanations for success or failure. Regardless of their performance, those preferring vigilant strategies selectively endorsed a few explanations above others, whereas those preferring eager strategies more evenly endorsed multiple explanations. Furthermore, although the explanations selected by those preferring vigilant strategies were indeed self-serving (emphasizing personal responsibility for success and external circumstances for failure), the more balanced endorsement of multiple explanations by those preferring eager strategies was associated with attenuated self-serving tendencies. Finally, those preferring eager strategies were also less self-serving in their generalization from explanations of current performance to predictions of future performance. The larger implications of these findings for the role of strategic preferences in judgment are discussed. PMID:19727421

  6. Group Dynamics in Top Management Teams: Groupthink, Vigilance, and Alternative Models of Organizational Failure and Success.

    PubMed

    Peterson; Owens; Tetlock; Fan; Martorana

    1998-02-01

    This study explored the heuristic value of Janis' (1982) groupthink and vigilant decision making models as explanations of failure and success in top management team decision making using the Organizational Group Dynamics Q-sort (GDQ). Top management teams of seven Fortune 500 companies were examined at two historical junctures-one when the team was successful (defined as satisfying strategic constituencies) and one when the team was unsuccessful. Results strongly supported the notion that a group' decision making process is systematically related to the outcomes experienced by the team. Ideal-type Q-sorts organized around Janis' analysis of groupthink and vigilance were substantially correlated with Q-sorts of failing and successful groups, respectively. The fit was, however, far from perfect. Ideal-type Q-sorts derived from other frameworks correlated better with the failure-success classification than did the Janis-derived ideal types. Successful groups showed some indicators of groupthink (e.g., risk-taking, cohesion, and strong, opinionated leaders), whereas unsuccessful groups showed signs of vigilance (e.g., internal debate to the point of factionalism). The results illustrate the usefulness of the GDQ for developing and empirically testing theory in organizational behavior from historical cases. Copyright 1998 Academic Press. PMID:9705805

  7. Dolphins Can Maintain Vigilant Behavior through Echolocation for 15 Days without Interruption or Cognitive Impairment

    PubMed Central

    Branstetter, Brian K.; Finneran, James J.; Fletcher, Elizabeth A.; Weisman, Brian C.; Ridgway, Sam H.

    2012-01-01

    In dolphins, natural selection has developed unihemispheric sleep where alternating hemispheres of their brain stay awake. This allows dolphins to maintain consciousness in response to respiratory demands of the ocean. Unihemispheric sleep may also allow dolphins to maintain vigilant states over long periods of time. Because of the relatively poor visibility in the ocean, dolphins use echolocation to interrogate their environment. During echolocation, dolphin produce clicks and listen to returning echoes to determine the location and identity of objects. The extent to which individual dolphins are able to maintain continuous vigilance through this active sense is unknown. Here we show that dolphins may continuously echolocate and accurately report the presence of targets for at least 15 days without interruption. During a total of three sessions, each lasting five days, two dolphins maintained echolocation behaviors while successfully detecting and reporting targets. Overall performance was between 75 to 86% correct for one dolphin and 97 to 99% correct for a second dolphin. Both animals demonstrated diel patterns in echolocation behavior. A 15-day testing session with one dolphin resulted in near perfect performance with no significant decrement over time. Our results demonstrate that dolphins can continuously monitor their environment and maintain long-term vigilant behavior through echolocation. PMID:23082170

  8. Dolphins can maintain vigilant behavior through echolocation for 15 days without interruption or cognitive impairment.

    PubMed

    Branstetter, Brian K; Finneran, James J; Fletcher, Elizabeth A; Weisman, Brian C; Ridgway, Sam H

    2012-01-01

    In dolphins, natural selection has developed unihemispheric sleep where alternating hemispheres of their brain stay awake. This allows dolphins to maintain consciousness in response to respiratory demands of the ocean. Unihemispheric sleep may also allow dolphins to maintain vigilant states over long periods of time. Because of the relatively poor visibility in the ocean, dolphins use echolocation to interrogate their environment. During echolocation, dolphin produce clicks and listen to returning echoes to determine the location and identity of objects. The extent to which individual dolphins are able to maintain continuous vigilance through this active sense is unknown. Here we show that dolphins may continuously echolocate and accurately report the presence of targets for at least 15 days without interruption. During a total of three sessions, each lasting five days, two dolphins maintained echolocation behaviors while successfully detecting and reporting targets. Overall performance was between 75 to 86% correct for one dolphin and 97 to 99% correct for a second dolphin. Both animals demonstrated diel patterns in echolocation behavior. A 15-day testing session with one dolphin resulted in near perfect performance with no significant decrement over time. Our results demonstrate that dolphins can continuously monitor their environment and maintain long-term vigilant behavior through echolocation. PMID:23082170

  9. Early experience affects the strength of vigilance for threat in rhesus monkey infants

    PubMed Central

    Mandalaywala, Tara M.; Parker, Karen J.; Maestripieri, Dario

    2014-01-01

    Both human and nonhuman primates exhibit a cognitive bias to social threat, but little is known about how this bias develops. We investigated the development of threat bias in free-ranging infant rhesus macaques (Macaca mulatta) at 3 (N = 45) and 9 (N = 46) months of age. Three-month-old infant monkeys did not display bias, but 9-month-olds exhibited increased maintenance of attention to threatening social stimuli (vigilance for threat). To examine whether the social environment affected vigilance for threat, behavioral data on maternal rank and protectiveness were collected across the first 12 weeks of life for infants tested at 9 months. Nine-month-old infants of high-ranking mothers and more protective mothers displayed greater vigilance for threat than infants of lower-ranking and less protective mothers. These results demonstrate that infant social cognition is malleable and shaped by mothers both directly (protectiveness) and indirectly (rank), as maternal characteristics affect infants’ social experiences. PMID:25125426

  10. Coordinated vigilance provides evidence for direct reciprocity in coral reef fishes

    PubMed Central

    Brandl, Simon J.; Bellwood, David R.

    2015-01-01

    Reciprocity is frequently assumed to require complex cognitive abilities. Therefore, it has been argued that reciprocity may be restricted to animals that can meet these demands. Here, we provide evidence for the potential presence of direct reciprocity in teleost fishes. We demonstrate that in pairs of coral reef rabbitfishes (f. Siganidae), one fish frequently assumes an upright vigilance position in the water column, while the partner forages in small crevices in the reef substratum. Both behaviours are strongly coordinated and partners regularly alternate their positions, resulting in a balanced distribution of foraging activity. Compared to solitary individuals, fishes in pairs exhibit longer vigilance bouts, suggesting that the help provided to the partner is costly. In turn, fishes in pairs take more consecutive bites and penetrate deeper into crevices than solitary individuals, suggesting that the safety provided by a vigilant partner may outweigh initial costs by increasing foraging efficiency. Thus, the described system appears to meet all of the requirements for direct reciprocity. We argue that the nature of rabbitfish pairs provides favourable conditions for the establishment of direct reciprocity, as continuous interaction with the same partner, simultaneous needs, interdependence, and communication relax the cognitive demands of reciprocal cooperation. PMID:26403250

  11. Antipredator vigilance of juvenile and adult thirteen-lined ground squirrels and the role of nutritional need.

    PubMed

    Arenz; Leger

    2000-03-01

    Juvenile thirteen-lined ground squirrels, Spermophilus tridecemlineatus, are less vigilant (i.e. they spend less time visually scanning the environment) than adults. To determine whether nutritional need was a potential cause of this difference, we supplemented two groups of free-ranging juveniles during the predispersal stage, while juveniles were still near and around the natal burrows. The high-energy food group (HEF: 11 squirrels) received peanut butter and oats while the low-energy food group (LEF: seven squirrels) received lettuce. Adults (14 squirrels) were also supplemented, but due to their greater home range sizes, it was not feasible to classify them as either HEF or LEF. To evaluate the effect of supplementation on antipredator vigilance, the behavioural act of visually scanning for predators, we videotaped individuals while they were foraging above ground during 5-min observation periods. Each squirrel was observed and weighed during three time periods over 23 days. From the videotape, we extracted measures of time spent vigilant, locomoting and foraging. All three categories of squirrels gained mass over the study period, but the HEF juveniles rapidly exceeded that of the LEF juveniles. Early in the study, LEF and HEF juveniles did not significantly differ in either body mass or time budgets, and, initially, both juvenile groups were similar to adults in the amount of time devoted to vigilance. Later in the study, the behaviour of HEF juveniles closely resembled that of adults (increased time devoted to vigilance and decreased time devoted to foraging), while LEF juveniles decreased vigilance and increased their foraging time. This study indicates that for thirteen-lined ground squirrels the lower vigilance of juveniles is due, at least in part, to the greater nutritional needs of young animals with consequent increases in foraging, which is largely incompatible with vigilance. Copyright 2000 The Association for the Study of Animal Behaviour. PMID

  12. Vigilance and Activity Time-Budget Adjustments of Wintering Hooded Cranes, Grus monacha, in Human-Dominated Foraging Habitats

    PubMed Central

    Li, Chunlin; Zhou, Lizhi; Xu, Li; Zhao, Niannian; Beauchamp, Guy

    2015-01-01

    Due to loss and degradation of natural wetlands, waterbirds increasingly rely on surrounding human-dominated habitats to obtain food. Quantifying vigilance patterns, investigating the trade-off among various activities, and examining the underlying mechanisms will help us understand how waterbirds adapt to human-caused disturbances. During two successive winters (November-February of 2012–13 and 2013–14), we studied the hooded crane, Grus monacha, in the Shengjin Lake National Nature Reserve (NNR), China, to investigate how the species responds to human disturbances through vigilance and activity time-budget adjustments. Our results showed striking differences in the behavior of the cranes when foraging in the highly disturbed rice paddy fields found in the buffer zone compared with the degraded natural wetlands in the core area of the NNR. Time spent vigilant decreased with flock size and cranes spent more time vigilant in the human-dominated buffer zone. In the rice paddy fields, the birds were more vigilant but also fed more at the expense of locomotion and maintenance activities. Adult cranes spent more time vigilant and foraged less than juveniles. We recommend habitat recovery in natural wetlands and community co-management in the surrounding human-dominated landscape for conservation of the hooded crane and, generally, for the vast numbers of migratory waterbirds wintering in the middle and lower reaches of the Yangtze River floodplain. PMID:25768111

  13. Vigilance and activity time-budget adjustments of wintering hooded cranes, Grus monacha, in human-dominated foraging habitats.

    PubMed

    Li, Chunlin; Zhou, Lizhi; Xu, Li; Zhao, Niannian; Beauchamp, Guy

    2015-01-01

    Due to loss and degradation of natural wetlands, waterbirds increasingly rely on surrounding human-dominated habitats to obtain food. Quantifying vigilance patterns, investigating the trade-off among various activities, and examining the underlying mechanisms will help us understand how waterbirds adapt to human-caused disturbances. During two successive winters (November-February of 2012-13 and 2013-14), we studied the hooded crane, Grus monacha, in the Shengjin Lake National Nature Reserve (NNR), China, to investigate how the species responds to human disturbances through vigilance and activity time-budget adjustments. Our results showed striking differences in the behavior of the cranes when foraging in the highly disturbed rice paddy fields found in the buffer zone compared with the degraded natural wetlands in the core area of the NNR. Time spent vigilant decreased with flock size and cranes spent more time vigilant in the human-dominated buffer zone. In the rice paddy fields, the birds were more vigilant but also fed more at the expense of locomotion and maintenance activities. Adult cranes spent more time vigilant and foraged less than juveniles. We recommend habitat recovery in natural wetlands and community co-management in the surrounding human-dominated landscape for conservation of the hooded crane and, generally, for the vast numbers of migratory waterbirds wintering in the middle and lower reaches of the Yangtze River floodplain. PMID:25768111

  14. No Effects of Acute Exposure to Wi-Fi Electromagnetic Fields on Spontaneous EEG Activity and Psychomotor Vigilance in Healthy Human Volunteers.

    PubMed

    Zentai, Norbert; Csathó, Árpád; Trunk, Attila; Fiocchi, Serena; Parazzini, Marta; Ravazzani, Paolo; Thuróczy, György; Hernádi, István

    2015-12-01

    Mobile equipment use of wireless fidelity (Wi-Fi) signal modulation has increased exponentially in the past few decades. However, there is inconclusive scientific evidence concerning the potential risks associated with the energy deposition in the brain from Wi-Fi and whether Wi-Fi electromagnetism interacts with cognitive function. In this study we investigated possible neurocognitive effects caused by Wi-Fi exposure. First, we constructed a Wi-Fi exposure system from commercial parts. Dosimetry was first assessed by free space radiofrequency field measurements. The experimental exposure system was then modeled based on real geometry and physical characteristics. Specific absorption rate (SAR) calculations were performed using a whole-body, realistic human voxel model with values corresponding to conventional everyday Wi-Fi exposure (peak SAR10g level was 99.22 mW/kg with 1 W output power and 100% duty cycle). Then, in two provocation experiments involving healthy human volunteers we tested for two hypotheses: 1. Whether a 60 min long 2.4 GHz Wi-Fi exposure affects the spectral power of spontaneous awake electroencephalographic (sEEG) activity (N = 25); and 2. Whether similar Wi-Fi exposure modulates the sustained attention measured by reaction time in a computerized psychomotor vigilance test (PVT) (N = 19). EEG data were recorded at midline electrode sites while volunteers watched a silent documentary. In the PVT task, button press reaction time was recorded. No measurable effects of acute Wi-Fi exposure were found on spectral power of sEEG or reaction time in the psychomotor vigilance test. These results indicate that a single, 60 min Wi-Fi exposure does not alter human oscillatory brain function or objective measures of sustained attention. PMID:26600173

  15. The interplay between aerobic metabolism and antipredator performance: vigilance is related to recovery rate after exercise

    PubMed Central

    Killen, Shaun S.; Reid, Donald; Marras, Stefano; Domenici, Paolo

    2015-01-01

    When attacked by a predator, fish respond with a sudden fast-start motion away from the threat. Although this anaerobically-powered swimming necessitates a recovery phase which is fueled aerobically, little is known about links between escape performance and aerobic traits such as aerobic scope (AS) or recovery time after exhaustive exercise. Slower recovery ability or a reduced AS could make some individuals less likely to engage in a fast-start response or display reduced performance. Conversely, increased vigilance in some individuals could permit faster responses to an attack but also increase energy demand and prolong recovery after anaerobic exercise. We examined how AS and the ability to recover from anaerobic exercise relates to differences in fast-start escape performance in juvenile golden gray mullet at different acclimation temperatures. Individuals were acclimated to either 18, 22, or 26°C, then measured for standard and maximal metabolic rates and AS using intermittent flow respirometry. Anaerobic capacity and the time taken to recover after exercise were also assessed. Each fish was also filmed during a simulated attack to determine response latency, maximum speed and acceleration, and turning rate displayed during the escape response. Across temperatures, individuals with shorter response latencies during a simulated attack are those with the longest recovery time after exhaustive anaerobic exercise. Because a short response latency implies high preparedness to escape, these results highlight the trade-off between the increased vigilance and metabolic demand, which leads to longer recovery times in fast reactors. These results improve our understanding of the intrinsic physiological traits that generate inter-individual variability in escape ability, and emphasize that a full appreciation of trade-offs associated with predator avoidance and energy balance must include energetic costs associated with vigilance and recovery from anaerobic exercise

  16. Age differences in arousal and vigilance in California ground squirrels (Spermophilus beecheyi).

    PubMed

    Hanson, M T; Coss, R G

    2001-11-01

    Newly emerged pup, juvenile, and adult California ground squirrels (Spermophilus beecheyi douglasii) were videorecorded at a seminatural field site in northern California. Video data revealed age differences in the budgeting of ground squirrel behavior, habitat use, and physiological arousal as indicated by morphometric analyses of tail piloerection. Adults and juveniles devoted their time to foraging in the open at feeding stations while displaying low to moderate levels of arousal, respectively. Pups remained vigilant on the fringe of covered habitats while displaying comparatively higher levels of arousal. Higher pup arousal may facilitate memory formation during early stages of development. PMID:11745313

  17. Time-on-task decrements in "steer clear" performance of patients with sleep apnea and narcolepsy

    NASA Technical Reports Server (NTRS)

    Findley, L. J.; Suratt, P. M.; Dinges, D. F.

    1999-01-01

    Loss of attention with time-on-task reflects the increasing instability of the waking state during performance in experimentally induced sleepiness. To determine whether patients with disorders of excessive sleepiness also displayed time-on-task decrements indicative of wake state instability, visual sustained attention performance on "Steer Clear," a computerized simple RT driving simulation task, was compared among 31 patients with untreated sleep apnea, 16 patients with narcolepsy, and 14 healthy control subjects. Vigilance decrement functions were generated by analyzing the number of collisions in each of six four-minute periods of Steer Clear task performance in a mixed-model analysis of variance and linear regression equations. As expected, patients had more Steer Clear collisions than control subjects (p=0.006). However, the inter-subject variability in errors among the narcoleptic patients was four-fold that of the apnea patients, and 100-fold that of the controls volunteers; the variance in errors among untreated apnea patients was 27-times that of controls. The results of transformed collision data revealed main effects for group (p=0.006), time-on-task (p=0.001), and a significant interaction (p=0.022). Control subjects showed no clear evidence of increasing collision errors with time-on-task (adjusted R2=0.22), while apnea patients showed a trend toward vigilance decrement (adjusted R2=0.42, p=0.097), and narcolepsy patients evidenced a robust linear vigilance decrement (adjusted R2=0.87, p=0.004). The association of disorders of excessive somnolence with escalating time-on-task decrements makes it imperative that when assessment of neurobehavioral performance is conducted in patients, it involves task durations and analyses that will evaluate the underlying vulnerability of potentially sleepy patients to decrements over time in tasks that require sustained attention and timely responses, both of which are key components in safe driving performance.

  18. OpenVigil FDA – Inspection of U.S. American Adverse Drug Events Pharmacovigilance Data and Novel Clinical Applications

    PubMed Central

    Böhm, Ruwen; von Hehn, Leocadie; Herdegen, Thomas; Klein, Hans-Joachim; Bruhn, Oliver; Petri, Holger; Höcker, Jan

    2016-01-01

    Pharmacovigilance contributes to health care. However, direct access to the underlying data for academic institutions and individual physicians or pharmacists is intricate, and easily employable analysis modes for everyday clinical situations are missing. This underlines the need for a tool to bring pharmacovigilance to the clinics. To address these issues, we have developed OpenVigil FDA, a novel web-based pharmacovigilance analysis tool which uses the openFDA online interface of the Food and Drug Administration (FDA) to access U.S. American and international pharmacovigilance data from the Adverse Event Reporting System (AERS). OpenVigil FDA provides disproportionality analyses to (i) identify the drug most likely evoking a new adverse event, (ii) compare two drugs concerning their safety profile, (iii) check arbitrary combinations of two drugs for unknown drug-drug interactions and (iv) enhance the relevance of results by identifying confounding factors and eliminating them using background correction. We present examples for these applications and discuss the promises and limits of pharmacovigilance, openFDA and OpenVigil FDA. OpenVigil FDA is the first public available tool to apply pharmacovigilance findings directly to real-life clinical problems. OpenVigil FDA does not require special licenses or statistical programs. PMID:27326858

  19. OpenVigil FDA - Inspection of U.S. American Adverse Drug Events Pharmacovigilance Data and Novel Clinical Applications.

    PubMed

    Böhm, Ruwen; von Hehn, Leocadie; Herdegen, Thomas; Klein, Hans-Joachim; Bruhn, Oliver; Petri, Holger; Höcker, Jan

    2016-01-01

    Pharmacovigilance contributes to health care. However, direct access to the underlying data for academic institutions and individual physicians or pharmacists is intricate, and easily employable analysis modes for everyday clinical situations are missing. This underlines the need for a tool to bring pharmacovigilance to the clinics. To address these issues, we have developed OpenVigil FDA, a novel web-based pharmacovigilance analysis tool which uses the openFDA online interface of the Food and Drug Administration (FDA) to access U.S. American and international pharmacovigilance data from the Adverse Event Reporting System (AERS). OpenVigil FDA provides disproportionality analyses to (i) identify the drug most likely evoking a new adverse event, (ii) compare two drugs concerning their safety profile, (iii) check arbitrary combinations of two drugs for unknown drug-drug interactions and (iv) enhance the relevance of results by identifying confounding factors and eliminating them using background correction. We present examples for these applications and discuss the promises and limits of pharmacovigilance, openFDA and OpenVigil FDA. OpenVigil FDA is the first public available tool to apply pharmacovigilance findings directly to real-life clinical problems. OpenVigil FDA does not require special licenses or statistical programs. PMID:27326858

  20. High-peak-power microwave pulses at 2. 37 GHz: No effects on vigilance performance in monkeys. Interim report, February 1988-February 1989

    SciTech Connect

    D'Andrea, J.A.; Knepton, J.; Cobb, B.L.; Klauenberg, B.J.; Merritt, J.H.

    1989-11-02

    The current safety standards for occupational exposure radio frequency and microwave exposure do not limit the peak power of microwave pulses. To evaluate whether short-duration (93 ns) high-peak-power microwave pulses can alter behavioral performance, four rhesus monkeys were exposed to peak powers of 7.02-11.30 kW/cm2 while they performed a vigilance task. The behavior consisted of two components: responding on a variable interval schedule on one lever and to reaction time on a second lever. Correct responding on each lever was signaled by auditory stimuli. Trained monkeys performed the task during exposure to 2.37-GHz microwave pulses delivered concurrently with the auditory signals. The estimated peak whole-body specific absorption rate (SAR) for each pulse was between 582.7 and 937.9 kW/kg (54-87 mJ/kg per pulse). Compared to sham irradiation, significant changes in behavioral performance were not observed.

  1. Better, Stronger, Faster Self-Serving Judgment, Affect Regulation, and the Optimal Vigilance Hypothesis

    PubMed Central

    Roese, Neal J.; Olson, James M.

    2008-01-01

    Self-serving judgments, in which the self is viewed more favorably than other people, are ubiquitous. Their dynamic variation within individuals may be explained in terms of the regulation of affect. Self-serving judgments produce positive emotions, and threat increases self-serving judgments (a compensatory pattern that restores affect to a set point or baseline). Perceived mutability is a key moderator of these judgments; low mutability (i.e., the circumstance is closed to modification) triggers a cognitive response aimed at affect regulation, whereas high mutability (i.e., the circumstance is open to further modification) activates direct behavioral remediation. Threats often require immediate response, whereas positive events do not. Because of this brief temporal window, an active mechanism is needed to restore negative (but not positive) affective shifts back to a set point. Without this active reset, an earlier threat would make the individual less vigilant toward a new threat. Thus, when people are sad, they aim to return their mood to baseline, often via self-serving judgments. We argue that asymmetric homeostasis enables optimal vigilance, which establishes a coherent theoretical account of the role of self-serving judgments in affect regulation. PMID:18552989

  2. Constant vigilance: mothers' work parenting young children with type 1 diabetes.

    PubMed

    Sullivan-Bolyai, S; Deatrick, J; Gruppuso, P; Tamborlane, W; Grey, M

    2003-02-01

    Little is known about the experiences of mothers raising young children with type 1 diabetes. The purpose of this study was to describe the day-to-day experiences of mothers (N = 28) raising young children under 4 years of age with type 1 diabetes. Descriptive, naturalistic inquiry principles were used to interview subjects, as well as to manage and analyze the data. The mothers reported using the management behavior of constant vigilance. Their concerns about hypoglycemia and providing competent care reflected the interplay between their fears and profound sense of responsibility for managing the disease. Mothers reported having to learn the management behaviors and to occasionally adjust the day-to-day management when either severe hypoglycemia or developmental milestones occurred. Although mothers initially had feelings of incompetence with the care they provided, with time, they became very skilled. There were also reports of limited access to babysitting, child care, or respite services. The intensity of their constant vigilance associated with their concerns, responsibility, and lack of supports resulted in some mothers having physical and/or emotional problems. The findings of the study highlight the importance of identifying family and/or community resources that may provide mothers with support that could reduce some of the tremendous stress and burden of responsibility experienced after diagnosis of diabetes. PMID:12610784

  3. Neurofeedback in ADHD and insomnia: vigilance stabilization through sleep spindles and circadian networks.

    PubMed

    Arns, Martijn; Kenemans, J Leon

    2014-07-01

    In this review article an overview of the history and current status of neurofeedback for the treatment of ADHD and insomnia is provided. Recent insights suggest a central role of circadian phase delay, resulting in sleep onset insomnia (SOI) in a sub-group of ADHD patients. Chronobiological treatments, such as melatonin and early morning bright light, affect the suprachiasmatic nucleus. This nucleus has been shown to project to the noradrenergic locus coeruleus (LC) thereby explaining the vigilance stabilizing effects of such treatments in ADHD. It is hypothesized that both Sensori-Motor Rhythm (SMR) and Slow-Cortical Potential (SCP) neurofeedback impact on the sleep spindle circuitry resulting in increased sleep spindle density, normalization of SOI and thereby affect the noradrenergic LC, resulting in vigilance stabilization. After SOI is normalized, improvements on ADHD symptoms will occur with a delayed onset of effect. Therefore, clinical trials investigating new treatments in ADHD should include assessments at follow-up as their primary endpoint rather than assessments at outtake. Furthermore, an implication requiring further study is that neurofeedback could be stopped when SOI is normalized, which might result in fewer sessions. PMID:23099283

  4. Psychomotor Vigilance Testing of Professional Drivers in the Occupational Health Clinic: a Potential Objective Screen for Daytime Sleepiness

    PubMed Central

    Zhang, Chunbai; Varvarigou, Vasileia; Parks, Philip D.; Gautam, Shiva; Bueno, Antonio Vela; Malhotra, Atul; Kales, Stefanos N.

    2013-01-01

    Objective Psychomotor vigilance testing (PVT) rapidly assesses attention, reaction time (RT) and abnormal vigilance. Thus, PVT may be an adjunct to screening drivers for high risk obstructive sleep apnea (OSA)/excess daytime sleepiness (EDS). Methods Commercial drivers and emergency responders undergoing occupational examinations took a 10-minute PVT and were instructed to achieve their fastest possible RTs. Participants with maximum RT >5 seconds or ≥2 “super lapses” (RT ≥1000ms) were categorized as “microsleepers”. Results Among 193 male participants, the 15 microsleepers (8%) were significantly more obese, but not different on age or Epworth Sleepiness Score. Time of day had no effect on RT. Conclusion PVT is suitable to occupational clinics and can identify otherwise unrecognized, impaired vigilance. Further studies must validate the PVT abnormalities most predictive of OSA/EDS and vehicular crashes, compared to adiposity measures alone. PMID:21826029

  5. [Ketamine racemate or S-(+)-ketamine and midazolam. The effect on vigilance, efficacy and subjective findings].

    PubMed

    Doenicke, A; Kugler, J; Mayer, M; Angster, R; Hoffmann, P

    1992-10-01

    Ketamine is a racemic mixture containing equal amounts of optical isomers that have almost identical pharmacokinetic properties but different pharmacodynamic effects. The S-(+)-isomer of ketamine has about twice the anaesthetic and analgesic potency of the racemic ketamine preparation and is judged to induce less psychic emergence reactions and to be followed by a more rapid recovery of vigilance. The present study was designed to assess whether the S-(+)-isomer of ketamine is superior to the racemic mixture in cardiovascular characteristics, emergence reactions and cognitive functions, and whether side effects may be reduced or prevented by administration of midazolam prior to injection of S-(+)-ketamine. METHODS. Following ethics committee approval and informed consent, 30 volunteers were randomly allocated in this double-blind study to three groups of 10 each. Group 1 received 2 mg/kg bw racemic ketamine, group 2, 1 mg/kg bw S-(+)-ketamine and group 3, 1 mg/kg bw S-(+)-ketamine after premedication with 0.1 mg/kg midazolam i.v. Cardiovascular changes, state of vigilance, cognitive performance, subjective mood and acceptance of anaesthesia were assessed by means of haemodynamic routine monitoring, electroencephalography (EEG), psychometric tests and interview. RESULTS. The increases in mean arterial pressure and heart rate following the injection of racemic ketamine and S-(+)-ketamine were identical and the differences from baseline values significant after both. Premedication with midazolam ensured stable haemodynamics after injection of S-(+)-ketamine. EEG analysis displayed the characteristic changes well known from ketamine anaesthesia for both racemic and S-(+)-ketamine. The vigilosomnoscript showed an identical profile of vigilance up to 30 min after injection of both drugs. The vigilance status after 125 min was less impaired by S-(+)-ketamine than by racemic ketamine. Psychological assessment showed a prompter recovery of visual attentiveness and

  6. Relationship between the tonic elevator mandibular activity and the vertical dimension during the states of vigilance and hypnosis.

    PubMed

    Manns, A; Zuazola, R V; Sirhan, R M; Quiroz, M; Rocabado, M

    1990-04-01

    The variation of the tonic EMG elevator mandibular activity was studied as well as the consequent variation of the vertical dimension in two different experimental states: those of vigilance and hypnosis. In the state of vigilance, normal values of tonic EMG activity were recorded and a space of inocclusion (X = 2.22 mm) coincident with the postural mandibular position. Under hypnosis a significant reduction of the tonic EMG activity was observed (43 to 50%), together with a great increase of the inocclusion space (X = 8.90 mm). PMID:2073696

  7. Detecting spring after a long winter: coma or slow vigilance in cold, hypoxic turtles?

    PubMed Central

    Madsen, Jesper G.; Wang, Tobias; Beedholm, Kristian; Madsen, Peter T.

    2013-01-01

    Many freshwater turtle species can spend the winter submerged in ice-covered lakes by lowering their metabolism, and it has been proposed that such severe metabolic depression render these turtles comatose. This raises the question of how they can detect the arrival of spring and respond in a sensible way to sensory information during hibernation. Using evoked potentials from cold or hypoxic turtles exposed to vibration and light, we show that hibernating turtles maintain neural responsiveness to light stimuli during prolonged hypoxia. Furthermore, turtles held under hibernation conditions for 14 days increase their activity when exposed to light or elevated temperatures, but not to vibration or increased oxygen. It is concluded that hibernating turtles are not comatose, but remain vigilant during overwintering in cold hypoxia, allowing them to respond to the coming of spring and to adjust their behaviour to specific sensory inputs. PMID:24108677

  8. A simulator study of the interaction of pilot workload with errors, vigilance, and decisions

    NASA Technical Reports Server (NTRS)

    Smith, H. P. R.

    1979-01-01

    A full mission simulation of a civil air transport scenario that had two levels of workload was used to observe the actions of the crews and the basic aircraft parameters and to record heart rates. The results showed that the number of errors was very variable among crews but the mean increased in the higher workload case. The increase in errors was not related to rise in heart rate but was associated with vigilance times as well as the days since the last flight. The recorded data also made it possible to investigate decision time and decision order. These also varied among crews and seemed related to the ability of captains to manage the resources available to them on the flight deck.

  9. Crew Alertness Management on the Flight Deck: Cognitive and Vigilance Performance

    NASA Technical Reports Server (NTRS)

    Dinges, David F.

    1998-01-01

    This project had three broad goals: (1) to identify environmental and organismic risks to performance of long-haul cockpit crews; (2) to assess how cognitive and psychomotor vigilance performance, and subjective measures of alertness, were affected by work-rest schedules typical of long-haul cockpit crews; and (3) to determine the alertness-promoting effectiveness of behavioral and technological countermeasures to fatigue on the flight deck. During the course of the research, a number of studies were completed in cooperation with the NASA Ames Fatigue Countermeasures Program. The publications emerging from this project are listed in a bibliography in the appendix. Progress toward these goals will be summarized below according to the period in which it was accomplished.

  10. Validity and sensitivity of a brief psychomotor vigilance test (PVT-B) to total and partial sleep deprivation

    NASA Astrophysics Data System (ADS)

    Basner, Mathias; Mollicone, Daniel; Dinges, David F.

    2011-12-01

    The Psychomotor Vigilance Test (PVT) objectively assesses fatigue-related changes in alertness associated with sleep loss, extended wakefulness, circadian misalignment, and time on task. The standard 10-min PVT is often considered impractical in applied contexts. To address this limitation, we developed a modified brief 3-min version of the PVT (PVT-B). The PVT-B was validated in controlled laboratory studies with 74 healthy subjects (34 female, aged 22-45 years) that participated either in a total sleep deprivation (TSD) study involving 33 h awake ( N=31 subjects) or in a partial sleep deprivation (PSD) protocol involving 5 consecutive nights of 4 h time in bed ( N=43 subjects). PVT and PVT-B were performed regularly during wakefulness. Effect sizes of 5 key PVT outcomes were larger for TSD than PSD and larger for PVT than for PVT-B for all outcomes. Effect size was largest for response speed (reciprocal response time) for both the PVT-B and the PVT in both TSD and PSD. According to Cohen's criteria, effect sizes for the PVT-B were still large (TSD) or medium to large (PSD, except for fastest 10% RT). Compared to the 70% decrease in test duration the 22.7% (range 6.9-67.8%) average decrease in effect size was deemed an acceptable trade-off between duration and sensitivity. Overall, PVT-B performance had faster response times, more false starts and fewer lapses than PVT performance (all p<0.01). After reducing the lapse threshold from 500 to 355 ms for PVT-B, mixed model ANOVAs indicated no differential sensitivity to sleep loss between PVT-B and PVT for all outcome variables (all P>0.15) but the fastest 10% response times during PSD ( P<0.001), and effect sizes increased from 1.38 to 1.49 (TSD) and 0.65 to 0.76 (PSD), respectively. In conclusion, PVT-B tracked standard 10-min PVT performance throughout both TSD and PSD, and yielded medium to large effect sizes. PVT-B may be a useful tool for assessing behavioral alertness in settings where the duration of the 10

  11. How group size affects vigilance dynamics and time allocation patterns: the key role of imitation and tempo.

    PubMed

    Michelena, Pablo; Deneubourg, Jean-Louis

    2011-01-01

    In the context of social foraging, predator detection has been the subject of numerous studies, which acknowledge the adaptive response of the individual to the trade-off between feeding and vigilance. Typically, animals gain energy by increasing their feeding time and decreasing their vigilance effort with increasing group size, without increasing their risk of predation ('group size effect'). Research on the biological utility of vigilance has prevailed over considerations of the mechanistic rules that link individual decisions to group behavior. With sheep as a model species, we identified how the behaviors of conspecifics affect the individual decisions to switch activity. We highlight a simple mechanism whereby the group size effect on collective vigilance dynamics is shaped by two key features: the magnitude of social amplification and intrinsic differences between foraging and scanning bout durations. Our results highlight a positive correlation between the duration of scanning and foraging bouts at the level of the group. This finding reveals the existence of groups with high and low rates of transition between activities, suggesting individual variations in the transition rate, or 'tempo'. We present a mathematical model based on behavioral rules derived from experiments. Our theoretical predictions show that the system is robust in respect to variations in the propensity to imitate scanning and foraging, yet flexible in respect to differences in the duration of activity bouts. The model shows how individual decisions contribute to collective behavior patterns and how the group, in turn, facilitates individual-level adaptive responses. PMID:21525987

  12. Emotional attachment security as the origin of liberal-conservative differences in vigilance to negative features of the environment.

    PubMed

    Buck, Ross

    2014-06-01

    This commentary advances the hypothesis that differences between liberal and conservative orientations noted in the target article are emotional in nature and caused by differences in attachment security: Conservatives are more vigilant to negative features of the environment because of a general sense of insecurity, whereas liberals are relatively more secure. PMID:24970430

  13. Moonlight avoidance in gerbils reveals a sophisticated interplay among time allocation, vigilance and state-dependent foraging.

    PubMed

    Kotler, Burt P; Brown, Joel; Mukherjee, Shomen; Berger-Tal, Oded; Bouskila, Amos

    2010-05-22

    Foraging animals have several tools for managing the risk of predation, and the foraging games between them and their predators. Among these, time allocation is foremost, followed by vigilance and apprehension. Together, their use influences a forager's time allocation and giving-up density (GUD) in depletable resource patches. We examined Allenby's gerbils (Gerbilus andersoni allenbyi) exploiting seed resource patches in a large vivarium under varying moon phases in the presence of a red fox (Vulpes vulpes). We measured time allocated to foraging patches electronically and GUDs from seeds left behind in resource patches. From these, we estimated handling times, attack rates and quitting harvest rates (QHRs). Gerbils displayed greater vigilance (lower attack rates) at brighter moon phases (full < wane < wax < new). Similarly, they displayed higher GUDs at brighter moon phases (wax > full > new > wane). Finally, gerbils displayed higher QHRs at new and waxing moon phases. Differences across moon phases not only reflect changing time allocation and vigilance, but changes in the state of the foragers and their marginal value of energy. Early in the lunar cycle, gerbils rely on vigilance and sacrifice state to avoid risk; later they defend state at the cost of increased time allocation; finally their state can recover as safe opportunities expand. In the predator-prey foraging game, foxes may contribute to these patterns of behaviours by modulating their own activity in response to the opportunities presented in each moon phase. PMID:20053649

  14. How Group Size Affects Vigilance Dynamics and Time Allocation Patterns: The Key Role of Imitation and Tempo

    PubMed Central

    Michelena, Pablo; Deneubourg, Jean-Louis

    2011-01-01

    In the context of social foraging, predator detection has been the subject of numerous studies, which acknowledge the adaptive response of the individual to the trade-off between feeding and vigilance. Typically, animals gain energy by increasing their feeding time and decreasing their vigilance effort with increasing group size, without increasing their risk of predation (‘group size effect’). Research on the biological utility of vigilance has prevailed over considerations of the mechanistic rules that link individual decisions to group behavior. With sheep as a model species, we identified how the behaviors of conspecifics affect the individual decisions to switch activity. We highlight a simple mechanism whereby the group size effect on collective vigilance dynamics is shaped by two key features: the magnitude of social amplification and intrinsic differences between foraging and scanning bout durations. Our results highlight a positive correlation between the duration of scanning and foraging bouts at the level of the group. This finding reveals the existence of groups with high and low rates of transition between activies, suggesting individual variations in the transition rate, or ‘tempo’. We present a mathematical model based on behavioral rules derived from experiments. Our theoretical predictions show that the system is robust in respect to variations in the propensity to imitate scanning and foraging, yet flexible in respect to differences in the duration of activity bouts. The model shows how individual decisions contribute to collective behavior patterns and how the group, in turn, facilitates individual-level adaptive responses. PMID:21525987

  15. Moonlight avoidance in gerbils reveals a sophisticated interplay among time allocation, vigilance and state-dependent foraging

    PubMed Central

    Kotler, Burt P.; Brown, Joel; Mukherjee, Shomen; Berger-Tal, Oded; Bouskila, Amos

    2010-01-01

    Foraging animals have several tools for managing the risk of predation, and the foraging games between them and their predators. Among these, time allocation is foremost, followed by vigilance and apprehension. Together, their use influences a forager's time allocation and giving-up density (GUD) in depletable resource patches. We examined Allenby's gerbils (Gerbilus andersoni allenbyi) exploiting seed resource patches in a large vivarium under varying moon phases in the presence of a red fox (Vulpes vulpes). We measured time allocated to foraging patches electronically and GUDs from seeds left behind in resource patches. From these, we estimated handling times, attack rates and quitting harvest rates (QHRs). Gerbils displayed greater vigilance (lower attack rates) at brighter moon phases (full < wane < wax < new). Similarly, they displayed higher GUDs at brighter moon phases (wax > full > new > wane). Finally, gerbils displayed higher QHRs at new and waxing moon phases. Differences across moon phases not only reflect changing time allocation and vigilance, but changes in the state of the foragers and their marginal value of energy. Early in the lunar cycle, gerbils rely on vigilance and sacrifice state to avoid risk; later they defend state at the cost of increased time allocation; finally their state can recover as safe opportunities expand. In the predator–prey foraging game, foxes may contribute to these patterns of behaviours by modulating their own activity in response to the opportunities presented in each moon phase. PMID:20053649

  16. Detecting Threat-Related Intentional Actions of Others: Effects of Image Quality, Response Mode, and Target Cuing on Vigilance

    ERIC Educational Resources Information Center

    Parasuraman, Raja; de Visser, Ewart; Clarke, Ellen; McGarry, W. Ryan; Hussey, Elizabeth; Shaw, Tyler; Thompson, James C.

    2009-01-01

    Three experiments examined the vigilance performance of participants watching videos depicting intentional actions of an individual's hand reaching for and grasping an object--involving transporting or using either a gun or a hairdryer--in order to detect infrequent threat-related actions. Participants indicated detection of target actions either…

  17. Does the Vigilance-Avoidance Gazing Behavior of Children with Separation Anxiety Disorder Change after Cognitive-Behavioral Therapy?

    ERIC Educational Resources Information Center

    In-Albon, Tina; Schneider, Silvia

    2012-01-01

    Cognitive biases are of interest in understanding the development of anxiety disorders. They also play a significant role during psychotherapy, where cognitive biases are modified in order to break the vicious cycle responsible for maintaining anxiety disorders. In a previous study, the vigilance-avoidance pattern was shown in children with…

  18. In-flight automatic detection of vigilance states using a single EEG channel.

    PubMed

    Sauvet, F; Bougard, C; Coroenne, M; Lely, L; Van Beers, P; Elbaz, M; Guillard, M; Leger, D; Chennaoui, M

    2014-12-01

    Sleepiness and fatigue can reach particularly high levels during long-haul overnight flights. Under these conditions, voluntary or even involuntary sleep periods may occur, increasing the risk of accidents. The aim of this study was to assess the performance of an in-flight automatic detection system of low-vigilance states using a single electroencephalogram channel. Fourteen healthy pilots voluntarily wore a miniaturized brain electrical activity recording device during long-haul flights ( 10 ±2.0 h, Atlantic 2 and Falcon 50 M, French naval aviation). No subject was disturbed by the equipment. Seven pilots experienced at least a period of voluntary ( 26.8 ±8.0 min, n = 4) or involuntary sleep (N1 sleep stage, 26.6 ±18.7 s, n = 7) during the flight. Automatic classification (wake/sleep) by the algorithm was made for 10-s epochs (O1-M2 or C3-M2 channel), based on comparison of means to detect changes in α, β, and θ relative power, or ratio [( α+θ)/β], or fuzzy logic fusion (α, β). Pertinence and prognostic of the algorithm were determined using epoch-by-epoch comparison with visual-scoring (two blinded readers, AASM rules). The best concordance between automatic detection and visual-scoring was observed within the O1-M2 channel, using the ratio [( α+θ )/β] ( 98.3 ±4.1% of good detection, K = 0.94 ±0.07, with a 0.04 ±0.04 false positive rate and a 0.87 ±0.10 true positive rate). Our results confirm the efficiency of a miniaturized single electroencephalographic channel recording device, associated with an automatic detection algorithm, in order to detect low-vigilance states during real flights. PMID:24967979

  19. Electrophysiological correlates of behavioural changes in vigilance in vegetative state and minimally conscious state

    PubMed Central

    Landsness, Eric; Bruno, Marie-Aurélie; Noirhomme, Quentin; Riedner, Brady; Gosseries, Olivia; Schnakers, Caroline; Massimini, Marcello; Laureys, Steven

    2011-01-01

    The existence of normal sleep in patients in a vegetative state is still a matter of debate. Previous electrophysiological sleep studies in patients with disorders of consciousness did not differentiate patients in a vegetative state from patients in a minimally conscious state. Using high-density electroencephalographic sleep recordings, 11 patients with disorders of consciousness (six in a minimally conscious state, five in a vegetative state) were studied to correlate the electrophysiological changes associated with sleep to behavioural changes in vigilance (sustained eye closure and muscle inactivity). All minimally conscious patients showed clear electroencephalographic changes associated with decreases in behavioural vigilance. In the five minimally conscious patients showing sustained behavioural sleep periods, we identified several electrophysiological characteristics typical of normal sleep. In particular, all minimally conscious patients showed an alternating non-rapid eye movement/rapid eye movement sleep pattern and a homoeostatic decline of electroencephalographic slow wave activity through the night. In contrast, for most patients in a vegetative state, while preserved behavioural sleep was observed, the electroencephalographic patterns remained virtually unchanged during periods with the eyes closed compared to periods of behavioural wakefulness (eyes open and muscle activity). No slow wave sleep or rapid eye movement sleep stages could be identified and no homoeostatic regulation of sleep-related slow wave activity was observed over the night-time period. In conclusion, we observed behavioural, but no electrophysiological, sleep wake patterns in patients in a vegetative state, while there were near-to-normal patterns of sleep in patients in a minimally conscious state. These results shed light on the relationship between sleep electrophysiology and the level of consciousness in severely brain-damaged patients. We suggest that the study of sleep and

  20. Electrophysiological correlates of behavioural changes in vigilance in vegetative state and minimally conscious state.

    PubMed

    Landsness, Eric; Bruno, Marie-Aurélie; Noirhomme, Quentin; Riedner, Brady; Gosseries, Olivia; Schnakers, Caroline; Massimini, Marcello; Laureys, Steven; Tononi, Giulio; Boly, Mélanie

    2011-08-01

    The existence of normal sleep in patients in a vegetative state is still a matter of debate. Previous electrophysiological sleep studies in patients with disorders of consciousness did not differentiate patients in a vegetative state from patients in a minimally conscious state. Using high-density electroencephalographic sleep recordings, 11 patients with disorders of consciousness (six in a minimally conscious state, five in a vegetative state) were studied to correlate the electrophysiological changes associated with sleep to behavioural changes in vigilance (sustained eye closure and muscle inactivity). All minimally conscious patients showed clear electroencephalographic changes associated with decreases in behavioural vigilance. In the five minimally conscious patients showing sustained behavioural sleep periods, we identified several electrophysiological characteristics typical of normal sleep. In particular, all minimally conscious patients showed an alternating non-rapid eye movement/rapid eye movement sleep pattern and a homoeostatic decline of electroencephalographic slow wave activity through the night. In contrast, for most patients in a vegetative state, while preserved behavioural sleep was observed, the electroencephalographic patterns remained virtually unchanged during periods with the eyes closed compared to periods of behavioural wakefulness (eyes open and muscle activity). No slow wave sleep or rapid eye movement sleep stages could be identified and no homoeostatic regulation of sleep-related slow wave activity was observed over the night-time period. In conclusion, we observed behavioural, but no electrophysiological, sleep wake patterns in patients in a vegetative state, while there were near-to-normal patterns of sleep in patients in a minimally conscious state. These results shed light on the relationship between sleep electrophysiology and the level of consciousness in severely brain-damaged patients. We suggest that the study of sleep and

  1. Influence of 3 antivertiginous medications on the vigilance of healthy volunteers.

    PubMed

    Schneider, D; Kiessling, B; Wieczorek, M; Bognar-Steinberg, I; Schneider, L; Claussen, C F

    2003-04-01

    In the present randomized, comparative, double-blind, 3-way crossover study, possible effects of 3 antivertiginous medications on vigilance were investigated. 30 healthy volunteers received single doses of a fixed combination of cinnarizine 20 mg and dimenhydrinate 40 mg (Arlevert, ARL), dimenhydrinate 50 mg, or betahistine dimesylate 12 mg, in randomized order at 1-week intervals. Spontaneous brain electrical activity (EEG), acoustic late evoked potentials (ALEP) with P300, and reaction time were measured before and 90 (t90) and 180 minutes (t180) after drug intake. All 3 medications led to a delay of P300 (primary criterion) and a decrease of its amplitude. The maximum delay at t180 was found for dimenhydrinate (16.42 ms) and the lowest for betahistine (6.33 ms). Differences ARL vs dimenhydrinate and ARL vs betahistine were not statistically significant (p > 0.05). Spectral analysis of spontaneous EEG showed slight and similar decreases in the power in the a-band under dimenhydrinate and ARL (p = 0.07 and p = 0.03 with respect to baseline, respectively), but basically no change under betahistine. There was no effect on reaction time by either medication. None of the subjects reported drowsiness or any other adverse event. The findings confirm the reported suitability of P300 latency for measurement of drug effects on brain activity, but provide no indication of concomitant impairment of performance capacity by the tested drugs. Global assessment of the results suggests that the fixed combination cinnarizine 20 mg/dimenhydrinate 40 mg exerts only a minor effect on vigilance, not significantly different from betahistine, which is commonly regarded as a non-sedating antivertiginous drug PMID:12708605

  2. On the road to invariant recognition: explaining tradeoff and morph properties of cells in inferotemporal cortex using multiple-scale task-sensitive attentive learning.

    PubMed

    Grossberg, Stephen; Markowitz, Jeffrey; Cao, Yongqiang

    2011-12-01

    Visual object recognition is an essential accomplishment of advanced brains. Object recognition needs to be tolerant, or invariant, with respect to changes in object position, size, and view. In monkeys and humans, a key area for recognition is the anterior inferotemporal cortex (ITa). Recent neurophysiological data show that ITa cells with high object selectivity often have low position tolerance. We propose a neural model whose cells learn to simulate this tradeoff, as well as ITa responses to image morphs, while explaining how invariant recognition properties may arise in stages due to processes across multiple cortical areas. These processes include the cortical magnification factor, multiple receptive field sizes, and top-down attentive matching and learning properties that may be tuned by task requirements to attend to either concrete or abstract visual features with different levels of vigilance. The model predicts that data from the tradeoff and image morph tasks emerge from different levels of vigilance in the animals performing them. This result illustrates how different vigilance requirements of a task may change the course of category learning, notably the critical features that are attended and incorporated into learned category prototypes. The model outlines a path for developing an animal model of how defective vigilance control can lead to symptoms of various mental disorders, such as autism and amnesia. PMID:21665428

  3. The Impact of Target Frequency on Intra-Individual Variability in Euthymic Bipolar Disorder: A Comparison of Two Sustained Attention Tasks

    PubMed Central

    Moss, Rachel Ann; Finkelmeyer, Andreas; Robinson, Lucy J.; Thompson, Jill M.; Watson, Stuart; Ferrier, I. Nicol; Gallagher, Peter

    2016-01-01

    Greater intra-individual variability (IIV) in reaction time (RT) on a sustained attention task has been reported in patients with bipolar disorder (BD) compared with healthy controls. However, it is unclear whether IIV is task specific, or whether it represents general cross-task impairment in BD. This study aimed to investigate whether IIV occurs in sustained attention tasks with different parameters. Twenty-two patients with BD (currently euthymic) and 17 controls completed two sustained attention tasks on different occasions: a low target frequency (~20%) Vigil continuous performance test (CPT) and a high target frequency (~70%) CPT version A-X (CPT-AX). Variability measures (individual standard deviation and coefficient of variation) were calculated per participant, and ex-Gaussian modeling was also applied. This was supplemented by Vincentile analysis to characterize RT distributions. Results indicated that participants (patients and controls) were generally slower and more variable when completing the Vigil CPT compared with CPT-AX. Significant group differences were also observed in the Vigil CPT, with euthymic BD patients being more variable than controls. This result suggests that IIV in BD demonstrates some degree of task specificity. Further research should incorporate analysis of additional RT distributional models (drift diffusion and fast Fourier transform) to fully characterize the pattern of IIV in BD, as well as its relationship to cognitive processes. PMID:27378954

  4. Modeling simple driving tasks with a one-boundary diffusion model.

    PubMed

    Ratcliff, Roger; Strayer, David

    2014-06-01

    A one-boundary diffusion model was applied to the data from two experiments in which subjects were performing a simple simulated driving task. In the first experiment, the same subjects were tested on two driving tasks using a PC-based driving simulator and the psychomotor vigilance test. The diffusion model fit the response time distributions for each task and individual subject well. Model parameters were found to correlate across tasks, which suggests that common component processes were being tapped in the three tasks. The model was also fit to a distracted driving experiment of Cooper and Strayer (Human Factors, 50, 893-902, 2008). Results showed that distraction altered performance by affecting the rate of evidence accumulation (drift rate) and/or increasing the boundary settings. This provides an interpretation of cognitive distraction whereby conversing on a cell phone diverts attention from the normal accumulation of information in the driving environment. PMID:24297620

  5. Unconscious Vigilance: Worldview Defense Without Adaptations for Terror, Coalition, or Uncertainty Management

    PubMed Central

    Holbrook, Colin; Sousa, Paulo; Hahn-Holbrook, Jennifer

    2012-01-01

    Individuals subtly reminded of death, coalitional challenges, or feelings of uncertainty display exaggerated preferences for affirmations and against criticisms of their cultural in-groups. Terror management, coalitional psychology, and uncertainty management theories postulate this “worldview defense” effect as the output of mechanisms evolved either to allay the fear of death, foster social support, or reduce anxiety by increasing adherence to cultural values. In 4 studies, we report evidence for an alternative perspective. We argue that worldview defense owes to unconscious vigilance, a state of accentuated reactivity to affective targets (which need not relate to cultural worldviews) that follows detection of subtle alarm cues (which need not pertain to death, coalitional challenges, or uncertainty). In Studies 1 and 2, death-primed participants produced exaggerated ratings of worldview-neutral affective targets. In Studies 3 and 4, subliminal threat manipulations unrelated to death, coalitional challenges, or uncertainty evoked worldview defense. These results are discussed as they inform evolutionary interpretations of worldview defense and future investigations of the influence of unconscious alarm on judgment. PMID:21644809

  6. The scent of wolves: pyrazine analogs induce avoidance and vigilance behaviors in prey

    PubMed Central

    Osada, Kazumi; Miyazono, Sadaharu; Kashiwayanagi, Makoto

    2015-01-01

    The common gray wolf (Canis lupus) is an apex predator located at the top of the food chain in the Northern Hemisphere. It preys on rodents, rabbits, ungulates, and many other kinds of mammal. However, the behavioral evidence for, and the chemical basis of, the fear-inducing impact of wolf urine on prey are unclear. Recently, the pyrazine analogs 2, 6-dimethylpyrazine, 2, 3, 5-trimethylpyrazine and 3-ethyl-2, 5-dimethyl pyrazine were identified as kairomones in the urine of wolves. When mice were confronted with a mixture of purified pyrazine analogs, vigilance behaviors, including freezing and excitation of neurons at the accessory olfactory bulb, were markedly increased. Additionally, the odor of the pyrazine cocktail effectively suppressed the approach of deer to a feeding area, and for those close to the feeding area elicited fear-related behaviors such as the “tail-flag,” “flight,” and “jump” actions. In this review, we discuss the transfer of chemical information from wolf to prey through the novel kairomones identified in wolf urine and also compare the characteristics of wolf kairomones with other predator-produced kairomones that affect rodents. PMID:26500485

  7. Biological Rhythms Modelisation of Vigilance and Sleep in Microgravity State with COSINOR and Volterra's Kernels Methods

    NASA Astrophysics Data System (ADS)

    Gaudeua de Gerlicz, C.; Golding, J. G.; Bobola, Ph.; Moutarde, C.; Naji, S.

    2008-06-01

    The spaceflight under microgravity cause basically biological and physiological imbalance in human being. Lot of study has been yet release on this topic especially about sleep disturbances and on the circadian rhythms (alternation vigilance-sleep, body, temperature...). Factors like space motion sickness, noise, or excitement can cause severe sleep disturbances. For a stay of longer than four months in space, gradual increases in the planned duration of sleep were reported. [1] The average sleep in orbit was more than 1.5 hours shorter than the during control periods on earth, where sleep averaged 7.9 hours. [2] Alertness and calmness were unregistered yield clear circadian pattern of 24h but with a phase delay of 4h.The calmness showed a biphasic component (12h) mean sleep duration was 6.4 structured by 3-5 non REM/REM cycles. Modelisations of neurophysiologic mechanisms of stress and interactions between various physiological and psychological variables of rhythms have can be yet release with the COSINOR method. [3

  8. Eager feelings and vigilant reasons: Regulatory focus differences in judging moral wrongs.

    PubMed

    Cornwell, James F M; Higgins, E Tory

    2016-03-01

    For over a decade, moral psychologists have been actively researching the processes underlying moral judgments that are made intuitively without reference to an action's concrete harms or injustice, such as the well-known case of nonprocreative, consensual incest. We suggest that the reason some judge such scenarios as wrong (using intuitive feelings) and others do not (using deliberative reasons) is due to an important motivational distinction. Consistent with this view, across 7 studies, we demonstrate that negative judgments of such moral scenarios are more intense when processed in the promotion focus compared to the prevention focus, and that this is due to differences in whether eager (intuitive feelings) versus vigilant (deliberative reasons) means are employed in judging these moral wrongs. By examining both boundary conditions and possible underlying mechanisms for regulatory focus differences in moral judgment intensity, we expand our understanding of the differences between promotion and prevention regarding how proscriptive judgments are processed, while integrating these differences with existing theories in moral psychology. PMID:26726912

  9. The scent of wolves: pyrazine analogs induce avoidance and vigilance behaviors in prey.

    PubMed

    Osada, Kazumi; Miyazono, Sadaharu; Kashiwayanagi, Makoto

    2015-01-01

    The common gray wolf (Canis lupus) is an apex predator located at the top of the food chain in the Northern Hemisphere. It preys on rodents, rabbits, ungulates, and many other kinds of mammal. However, the behavioral evidence for, and the chemical basis of, the fear-inducing impact of wolf urine on prey are unclear. Recently, the pyrazine analogs 2, 6-dimethylpyrazine, 2, 3, 5-trimethylpyrazine and 3-ethyl-2, 5-dimethyl pyrazine were identified as kairomones in the urine of wolves. When mice were confronted with a mixture of purified pyrazine analogs, vigilance behaviors, including freezing and excitation of neurons at the accessory olfactory bulb, were markedly increased. Additionally, the odor of the pyrazine cocktail effectively suppressed the approach of deer to a feeding area, and for those close to the feeding area elicited fear-related behaviors such as the "tail-flag," "flight," and "jump" actions. In this review, we discuss the transfer of chemical information from wolf to prey through the novel kairomones identified in wolf urine and also compare the characteristics of wolf kairomones with other predator-produced kairomones that affect rodents. PMID:26500485

  10. Dark/light transition and vigilance states modulate jaw-closing muscle activity level in mice.

    PubMed

    Katayama, Keisuke; Mochizuki, Ayako; Kato, Takafumi; Ikeda, Minako; Ikawa, Yasuha; Nakamura, Shiro; Nakayama, Kiyomi; Wakabayashi, Noriyuki; Baba, Kazuyoshi; Inoue, Tomio

    2015-12-01

    Bruxism is associated with an increase in the activity of the jaw-closing muscles during sleep and wakefulness. However, the changes in jaw-closing muscle activity across states of vigilance over a 24-h period are unclear. In this study, we investigated the effects of dark/light transition and sleep/wake state on EMG activity of the masseter (jaw-closing) muscle in comparison with the activity of the upper trapezius muscle (a neck muscle) over a 24-h period in mice. The activities of the masseter and neck muscles during wakefulness were much greater than during non-REM and REM sleep. In contrast, the activities of both muscles slightly, but significantly, decreased during the transition period from dark to light. Histograms of masseter activity during wakefulness and non-REM sleep showed bimodal distributions, whereas the neck muscle showed unimodal activation in all states. These results suggest that the activities of jaw-closing and neck muscles are modulated by both sleep/wake state and dark/light transition, with the latter being to a lesser degree. Furthermore, even during non-REM sleep, jaw-closing muscles display bimodal activation, which may contribute to the occurrence of exaggerated aberrant muscle activity, such as sleep bruxism. PMID:26188127

  11. Unconscious vigilance: worldview defense without adaptations for terror, coalition, or uncertainty management.

    PubMed

    Holbrook, Colin; Sousa, Paulo; Hahn-Holbrook, Jennifer

    2011-09-01

    Individuals subtly reminded of death, coalitional challenges, or feelings of uncertainty display exaggerated preferences for affirmations and against criticisms of their cultural in-groups. Terror management, coalitional psychology, and uncertainty management theories postulate this "worldview defense" effect as the output of mechanisms evolved either to allay the fear of death, foster social support, or reduce anxiety by increasing adherence to cultural values. In 4 studies, we report evidence for an alternative perspective. We argue that worldview defense owes to unconscious vigilance, a state of accentuated reactivity to affective targets (which need not relate to cultural worldviews) that follows detection of subtle alarm cues (which need not pertain to death, coalitional challenges, or uncertainty). In Studies 1 and 2, death-primed participants produced exaggerated ratings of worldview-neutral affective targets. In Studies 3 and 4, subliminal threat manipulations unrelated to death, coalitional challenges, or uncertainty evoked worldview defense. These results are discussed as they inform evolutionary interpretations of worldview defense and future investigations of the influence of unconscious alarm on judgment. (PsycINFO Database Record (c) 2011 APA, all rights reserved). PMID:21644809

  12. Circadian rhythms (temperature, heart rate, vigilance, mood) of short and long sleepers: effects of sleep deprivation.

    PubMed

    Benoit, O; Foret, J; Merle, B; Reinberg, A

    1981-01-01

    Seven long sleepers (LS) (sleep greater than or equal to 9 h) and seven short sleepers (SS) (sleep less than or equal to 7 h), aged 20 to 23 years, were selected among medical students. They measured their axillary temperature (T), heart rate (HR) and self-estimated their vigilance (V) and mood (M) every 4 h from awakening to bed time during a ten-day control span and during the two sleep deprived nights. Polygraphic sleep recordings were performed on 3 control days and recovery from 24 h (day sleep) or 36 h (night sleep) sleep deprivations. For the 4 variables (T, HR, V and M), group circadian patterns were analyzed by means of the cosinor method for the control span and after both types of sleep deprivation. The acrophases of the 4 variables clustered more in LS than in SS. The acrophases of V and M were found to be more closely related to the sleep/wake rhythm than those of T and HR. Sleep deprivation resulted in a large change of the circadian rhythms in LS but had little effect in SS as indicated by the non detection of most acrophases in LS and the persistence of such acrophases in SS. This difference might be explained by the large interindividual variability of changes induced by the sleep deprivation in LS. Moreover, day sleep recovery was more disturbed in LS than in SS. PMID:7327054

  13. Psychomotor vigilance performance predicted by Epworth Sleepiness Scale scores in an operational setting with the United States Navy.

    PubMed

    Shattuck, Nita Lewis; Matsangas, Panagiotis

    2015-04-01

    It is critical in operational environments to identify individuals who are at higher risk of psychomotor performance impairments. This study assesses the utility of the Epworth Sleepiness Scale for predicting degraded psychomotor vigilance performance in an operational environment. Active duty crewmembers of a USA Navy destroyer (N = 69, age 21-54 years) completed the Epworth Sleepiness Scale at the beginning of the data collection period. Participants wore actigraphs and completed sleep diaries for 11 days. Psychomotor vigilance tests were administered throughout the data collection period using a 3-min version of the psychomotor vigilance test on the actigraphs. Crewmembers with elevated scores on the Epworth Sleepiness Scale (i.e. Epworth Sleepiness Scale >10) had 60% slower reaction times on average, and experienced at least 60% more lapses and false starts compared with individuals with normal Epworth Sleepiness Scale scores (i.e. Epworth Sleepiness Scale ≤ 10). Epworth Sleepiness Scale scores were correlated with daily time in bed (P < 0.01), sleep (P < 0.05), mean reaction time (P < 0.001), response speed 1/reaction time (P < 0.05), slowest 10% of response speed (P < 0.001), lapses (P < 0.01), and the sum of lapses and false starts (P < 0.001). In this chronically sleep-deprived population, elevated Epworth Sleepiness Scale scores identified that subset of the population who experienced degraded psychomotor vigilance performance. We theorize that Epworth Sleepiness Scale scores are an indication of personal sleep debt that varies depending on one's individual sleep requirement. In the absence of direct performance metrics, we also advocate that the Epworth Sleepiness Scale can be used to determine the prevalence of excessive sleepiness (and thereby assess the risk of performance decrements). PMID:25273376

  14. Exploring the evolution of a trade-off between vigilance and foraging in group-living organisms

    PubMed Central

    Olson, Randal S.; Haley, Patrick B.; Dyer, Fred C.; Adami, Christoph

    2015-01-01

    Even though grouping behaviour has been actively studied for over a century, the relative importance of the numerous proposed fitness benefits of grouping remain unclear. We use a digital model of evolving prey under simulated predation to directly explore the evolution of gregarious foraging behaviour according to one such benefit, the ‘many eyes’ hypothesis. According to this hypothesis, collective vigilance allows prey in large groups to detect predators more efficiently by making alarm signals or behavioural cues to each other, thereby allowing individuals within the group to spend more time foraging. Here, we find that collective vigilance is sufficient to select for gregarious foraging behaviour as long there is not a direct cost for grouping (e.g. competition for limited food resources), even when controlling for confounding factors such as the dilution effect. Furthermore, we explore the role of the genetic relatedness and reproductive strategy of the prey and find that highly related groups of prey with a semelparous reproductive strategy are the most likely to evolve gregarious foraging behaviour mediated by the benefit of vigilance. These findings, combined with earlier studies with evolving digital organisms, further sharpen our understanding of the factors favouring grouping behaviour. PMID:26473039

  15. A Vehicle Active Safety Model: Vehicle Speed Control Based on Driver Vigilance Detection Using Wearable EEG and Sparse Representation

    PubMed Central

    Zhang, Zutao; Luo, Dianyuan; Rasim, Yagubov; Li, Yanjun; Meng, Guanjun; Xu, Jian; Wang, Chunbai

    2016-01-01

    In this paper, we present a vehicle active safety model for vehicle speed control based on driver vigilance detection using low-cost, comfortable, wearable electroencephalographic (EEG) sensors and sparse representation. The proposed system consists of three main steps, namely wireless wearable EEG collection, driver vigilance detection, and vehicle speed control strategy. First of all, a homemade low-cost comfortable wearable brain-computer interface (BCI) system with eight channels is designed for collecting the driver’s EEG signal. Second, wavelet de-noising and down-sample algorithms are utilized to enhance the quality of EEG data, and Fast Fourier Transformation (FFT) is adopted to extract the EEG power spectrum density (PSD). In this step, sparse representation classification combined with k-singular value decomposition (KSVD) is firstly introduced in PSD to estimate the driver’s vigilance level . Finally, a novel safety strategy of vehicle speed control, which controls the electronic throttle opening and automatic braking after driver fatigue detection using the above method, is presented to avoid serious collisions and traffic accidents. The simulation and practical testing results demonstrate the feasibility of the vehicle active safety model. PMID:26907278

  16. A Vehicle Active Safety Model: Vehicle Speed Control Based on Driver Vigilance Detection Using Wearable EEG and Sparse Representation.

    PubMed

    Zhang, Zutao; Luo, Dianyuan; Rasim, Yagubov; Li, Yanjun; Meng, Guanjun; Xu, Jian; Wang, Chunbai

    2016-01-01

    In this paper, we present a vehicle active safety model for vehicle speed control based on driver vigilance detection using low-cost, comfortable, wearable electroencephalographic (EEG) sensors and sparse representation. The proposed system consists of three main steps, namely wireless wearable EEG collection, driver vigilance detection, and vehicle speed control strategy. First of all, a homemade low-cost comfortable wearable brain-computer interface (BCI) system with eight channels is designed for collecting the driver's EEG signal. Second, wavelet de-noising and down-sample algorithms are utilized to enhance the quality of EEG data, and Fast Fourier Transformation (FFT) is adopted to extract the EEG power spectrum density (PSD). In this step, sparse representation classification combined with k-singular value decomposition (KSVD) is firstly introduced in PSD to estimate the driver's vigilance level. Finally, a novel safety strategy of vehicle speed control, which controls the electronic throttle opening and automatic braking after driver fatigue detection using the above method, is presented to avoid serious collisions and traffic accidents. The simulation and practical testing results demonstrate the feasibility of the vehicle active safety model. PMID:26907278

  17. Diffusion model for one-choice reaction-time tasks and the cognitive effects of sleep deprivation.

    PubMed

    Ratcliff, Roger; Van Dongen, Hans P A

    2011-07-01

    One-choice reaction-time (RT) tasks are used in many domains, including assessments of motor vehicle driving and assessments of the cognitive/behavioral consequences of sleep deprivation. In such tasks, subjects are asked to respond when they detect the onset of a stimulus; the dependent variable is RT. We present a cognitive model for one-choice RT tasks that uses a one-boundary diffusion process to represent the accumulation of stimulus information. When the accumulated evidence reaches a decision criterion, a response is initiated. This model is distinct in accounting for the RT distributions observed for one-choice RT tasks, which can have long tails that have not been accurately captured by earlier cognitive modeling approaches. We show that the model explains performance on a brightness-detection task (a "simple RT task") and on a psychomotor vigilance test. The latter is used extensively to examine the clinical and behavioral effects of sleep deprivation. For the brightness-detection task, the model explains the behavior of RT distributions as a function of brightness. For the psychomotor vigilance test, it accounts for lapses in performance under conditions of sleep deprivation and for changes in the shapes of RT distributions over the course of sleep deprivation. The model also successfully maps the rate of accumulation of stimulus information onto independently derived predictions of alertness. The model is a unified, mechanistic account of one-choice RT under conditions of sleep deprivation. PMID:21690336

  18. Heart rate variability and cognitive processing: The autonomic response to task demands.

    PubMed

    Luque-Casado, Antonio; Perales, José C; Cárdenas, David; Sanabria, Daniel

    2016-01-01

    This study investigated variations in heart rate variability (HRV) as a function of cognitive demands. Participants completed an execution condition including the psychomotor vigilance task, a working memory task and a duration discrimination task. The control condition consisted of oddball versions (participants had to detect the rare event) of the tasks from the execution condition, designed to control for the effect of the task parameters (stimulus duration and stimulus rate) on HRV. The NASA-TLX questionnaire was used as a subjective measure of cognitive workload across tasks and conditions. Three major findings emerged from this study. First, HRV varied as a function of task demands (with the lowest values in the working memory task). Second, and crucially, we found similar HRV values when comparing each of the tasks with its oddball control equivalent, and a significant decrement in HRV as a function of time-on-task. Finally, the NASA-TLX results showed larger cognitive workload in the execution condition than in the oddball control condition, and scores variations as a function of task. Taken together, our results suggest that HRV is highly sensitive to overall demands of sustained attention over and above the influence of other cognitive processes suggested by previous literature. In addition, our study highlights a potential dissociation between objective and subjective measures of mental workload, with important implications in applied settings. PMID:26638762

  19. Vigilance states, EEG spectra, and cortical temperature in the guinea pig.

    PubMed

    Tobler, I; Franken, P; Jaggi, K

    1993-06-01

    Vigilance states, electroencephalogram (EEG) power spectra (0.25-25.0 Hz), and cortical temperature (TCRT) were obtained in nine guinea pigs for 24 h in a 12:12-h light-dark (LD 12:12) schedule. Sleep was markedly polyphasic and fragmented and amounted to 32% of recording time, which is a low value compared with sleep in other rodents. There was 6.8% more sleep in the light period than in the dark period. EEG power density in non-rapid eye movement (NREM) sleep showed no significant temporal trend within the light or the dark period. The homeostatic aspects of sleep regulation, as proposed in the two-process model, can account for the slow-wave activity (SWA) pattern also in the guinea pig: The small 24-h amplitude of the sleep-wakefulness pattern resulted in a small, 12% decline of SWA within the light period. In contrast to more distinctly nocturnal rodents, SWA in the dark period was not higher than in the light period. TCRT showed no difference between the light and the dark period. TCRT in REM sleep and waking was higher than TCRT in NREM sleep. TCRT increased after the transition from NREM sleep to either REM sleep or waking, and decreased in the last minute before the transition and after the transition from waking to NREM sleep. Motor activity measured in six animals for 11 days in constant darkness showed no apparent rhythm in three animals and a significant circadian rhythm in three others. Our data support the notion that guinea pigs exhibit only a weak circadian rest-activity rhythm. PMID:8322965

  20. Clinical Relevance of Disturbances of Sleep and Vigilance in Major Depressive Disorder: A Review

    PubMed Central

    Murck, Harald; Post, Anke

    2010-01-01

    Objective: The primary objective of this article is to provide a concise review of the clinical relevance of sleep and vigilance in major depressive disorder. Data Sources: PubMed was reviewed (1990–2009) and English-language articles were identified using the key words sleep and depression and sleep and antidepressants. Secondary searches included articles cited in sources identified by the primary search. Study Selection: The narrative review provides brief descriptions of the normal physiology of sleep and changes associated with depression, as well as the impact of various treatments on these processes. Data Synthesis: Although it has long been known that sleep disturbances are an important characteristic of depression, relatively few studies have been conducted with the newer-generation antidepressants. Neither of the most widely used classes of antidepressants, the selective serotonin reuptake inhibitors and the serotonin-norepinephrine reuptake inhibitors, have particularly beneficial effects on sleep and, among the medications that reliably improve sleep efficiency, including mirtazapine and the tricyclic antidepressants, problems with daytime sedation can offset therapeutic benefit. Despite relatively widespread use, trazodone has not been demonstrated to be an effective and safe hypnotic in patients taking other antidepressants. For many patients, ongoing concomitant treatment with benzodiazepines and related drugs is the preferred option, again without convincing empirical support of longer-term efficacy. Among newer and investigational antidepressants, agomelatine shows promise with respect to both overall safety and effects on insomnia, although possible negative effects on liver function warrant further study. Conclusions: Sleep disturbances are a significant aspect of depressive syndromes, and relief of insomnia remains an important unmet need in antidepressant therapeutics. Development of a well-tolerated antidepressant medication that rapidly

  1. AAVPG: A vigilant vector where transgene expression is induced by p53

    SciTech Connect

    Bajgelman, Marcio C.; Medrano, Ruan F.V.; Carvalho, Anna Carolina P.V.; Strauss, Bryan E.

    2013-12-15

    Using p53 to drive transgene expression from viral vectors may provide on demand expression in response to physiologic stress, such as hypoxia or DNA damage. Here we introduce AAVPG, an adeno-associated viral (AAV) vector where a p53-responsive promoter, termed PG, is used to control transgene expression. In vitro assays show that expression from the AAVPG-luc vector was induced specifically in the presence of functional p53 (1038±202 fold increase, p<0.001). The AAVPG-luc vector was an effective biosensor of p53 activation in response to hypoxia (4.48±0.6 fold increase in the presence of 250 µM CoCl{sub 2}, p<0.001) and biomechanical stress (2.53±0.4 fold increase with stretching, p<0.05). In vivo, the vigilant nature of the AAVPG-luc vector was revealed after treatment of tumor-bearing mice with doxorubicin (pre-treatment, 3.4×10{sup 5}±0.43×10{sup 5} photons/s; post-treatment, 6.6×10{sup 5}±2.1×10{sup 5} photons/s, p<0.05). These results indicate that the AAVPG vector is an interesting option for detecting p53 activity both in vitro and in vivo. - Highlights: • AAV vector where transgene expression is controlled by the tumor suppressor p53. • The new vector, AAVPG, shown to function as a biosensor of p53 activity, in vitro and in vivo. • The p53 activity monitored by the AAVPG vector is relevant to cancer and other diseases. • AAVPG reporter gene expression was activated upon DNA damage, hypoxia and mechanical stress.

  2. A resource-control account of sustained attention: evidence from mind-wandering and vigilance paradigms.

    PubMed

    Thomson, David R; Besner, Derek; Smilek, Daniel

    2015-01-01

    Staying attentive is challenging enough when carrying out everyday tasks, such as reading or sitting through a lecture, and failures to do so can be frustrating and inconvenient. However, such lapses may even be life threatening, for example, if a pilot fails to monitor an oil-pressure gauge or if a long-haul truck driver fails to notice a car in his or her blind spot. Here, we explore two explanations of sustained-attention lapses. By one account, task monotony leads to an increasing preoccupation with internal thought (i.e., mind wandering). By another, task demands result in the depletion of information-processing resources that are needed to perform the task. A review of the sustained-attention literature suggests that neither theory, on its own, adequately explains the full range of findings. We propose a novel framework to explain why attention lapses as a function of time-on-task by combining aspects of two different theories of mind wandering: attentional resource (Smallwood & Schooler, 2006) and control failure (McVay & Kane, 2010). We then use our "resource-control" theory to explain performance decrements in sustained-attention tasks. We end by making some explicit predictions regarding mind wandering in general and sustained-attention performance in particular. PMID:25910383

  3. Cognitive Fatigue Influences Time-On-Task during Bodyweight Resistance Training Exercise

    PubMed Central

    Head, James R.; Tenan, Matthew S.; Tweedell, Andrew J.; Price, Thomas F.; LaFiandra, Michael E.; Helton, William S.

    2016-01-01

    Prior investigations have shown measurable performance impairments on continuous physical performance tasks when preceded by a cognitively fatiguing task. However, the effect of cognitive fatigue on bodyweight resistance training exercise task performance is unknown. In the current investigation 18 amateur athletes completed a full body exercise task preceded by either a cognitive fatiguing or control intervention. In a randomized repeated measure design, each participant completed the same exercise task preceded by a 52 min cognitively fatiguing intervention (vigilance) or control intervention (video). Data collection sessions were separated by 1 week. Participants rated the fatigue intervention with a significantly higher workload compared to the control intervention (p < 0.001). Additionally, participants self-reported significantly greater energetic arousal for cognitively fatiguing task (p = 0.02). Cognitive fatigue did not significantly impact number of repetitions completed during the exercise task (p = 0.77); however, when cognitively fatigued, participants had decreased percent time-on-task (57%) relative to the no fatigue condition (60%; p = 0.04). RPE significantly changed over time (p < 0.001), but failed to show significant differences between the cognitive fatigue intervention and control intervention (p > 0.05). There was no statistical difference for heart rate or metabolic expenditure as a function of fatigue intervention during exercise. Cognitively fatigued athletes have decreased time-on-task in bodyweight resistance training exercise tasks.

  4. Sex-Related Differences in the Trade-Off between Foraging and Vigilance in a Granivorous Forager

    PubMed Central

    Powolny, Thibaut; Bretagnolle, Vincent; Aguilar, Astrid; Eraud, Cyril

    2014-01-01

    The relationship between intake rate and food density can provide the foundation for models that predict the spatiotemporal distribution of organisms across a range of resource densities. The functional response, describing the relationship between resource density and intake rate is often interpreted mechanistically as the relationships between times spend searching and handling. While several functional response models incorporate anti-predator vigilance (defined here as an interruption of feeding or some other activity to visually scan the environment, directed mainly towards detecting potential predators), the impacts of environmental factors influencing directly anti-predator vigilance remains unclear. We examined the combined effects of different scenarios of predation risk and food density on time allocation between foraging and anti-predator vigilance in a granivorous species. We experimentally exposed Skylarks to various cover heights and seed densities, and measured individual time budget and pecking and intake rates. Our results indicated that time devoted to different activities varied as a function of both seed density and cover height. Foraging time increased with seed density for all cover heights. Conversely, an increased cover height resulted in a decreased foraging time. Contrary to males, the decreased proportion of time spent foraging did not translate into a foraging disadvantage for females. When vegetation height was higher, females maintained similar pecking and intake rates compared to intermediate levels, while males consistently decreased their energy gain. This difference in anti-predator responses suggests a sexually mediated strategy in the food-safety trade-off: when resource density is high a females would adopt a camouflage strategy while an escape strategy would be adopted by males. In other words, males would leave risky-areas, whereas females would stay when resource density is high. Our results suggest that increased predation

  5. Local Properties of Vigilance States: EMD Analysis of EEG Signals during Sleep-Waking States of Freely Moving Rats

    PubMed Central

    Kumar, Rupesh; Ramaswamy, Ram; Nath Mallick, Birendra

    2013-01-01

    Understanding the inherent dynamics of the EEG associated to sleep-waking can provide insights into its basic neural regulation. By characterizing the local properties of the EEG using power spectrum, empirical mode decomposition (EMD) and Hilbert-spectral analysis, we can examine the dynamics over a range of time-scales. We analyzed rat EEG during wake, NREMS and REMS using these methods. The average instantaneous phase, power spectral density (PSD) of intrinsic mode functions (IMFs) and the energy content in various frequency bands show characteristic changes in each of the vigilance states. The 2nd and 7th IMFs show changes in PSD for wake and REMS, suggesting that those modes may carry wake- and REMS-associated cognitive, conscious and behavior-specific information of an individual even though the EEG may appear similar. The energy content in θ2 (6Hz-9Hz) band of the 1st IMF for REMS is larger than that of wake. The decrease in the phase function of IMFs from wake to REMS to NREMS indicates decrease of the mean frequency in these states, respectively. The rate of information processing in waking state is more in the time scale described by the first three IMFs than in REMS state. However, for IMF5-IMF7, the rate is more for REMS than that for wake. We obtained Hilbert-Huang spectral entropy, which is a suitable measure of information processing in each of these state-specific EEG. It is possible to evaluate the complex dynamics of the EEG in each of the vigilance states by applying measures based on EMD and Hilbert-transform. Our results suggest that the EMD based nonlinear measures of the EEG can provide useful estimates of the information possessed by various oscillations associated with the vigilance states. Further, the EMD-based spectral measures may have implications in understanding anatamo-physiological correlates of sleep-waking behavior and clinical diagnosis of sleep-pathology. PMID:24167606

  6. Local properties of vigilance states: EMD analysis of EEG signals during sleep-waking states of freely moving rats.

    PubMed

    Kumar, Rupesh; Ramaswamy, Ram; Nath Mallick, Birendra

    2013-01-01

    Understanding the inherent dynamics of the EEG associated to sleep-waking can provide insights into its basic neural regulation. By characterizing the local properties of the EEG using power spectrum, empirical mode decomposition (EMD) and Hilbert-spectral analysis, we can examine the dynamics over a range of time-scales. We analyzed rat EEG during wake, NREMS and REMS using these methods. The average instantaneous phase, power spectral density (PSD) of intrinsic mode functions (IMFs) and the energy content in various frequency bands show characteristic changes in each of the vigilance states. The 2nd and 7th IMFs show changes in PSD for wake and REMS, suggesting that those modes may carry wake- and REMS-associated cognitive, conscious and behavior-specific information of an individual even though the EEG may appear similar. The energy content in θ2 (6 Hz-9 Hz) band of the 1st IMF for REMS is larger than that of wake. The decrease in the phase function of IMFs from wake to REMS to NREMS indicates decrease of the mean frequency in these states, respectively. The rate of information processing in waking state is more in the time scale described by the first three IMFs than in REMS state. However, for IMF5-IMF7, the rate is more for REMS than that for wake. We obtained Hilbert-Huang spectral entropy, which is a suitable measure of information processing in each of these state-specific EEG. It is possible to evaluate the complex dynamics of the EEG in each of the vigilance states by applying measures based on EMD and Hilbert-transform. Our results suggest that the EMD based nonlinear measures of the EEG can provide useful estimates of the information possessed by various oscillations associated with the vigilance states. Further, the EMD-based spectral measures may have implications in understanding anatamo-physiological correlates of sleep-waking behavior and clinical diagnosis of sleep-pathology. PMID:24167606

  7. Quantitative EEG Monitoring of Vigilance: Effects of Sleep Deprivation, Circadian Phase and Sympathetic Activation

    NASA Technical Reports Server (NTRS)

    Dijk, Derk-Jan

    1999-01-01

    Shuttle astronauts typically sleep only 6 to 6.5 hours per day while in orbit. This sleep loss is related to recurrent sleep cycle shifting--due to mission-dependent orbital mechanics and mission duration requirements-- and associated circadian displacement of sleep, the operational demands of space flight, noise and space motion sickness. Such sleep schedules are known to produce poor subjective sleep quality, daytime sleepiness, reduced attention, negative mood, slower reaction times, and impaired daytime alertness. Countermeasures to allow crew members to obtain an adequate amount of sleep and maintain adequate levels of neurobehavioral performance are being developed and investigated. However, it is necessary to develop methods that allow effective and attainable in-flight monitoring of vigilance to evaluate the effectiveness of these countermeasures and to detect and predict online critical decrements in alertness/performance. There is growing evidence to indicate that sleep loss and associated decrements in neurobehavioral function are reflected in the spectral composition of the electroencephalogram (EEG) during wakefulness as well as in the incidence of slow eye movements recorded by the electro-oculogram (EOG). Further-more, our preliminary data indicated that these changes in the EEG during wakefulness are more pronounced when subjects are in a supine posture, which mimics some of the physiologic effects of microgravity. Therefore, we evaluate the following hypotheses: (1) that during a 40-hour period of wakefulness (i.e., one night of total sleep deprivation) neurobehavioral function deteriorates, the incidence of slow eye-movements and EEG power density in the theta frequencies increases especially in frontal areas of the brain; (2) that the sleep deprivation induced deterioration of neurobehavioral function and changes in the incidence of slow eye movements and the spectral composition of the EEG are more pronounced when subjects are in a supine

  8. Task Definition: A Motivating Task = Eager Learners!

    ERIC Educational Resources Information Center

    Jansen, Barbara A.

    2005-01-01

    Teachers who design meaningful and developmentally appropriate tasks will motivate their students to engage in the content and as students work through the Big6 process, interacting with the content, they learn and practice information and technology skills. A valuable task definition technique is to develop questions that students in each group…

  9. Mean fecal glucocorticoid metabolites are associated with vigilance, whereas immediate cortisol levels better reflect acute anti-predator responses in meerkats.

    PubMed

    Voellmy, Irene K; Goncalves, Ines Braga; Barrette, Marie-France; Monfort, Steven L; Manser, Marta B

    2014-11-01

    Adrenal hormones likely affect anti-predator behavior in animals. With experimental field studies, we first investigated associations between mean fecal glucocorticoid metabolite (fGC) excretion and vigilance and with behavioral responses to alarm call playbacks in free-ranging meerkats (Suricata suricatta). We then tested how vigilance and behavioral responses to alarm call playbacks were affected in individuals administered exogenous cortisol. We found a positive association between mean fGC concentrations and vigilance behavior, but no relationship with the intensity of behavioral responses to alarm calls. However, in response to alarm call playbacks, individuals administered cortisol took slightly longer to resume foraging than control individuals treated with saline solution. Vigilance behavior, which occurs in the presence and absence of dangerous stimuli, serves to detect and avoid potential dangers, whereas responses to alarm calls serve to avoid immediate predation. Our data show that mean fGC excretion in meerkats was associated with vigilance, as a re-occurring anti-predator behavior over long time periods, and experimentally induced elevations of plasma cortisol affected the response to immediate threats. Together, our results indicate an association between the two types of anti-predator behavior and glucocorticoids, but that the underlying mechanisms may differ. Our study emphasizes the need to consider appropriate measures of adrenal activity specific to different contexts when assessing links between stress physiology and different anti-predator behaviors. PMID:25218254

  10. Novel analysis of sleep patterns in rats separates periods of vigilance cycling from long-duration wake events.

    PubMed

    Simasko, Steven M; Mukherjee, Sanjib

    2009-01-23

    Rats are polyphasic sleepers. However, a formal definition of when one sleep episode ends and another begins has not been put forth. In the present study we examine the distribution of wake episode durations and based on this distribution conclude there are multiple components of wake. If the wake episode exceeds 300 s the wake episode is assigned to long-duration wake (LDW), if the episode is less than 300 s it is assigned to brief wake (BW). Further support for this separation was found in close analysis of the EEG power spectrum in BW versus LDW. We then used LDW episodes to separate one sleep episode from another. We term the sleep episodes vigilance cycling (VC) because the rat is cycling between the vigilance states of BW, slow-wave sleep (SWS), and rapid-eye movement sleep (REMS). We find that the characteristics of VC are different in the light period versus the dark period. We further find that as VC episodes progress, SWS pressure lessens, but the amount of time spent in REMS increases. These findings suggest that VC episodes are regulated and meaningful to the sleep behavior of rats. The use of the concepts of LDW and VC provides additional insights into the description of sleep patterns in rats that may be important in the development of a complete description of sleep behavior in this animal. PMID:18835301

  11. Chronic Alcohol Treatment in Rats Alters Sleep by Fragmenting Periods of Vigilance Cycling in the Light Period with Extended Wakenings

    PubMed Central

    Mukherjee, Sanjib; Simasko, Steven M.

    2009-01-01

    Studies have shown that disturbed sleep produced by chronic alcohol abuse in humans can predict relapse drinking after periods of abstinence. How alcohol produces disturbed sleep remains unknown. In this study we used a novel analysis of sleep to examine the effects of alcohol on sleep patterns in rats. This analysis separates waking into multiple components and defines a period labeled vigilance cycling (VC) in which the rat rapidly cycles through various vigilance states. These VC episodes are separated by long duration wake periods (LDW). We find that 6 weeks of alcohol (6% in a liquid diet) caused fragmentation of extended VC episodes that normally occur in the light period. However, total daily amounts of slow-wave sleep (SWS) and rapid-eye movement sleep (REMS) remained constant. The daily amount of wake, SWS, and REMS remained constant because the alcohol treated rats increased the amount of VC in the dark period, and the sleep nature of VC in the dark period became more intense. In addition, we observed more wake and less REMS early in the light period in alcohol treated rats. All effects completely reversed by day 16 of alcohol withdrawal. Comparison of the effects of chronic alcohol to acute alcohol exposure demonstrated the effects of chronic alcohol are due to adaptation and not the acute presence of alcohol. The effects of chronic alcohol treatment in rats mimic the effects reported in humans (REMS suppression, difficulty falling asleep, and difficulty remaining asleep). PMID:19014977

  12. Novel Analysis of Sleep Patterns in Rats Separates Periods of Vigilance Cycling from Long Duration Wake Events

    PubMed Central

    Simasko, Steven M.; Mukherjee, Sanjib

    2009-01-01

    Rats are polyphasic sleepers. However, a formal definition of when one sleep episode ends and another begins has not been put forth. In the present study we examine the distribution of wake episode durations and based on this distribution conclude there are multiple components of wake. If the wake episode exceeds 300 sec the wake episode is assigned to long duration wake (LDW), if the episode is less than 300 sec it is assigned to brief wake (BW). Further support for this separation was found in close analysis of the EEG power spectrum in BW versus LDW. We then used LDW episodes to separate one sleep episode from another. We term the sleep episodes vigilance cycling (VC) because the rat is cycling between the vigilance states of brief wake (BW), slow-wave sleep (SWS), and rapid-eye movement sleep (REMS). We find that the characteristics of VC are different in the light period versus the dark period. We further find that as VC episodes progress, SWS pressure lessens, but the amount of time spent in REMS increases. These findings suggest that VC episodes are regulated and meaningful to the sleep behavior of rats. The use of the concepts of LDW and VC provides additional insights into the description of sleep patterns in rats that may be important in the development of a complete description of sleep behavior in this animal. PMID:18835301

  13. Trait rejection sensitivity is associated with vigilance and defensive response rather than detection of social rejection cues

    PubMed Central

    Kawamoto, Taishi; Nittono, Hiroshi; Ura, Mitsuhiro

    2015-01-01

    Prior studies suggest that psychological difficulties arise from higher trait Rejection Sensitivity (RS)—heightened vigilance and differential detection of social rejection cues and defensive response to. On the other hand, from an evolutionary perspective, rapid and efficient detection of social rejection cues can be considered beneficial. We conducted a survey and an electrophysiological experiment to reconcile this seeming contradiction. We compared the effects of RS and Rejection Detection Capability (RDC) on perceived interpersonal experiences (Study 1) and on neurocognitive processes in response to cues of social rejection (disgusted faces; Study 2). We found that RS and RDC were not significantly related, although RS was positively related to perceived social rejection experiences and RDC was positively related to perceived social inclusion experiences. Event-related brain potentials (ERPs) revealed that higher RS was related to cognitive avoidance (i.e., P1) and heightened motivated attention (i.e., late positive potential: LPP), but not to facial expression encoding (i.e., N170) toward disgusted faces. On the other hand, higher RDC was related to heightened N170 amplitude, but not to P1 and LPP amplitudes. These findings imply that sensitivity to rejection is apparently distinct from the ability to detect social rejection cues and instead reflects intense vigilance and defensive response to those cues. We discussed an alternative explanation of the relationship between RS and RDC from a signal detection perspective. PMID:26483750

  14. Functional Task Test (FTT)

    NASA Technical Reports Server (NTRS)

    Bloomberg, Jacob J.; Mulavara, Ajitkumar; Peters, Brian T.; Rescheke, Millard F.; Wood, Scott; Lawrence, Emily; Koffman, Igor; Ploutz-Snyder, Lori; Spiering, Barry A.; Feeback, Daniel L.; Platts, Steven H.; Stenger, Michael B.; Lee, Stuart M.C.; Arzeno, Natalia; Feiveson, Alan H.; Ryder, Jeffrey; Garcia, Yamil; Guilliams, Mark E.

    2009-01-01

    This slide presentation reviews the Functional Task Test (FTT), an interdisciplinary testing regimen that has been developed to evaluate astronaut postflight functional performance and related physiological changes. The objectives of the project are: (1) to develop a set of functional tasks that represent critical mission tasks for the Constellation Program, (2) determine the ability to perform these tasks after space flight, (3) Identify the key physiological factors that contribute to functional decrements and (4) Use this information to develop targeted countermeasures.

  15. Launching Complex Tasks

    ERIC Educational Resources Information Center

    Jackson, Kara J.; Shahan, Emily C.; Gibbons, Lynsey K.; Cobb, Paul A.

    2012-01-01

    Mathematics lessons can take a variety of formats. In this article, the authors discuss lessons organized around complex mathematical tasks. These lessons usually unfold in three phases. First, the task is introduced to students. Second, students work on solving the task. Third, the teacher "orchestrates" a concluding whole-class discussion in…

  16. Selecting Proportional Reasoning Tasks

    ERIC Educational Resources Information Center

    de la Cruz, Jessica A.

    2013-01-01

    With careful consideration given to task selection, students can construct their own solution strategies to solve complex proportional reasoning tasks while the teacher's instructional goals are still met. Several aspects of the tasks should be considered including their numerical structure, context, difficulty level, and the strategies they are…

  17. Task Time Tracker

    Energy Science and Technology Software Center (ESTSC)

    2013-07-24

    This client-side web app tracks the amount of time spent on arbitrary tasks. It allosw the creation of an unlimited number of arbitrarily named tasks ans via simple interactions, tracks the amount of time spent working on the drfined tasks.

  18. Grid Task Execution

    NASA Technical Reports Server (NTRS)

    Hu, Chaumin

    2007-01-01

    IPG Execution Service is a framework that reliably executes complex jobs on a computational grid, and is part of the IPG service architecture designed to support location-independent computing. The new grid service enables users to describe the platform on which they need a job to run, which allows the service to locate the desired platform, configure it for the required application, and execute the job. After a job is submitted, users can monitor it through periodic notifications, or through queries. Each job consists of a set of tasks that performs actions such as executing applications and managing data. Each task is executed based on a starting condition that is an expression of the states of other tasks. This formulation allows tasks to be executed in parallel, and also allows a user to specify tasks to execute when other tasks succeed, fail, or are canceled. The two core components of the Execution Service are the Task Database, which stores tasks that have been submitted for execution, and the Task Manager, which executes tasks in the proper order, based on the user-specified starting conditions, and avoids overloading local and remote resources while executing tasks.

  19. Relationship between Reaction Time, Fine Motor Control, and Visual-Spatial Perception on Vigilance and Visual-Motor Tasks in 22q11.2 Deletion Syndrome

    ERIC Educational Resources Information Center

    Howley, Sarah A.; Prasad, Sarah E.; Pender, Niall P.; Murphy, Kieran C.

    2012-01-01

    22q11.2 Deletion Syndrome (22q11DS) is a common microdeletion disorder associated with mild to moderate intellectual disability and specific neurocognitive deficits, particularly in visual-motor and attentional abilities. Currently there is evidence that the visual-motor profile of 22q11DS is not entirely mediated by intellectual disability and…

  20. The Correlation between Sex, Age, Educational Background, and Hours of Service on Vigilance Level of ATC Officers in Air Nav Surabaya, Indonesia

    ERIC Educational Resources Information Center

    Saleh, Lalu Muhammad; Suwandi, Tjipto; Hamidah

    2016-01-01

    The vigilance of an Air Traffic Control (ATC) officer determines aviation safety. The number of aviation accidents tends to be increasing in recent years. Aviation accidents may be caused by human errors (i.e. errors made by pilot or ATC officer) or unsafe work condition. Sex, age, educational background, and hours of service might affect…

  1. Now You Hear Me, Now You Don't: Eyelid Closures as an Indicator of Auditory Task Disengagement

    PubMed Central

    Ong, Ju Lynn; Asplund, Christopher L.; Chia, Tiffany T. Y.; Chee, Michael W. L.

    2013-01-01

    Study Objectives: Eyelid closures in fatigued individuals signify task disengagement in attention-demanding visual tasks. Here, we studied how varying degrees of eyelid closure predict responses to auditory stimuli depending on whether a participant is well rested or sleep deprived. We also examined time-on-task effects and how more and less vulnerable individuals differed in frequency of eye closures and lapses. Design: Six repetitions of an auditory vigilance task were performed in each of two sessions: rested wakefulness (RW) and total sleep deprivation (TSD) (order counterbalanced). Setting: Sleep laboratory. Participants: Nineteen healthy young adults (mean age: 22 ± 2.8 y; 11 males). Intervention: Approximately 24 h of TSD. Measurements and Results: Eyelid closure was rated on a 9-point scale (1 = fully closed to 9 = fully opened) using video segments time-locked to the auditory event. Eyes-open trials predominated during RW, but different degrees of eye closure were uniformly distributed during TSD. The frequency of lapses (response time > 800 ms or nonresponses) to auditory stimuli increased dramatically with greater degrees of eye closure, but the association was strong only during TSD. There were significant within-run time-on-task effects on eye closure and auditory lapses that were exacerbated by TSD. Participants who had more auditory lapses during TSD (more vulnerable) had greater variability in their eyelid closures. Conclusions: Eyelid closures are a strong predictor of auditory task disengagement in the sleep-deprived state but are less relevant during rested wakefulness. Individuals relatively more impaired in this auditory vigilance task during total sleep deprivation display oculomotor evidence for greater state instability. Citation: Ong JL; Asplund CL; Chia TTY; Chee MWL. Now you hear me, now you don't: eyelid closures as an indicator of auditory task disengagement. SLEEP 2013;36(12):1867-1874. PMID:24293761

  2. Factors affecting performance on a target monitoring task employing an automatic tracker.

    PubMed

    McFadden, Sharon M; Vimalachandran, Abhirami; Blackmore, Elizabeth

    2004-02-26

    The experiments in this paper examined the extent to which performance on a task employing an automatic tracker was similar to performance on tasks employing other types of automation that have been studied more extensively. Automated target tracking is being used in many sensor and navigation systems to improve performance and help the operator cope with increased data loads. With many automated systems these goals are not met. In particular, the operator often misses errors made by the automated system and may report no decrease in workload. Several hypotheses have been offered for the operator's failure to monitor an automated system adequately. These include lack of experience with the manual task, a vigilance decrement, complacency, and inappropriate level of automation. The relevance of each of these hypotheses to failure to monitor an automatic tracker adequately was examined. Performance and perceived workload on a target tracking task employing an automatic tracker, in which participants had to detect and then update the position of several targets (e.g. ships) at regular intervals, were measured as a function of number of targets, training with the manual task, experience, and time on task. The results suggested that failure to detect errors made by the automated system was due largely to the lack of visibility of the automation errors relative to other errors. However, complacency could not be ruled out entirely. Unlike some other tasks, the availability of a reliable automatic tracker did lead to a substantial reduction in perceived workload. PMID:14668161

  3. TNFα G308A polymorphism is associated with resilience to sleep deprivation-induced psychomotor vigilance performance impairment in healthy young adults.

    PubMed

    Satterfield, Brieann C; Wisor, Jonathan P; Field, Stephanie A; Schmidt, Michelle A; Van Dongen, Hans P A

    2015-07-01

    Cytokines such as TNFα play an integral role in sleep/wake regulation and have recently been hypothesized to be involved in cognitive impairment due to sleep deprivation. We examined the effect of a guanine to adenine substitution at position 308 in the TNFα gene (TNFα G308A) on psychomotor vigilance performance impairment during total sleep deprivation. A total of 88 healthy women and men (ages 22-40) participated in one of five laboratory total sleep deprivation experiments. Performance on a psychomotor vigilance test (PVT) was measured every 2-3h. The TNFα 308A allele, which is less common than the 308G allele, was associated with greater resilience to psychomotor vigilance performance impairment during total sleep deprivation (regardless of time of day), and also provided a small performance benefit at baseline. The effect of genotype on resilience persisted when controlling for between-subjects differences in age, gender, race/ethnicity, and baseline sleep duration. The TNFα G308A polymorphism predicted less than 10% of the overall between-subjects variance in performance impairment during sleep deprivation. Nonetheless, the differential effect of the polymorphism at the peak of performance impairment was more than 50% of median performance impairment at that time, which is sizeable compared to the effects of other genotypes reported in the literature. Our findings provided evidence for a role of TNFα in the effects of sleep deprivation on psychomotor vigilance performance. Furthermore, the TNFα G308A polymorphism may have predictive potential in a biomarker panel for the assessment of resilience to psychomotor vigilance performance impairment due to sleep deprivation. PMID:25542735

  4. TNFα G308A polymorphism is associated with resilience to sleep deprivation-induced psychomotor vigilance performance impairment in healthy young adults

    PubMed Central

    Satterfield, Brieann C.; Wisor, Jonathan P.; Field, Stephanie A.; Schmidt, Michelle A.; Van Dongen, Hans P.A.

    2015-01-01

    Cytokines such as TNFα play an integral role in sleep/wake regulation and have recently been hypothesized to be involved in cognitive impairment due to sleep deprivation. We examined the effect of a guanine to adenine substitution at position 308 in the TNFα gene (TNFα G308A) on psychomotor vigilance performance impairment during total sleep deprivation. A total of 88 healthy women and men (ages 22–40) participated in one of five laboratory total sleep deprivation experiments. Performance on a psychomotor vigilance test (PVT) was measured every 2 to 3 h. The TNFα 308A allele, which is less common than the 308G allele, was associated with greater resilience to psychomotor vigilance performance impairment during total sleep deprivation (regardless of time of day), and also provided a small performance benefit at baseline. The effect of genotype on resilience persisted when controlling for between-subjects differences in age, gender, race/ethnicity, and baseline sleep duration. The TNFα G308A polymorphism predicted less than 10% of the overall between-subjects variance in performance impairment during sleep deprivation. Nonetheless, the differential effect of the polymorphism at the peak of performance impairment was more than 50% of median performance impairment at that time, which is sizeable compared to the effects of other genotypes reported in the literature. Our findings provided evidence for a role of TNFα in the effects of sleep deprivation on psychomotor vigilance performance. Furthermore, the TNFα G308A polymorphism may have predictive potential in a biomarker panel for the assessment of resilience to psychomotor vigilance performance impairment due to sleep deprivation. PMID:25542735

  5. Automatic vigilance: the attention-grabbing power of approach- and avoidance-related social information.

    PubMed

    Wentura, D; Rothermund, K; Bak, P

    2000-06-01

    The automatic processing of information was investigated, varying valence (positive vs. negative) and relevance (other-relevant traits [ORT] vs. possessor-relevant traits [PRT]; G. Peeters, 1983) of stimuli. ORTs denote unconditionally positive or negative consequences for persons in the social environment of the holder of the trait (e.g., honest, brutal) whereas PRTs denote unconditionally positive or negative consequences for the trait holder (e.g., happy, depressive). In 2 experiments using the Stroop paradigm, larger interference effects were found for ORTs than PRTs. This is due to the behavior-relatedness of ORTs. In a go/no-go lexical decision task (Experiment 3), participants either had to withdraw their finger from a pressed key (i.e., "avoid") or had to press a key (i.e., "approach") if a word was presented. Responses to negative ORTs were relatively faster in the withdraw condition, whereas positive ORTs were relatively faster in the press condition. PMID:10870906

  6. NSI security task: Overview

    NASA Technical Reports Server (NTRS)

    Tencati, Ron

    1991-01-01

    An overview is presented of the NASA Science Internet (NSI) security task. The task includes the following: policies and security documentation; risk analysis and management; computer emergency response team; incident handling; toolkit development; user consulting; and working groups, conferences, and committees.

  7. Debugging tasked Ada programs

    NASA Technical Reports Server (NTRS)

    Fainter, R. G.; Lindquist, T. E.

    1986-01-01

    The applications for which Ada was developed require distributed implementations of the language and extensive use of tasking facilities. Debugging and testing technology as it applies to parallel features of languages currently falls short of needs. Thus, the development of embedded systems using Ada pose special challenges to the software engineer. Techniques for distributing Ada programs, support for simulating distributed target machines, testing facilities for tasked programs, and debugging support applicable to simulated and to real targets all need to be addressed. A technique is presented for debugging Ada programs that use tasking and it describes a debugger, called AdaTAD, to support the technique. The debugging technique is presented together with the use interface to AdaTAD. The component of AdaTAD that monitors and controls communication among tasks was designed in Ada and is presented through an example with a simple tasked program.

  8. Task Description Language

    NASA Technical Reports Server (NTRS)

    Simmons, Reid; Apfelbaum, David

    2005-01-01

    Task Description Language (TDL) is an extension of the C++ programming language that enables programmers to quickly and easily write complex, concurrent computer programs for controlling real-time autonomous systems, including robots and spacecraft. TDL is based on earlier work (circa 1984 through 1989) on the Task Control Architecture (TCA). TDL provides syntactic support for hierarchical task-level control functions, including task decomposition, synchronization, execution monitoring, and exception handling. A Java-language-based compiler transforms TDL programs into pure C++ code that includes calls to a platform-independent task-control-management (TCM) library. TDL has been used to control and coordinate multiple heterogeneous robots in projects sponsored by NASA and the Defense Advanced Research Projects Agency (DARPA). It has also been used in Brazil to control an autonomous airship and in Canada to control a robotic manipulator.

  9. Learning one task by interleaving practice with another task

    PubMed Central

    Szpiro, Sarit; Wright, Beverly A.; Carrasco, Marisa

    2014-01-01

    Perceptual learning is a sustainable improvement in performance on a perceptual task following training. A hallmark of perceptual learning is task specificity – after participants have trained on and learned a particular task, learning rarely transfers to another task, even with identical stimuli. Accordingly, it is assumed that performing a task throughout training is a requirement for learning to occur on that specific task. Thus, interleaving training trials of a target task, with those of another task, should not improve performance on the target task. However, recent findings in audition show that interleaving two tasks during training can facilitate perceptual learning, even when the training on neither task yields learning on its own. Here we examined the role of cross-task training in the visual domain by training 4 groups of human observers for 3 consecutive days on an orientation comparison task (target task) and/or spatial-frequency comparison task (interleaving task). Interleaving small amounts of training on each task, which were ineffective alone, not only enabled learning on the target orientation task, as in audition, but also surpassed the learning attained by training on that task alone for the same total number of trials. This study illustrates that cross-task training in visual perceptual learning can be more effective than single-task training. The results reveal a comparable learning principle across modalities and demonstrate how to optimize training regimens to maximize perceptual learning. PMID:24959653

  10. Independent task Fourier filters

    NASA Astrophysics Data System (ADS)

    Caulfield, H. John

    2001-11-01

    Since the early 1960s, a major part of optical computing systems has been Fourier pattern recognition, which takes advantage of high speed filter changes to enable powerful nonlinear discrimination in `real time.' Because filter has a task quite independent of the tasks of the other filters, they can be applied and evaluated in parallel or, in a simple approach I describe, in sequence very rapidly. Thus I use the name ITFF (independent task Fourier filter). These filters can also break very complex discrimination tasks into easily handled parts, so the wonderful space invariance properties of Fourier filtering need not be sacrificed to achieve high discrimination and good generalizability even for ultracomplex discrimination problems. The training procedure proceeds sequentially, as the task for a given filter is defined a posteriori by declaring it to be the discrimination of particular members of set A from all members of set B with sufficient margin. That is, we set the threshold to achieve the desired margin and note the A members discriminated by that threshold. Discriminating those A members from all members of B becomes the task of that filter. Those A members are then removed from the set A, so no other filter will be asked to perform that already accomplished task.

  11. Spontaneous eyelid closures link vigilance fluctuation with fMRI dynamic connectivity states

    PubMed Central

    Wang, Chenhao; Ong, Ju Lynn; Patanaik, Amiya; Chee, Michael W. L.

    2016-01-01

    Fluctuations in resting-state functional connectivity occur but their behavioral significance remains unclear, largely because correlating behavioral state with dynamic functional connectivity states (DCS) engages probes that disrupt the very behavioral state we seek to observe. Observing spontaneous eyelid closures following sleep deprivation permits nonintrusive arousal monitoring. During periods of low arousal dominated by eyelid closures, sliding-window correlation analysis uncovered a DCS associated with reduced within-network functional connectivity of default mode and dorsal/ventral attention networks, as well as reduced anticorrelation between these networks. Conversely, during periods when participants’ eyelids were wide open, a second DCS was associated with less decoupling between the visual network and higher-order cognitive networks that included dorsal/ventral attention and default mode networks. In subcortical structures, eyelid closures were associated with increased connectivity between the striatum and thalamus with the ventral attention network, and greater anticorrelation with the dorsal attention network. When applied to task-based fMRI data, these two DCS predicted interindividual differences in frequency of behavioral lapsing and intraindividual temporal fluctuations in response speed. These findings with participants who underwent a night of total sleep deprivation were replicated in an independent dataset involving partially sleep-deprived participants. Fluctuations in functional connectivity thus appear to be clearly associated with changes in arousal. PMID:27512040

  12. Spontaneous eyelid closures link vigilance fluctuation with fMRI dynamic connectivity states.

    PubMed

    Wang, Chenhao; Ong, Ju Lynn; Patanaik, Amiya; Zhou, Juan; Chee, Michael W L

    2016-08-23

    Fluctuations in resting-state functional connectivity occur but their behavioral significance remains unclear, largely because correlating behavioral state with dynamic functional connectivity states (DCS) engages probes that disrupt the very behavioral state we seek to observe. Observing spontaneous eyelid closures following sleep deprivation permits nonintrusive arousal monitoring. During periods of low arousal dominated by eyelid closures, sliding-window correlation analysis uncovered a DCS associated with reduced within-network functional connectivity of default mode and dorsal/ventral attention networks, as well as reduced anticorrelation between these networks. Conversely, during periods when participants' eyelids were wide open, a second DCS was associated with less decoupling between the visual network and higher-order cognitive networks that included dorsal/ventral attention and default mode networks. In subcortical structures, eyelid closures were associated with increased connectivity between the striatum and thalamus with the ventral attention network, and greater anticorrelation with the dorsal attention network. When applied to task-based fMRI data, these two DCS predicted interindividual differences in frequency of behavioral lapsing and intraindividual temporal fluctuations in response speed. These findings with participants who underwent a night of total sleep deprivation were replicated in an independent dataset involving partially sleep-deprived participants. Fluctuations in functional connectivity thus appear to be clearly associated with changes in arousal. PMID:27512040

  13. Efficient mental workload estimation using task-independent EEG features

    NASA Astrophysics Data System (ADS)

    Roy, R. N.; Charbonnier, S.; Campagne, A.; Bonnet, S.

    2016-04-01

    Objective. Mental workload is frequently estimated by EEG-based mental state monitoring systems. Usually, these systems use spectral markers and event-related potentials (ERPs). To our knowledge, no study has directly compared their performance for mental workload assessment, nor evaluated the stability in time of these markers and of the performance of the associated mental workload estimators. This study proposes a comparison of two processing chains, one based on the power in five frequency bands, and one based on ERPs, both including a spatial filtering step (respectively CSP and CCA), an FLDA classification and a 10-fold cross-validation. Approach. To get closer to a real life implementation, spectral markers were extracted from a short window (i.e. towards reactive systems) that did not include any motor activity and the analyzed ERPs were elicited by a task-independent probe that required a reflex-like answer (i.e. close to the ones required by dead man’s vigilance devices). The data were acquired from 20 participants who performed a Sternberg memory task for 90 min (i.e. 2/6 digits to memorize) inside which a simple detection task was inserted. The results were compared both when the testing was performed at the beginning and end of the session. Main results. Both chains performed significantly better than random; however the one based on the spectral markers had a low performance (60%) and was not stable in time. Conversely, the ERP-based chain gave very high results (91%) and was stable in time. Significance. This study demonstrates that an efficient and stable in time workload estimation can be achieved using task-independent spatially filtered ERPs elicited in a minimally intrusive manner.

  14. Data analysis tasks: BATSE

    NASA Technical Reports Server (NTRS)

    Paciesas, William S.

    1993-01-01

    Miscellaneous tasks related to the operation of, and analysis of data from, the Burst and Transient Experiment (BATSE) on the Compton Gamma Ray Observatory (CGRO) were performed. The results are summarized and relevant references are included.

  15. Towards a global system of vigilance and surveillance in unrelated donors of haematopoietic progenitor cells for transplantation.

    PubMed

    Shaw, B E; Chapman, J; Fechter, M; Foeken, L; Greinix, H; Hwang, W; Phillips-Johnson, L; Korhonen, M; Lindberg, B; Navarro, W H; Szer, J

    2013-11-01

    Safety of living donors is critical to the success of blood, tissue and organ transplantation. Structured and robust vigilance and surveillance systems exist as part of some national entities, but historically no global systems are in place to ensure conformity, harmonisation and the recognition of rare adverse events (AEs). The World Health Assembly has recently resolved to require AE/reaction (AE/R) reporting both nationally and globally. The World Marrow Donor Association (WMDA) is an international organisation promoting the safety of unrelated donors and progenitor cell products for use in haematopoietic progenitor cell (HPC) transplantation. To address this issue, we established a system for collecting, collating, analysing, distributing and reacting to serious adverse events and reactions (SAE/R) in unrelated HPC donors. The WMDA successfully instituted this reporting system with 203 SAE/R reported in 2011. The committee generated two rapid reports, reacting to specific SAE/R, resulting in practice changing policies. The system has a robust governance structure, formal feedback to the WMDA membership and transparent information flows to other agencies, specialist physicians and transplant programs and the general public. PMID:23892330

  16. Impact of overnight traffic noise on sleep quality, sleepiness, and vigilant attention in long-haul truck drivers: Results of a pilot study

    PubMed Central

    Popp, Roland FJ; Maier, Stefanie; Rothe, Siegfried; Zulley, Jürgen; Crönlein, Tatjana; Wetter, Thomas C; Rupprecht, Rainer; Hajak, Göran

    2015-01-01

    This study aimed to evaluate the impact of traffic noise along the motorway on sleep quality, sleepiness, and vigilant attention in long-haul truck drivers. This was a randomized, crossover, within-subject controlled study. Healthy long-haul truck drivers spent 6 consecutive nights in a real truck berth with full sleep laboratory equipment. During 3 nights, subjects were exposed to replayed traffic noise alongside motorways, whereas the other 3 nights were without traffic noise. Polysomnography was recorded during the nights and numerous sleepiness tests and vigilance examinations were performed during the following standardized working day. Outcome measures were compared between noisy and silent nights using the paired Wilcoxon test. Ten healthy long-haul truck drivers with a mean age of 36.3 ± 7.3 years completed the study as planned. On noisy nights, subjects had greater latencies to the rapid eye movement (REM) phase (90 ± 32 min vs 69 ± 16 min, P = 0.074) and higher percentages of sleep stage 1 (13.7 ± 5.5% vs 11.2 ± 4.4%; P = 0.059). Subjects also rated their sleep quality as having been better during nights without noise (28.1 ± 3.7 vs 30.3 ± 6.2, P = 0.092). The impact of these differences on daytime sleepiness and vigilance was rather low; however, mean Karolinska Sleepiness Scale (KSS) scores measured during the course of the following day were higher on six out of eight occasions after noisy nights. The effects of overnight traffic noise on sleep quality are detectable but unlikely to have any major impact on the vigilant attention and driving performance of long haul-truck drivers with low nocturnal noise sensitivity. This might not be true for subgroups prone to sleeping disorders. PMID:26572698

  17. Task Switching in a Hierarchical Task Structure: Evidence for the Fragility of the Task Repetition Benefit

    ERIC Educational Resources Information Center

    Lien, Mei-Ching; Ruthruff, Eric

    2004-01-01

    This study examined how task switching is affected by hierarchical task organization. Traditional task-switching studies, which use a constant temporal and spatial distance between each task element (defined as a stimulus requiring a response), promote a flat task structure. Using this approach, Experiment 1 revealed a large switch cost of 238 ms.…

  18. Task-specific Dystonias

    PubMed Central

    Torres-Russotto, Diego; Perlmutter, Joel S.

    2009-01-01

    Task-specific dystonias are primary focal dystonias characterized by excessive muscle contractions producing abnormal postures during selective motor activities that often involve highly skilled, repetitive movements. Historically these peculiar postures were considered psychogenic but have now been classified as forms of dystonia. Writer’s cramp is the most commonly identified task-specific dystonia and has features typical of this group of disorders. Symptoms may begin with lack of dexterity during performance of a specific motor task with increasingly abnormal posturing of the involved body part as motor activity continues. Initially, the dystonia may manifest only during the performance of the inciting task, but as the condition progresses it may also occur during other activities or even at rest. Neurological exam is usually unremarkable except for the dystonia-related abnormalities. Although the precise pathophysiology remains unclear, increasing evidence suggests reduced inhibition at different levels of the sensorimotor system. Symptomatic treatment options include oral medications, botulinum toxin injections, neurosurgical procedures, and adaptive strategies. Prognosis may vary depending upon body part involved and specific type of task affected. Further research may reveal new insights into the etiology, pathophysiology, natural history, and improved treatment of these conditions. PMID:18990127

  19. Task 11 final report

    SciTech Connect

    Bolton, P.

    2000-10-01

    Under this task, RAE personnel were on call to accompany members of the Concerned Citizens for Nuclear Safety (CCNS) if and when they exercised the option to borrow radiac instruments from the Laboratory and survey areas they thought might be contaminated by the Lab. Five members of the RAE team were given refresher training on the latest Lab owned instruments and on Lab procedures for using them and reporting results. On one occasion, a RAE team member accompanied LANL personnel when they did a survey of a house trailer which the owner claimed may have been contaminated. No contamination was found at the site. No requests were received to accompany CCNS members. The original task completion date of September 30, 1998 was extended to June 21, 1999. No requests were received to accompany CCNS members during this timeframe either. The task was terminated as it was determined there was no longer a need.

  20. Assessing L2 Task Performance: Understanding Effects of Task Design

    ERIC Educational Resources Information Center

    Tavakoli, Parvaneh

    2009-01-01

    The overarching aim of the research reported here was to investigate the effects of task structure and storyline complexity of oral narrative tasks on second language task performance. Participants were 60 Iranian language learners of English who performed six narrative tasks of varying degree of structure and storyline complexity in an assessment…

  1. Task Engagement, Cerebral Blood Flow Velocity, and Diagnostic Monitoring for Sustained Attention

    ERIC Educational Resources Information Center

    Matthews, Gerald; Warm, Joel S.; Reinerman-Jones, Lauren E.; Langheim, Lisa K.; Washburn, David A.; Tripp, Lloyd

    2010-01-01

    Loss of vigilance may lead to impaired performance in various applied settings including military operations, transportation, and industrial inspection. Individuals differ considerably in sustained attention, but individual differences in vigilance have proven to be hard to predict. The dependence of vigilance on workload factors is consistent…

  2. Thinking about "Rich" Tasks

    ERIC Educational Resources Information Center

    Box, Lorna; Watson, Anne

    2010-01-01

    This article presents an e-mail conversation between two teachers discussing how to have a "rich task" lesson in which they get to the heart of mathematical modeling and in which students are motivated into working on mathematics. One teacher emphasizes that the power of maths is in developing mathematical descriptions of situations by looking at…

  3. Biomedical applications engineering tasks

    NASA Technical Reports Server (NTRS)

    Laenger, C. J., Sr.

    1976-01-01

    The engineering tasks performed in response to needs articulated by clinicians are described. Initial contacts were made with these clinician-technology requestors by the Southwest Research Institute NASA Biomedical Applications Team. The basic purpose of the program was to effectively transfer aerospace technology into functional hardware to solve real biomedical problems.

  4. Data Center Tasking.

    ERIC Educational Resources Information Center

    Temares, M. Lewis; Lutheran, Joseph A.

    Operations tasking for data center management is discussed. The original and revised organizational structures of the data center at the University of Miami are also described. The organizational strategy addresses the functions that should be performed by the data center, anticipates the specialized skills required, and addresses personnel…

  5. Task 1 quarternary tectonics

    SciTech Connect

    Bell, J.W.

    1994-12-31

    Activities on the task of quarternary tectonics for the Yucca Mountain Site investigations are described. Technical topics include: A preliminary reveiw of Bare Mountain Trench; A preliminary detailed lineament map of the Southwestern part of the proposed repository; A discussion on the 1994 Double Spring Flat, Nevada earthquake; and evidence for temporal clustering.

  6. Project Echo Task Group

    NASA Technical Reports Server (NTRS)

    1964-01-01

    'A technician assigned to the Project Echo Task Group separates the two hemispheres of the Echo 1 container for inspection. The charge that freed the balloon was placed inside of a ring encircling the canister at its equator.' Published in James R. Hansen, Spaceflight Revolution: NASA Langley Research Center From Sputnik to Apollo, NASA SP-4308, p. 181.

  7. Randomization in robot tasks

    NASA Technical Reports Server (NTRS)

    Erdmann, Michael

    1992-01-01

    This paper investigates the role of randomization in the solution of robot manipulation tasks. One example of randomization is shown by the strategy of shaking a bin holding a part in order to orient the part in a desired stable state with some high probability. Randomization can be useful for mobile robot navigation and as a means of guiding the design process.

  8. Mining Task Force Report.

    ERIC Educational Resources Information Center

    Saskatchewan Inst. of Applied Science and Technology, Saskatoon.

    In fall 1988, the Board of Directors of the Saskatchewan Institute of Applied Science and Technology (SIAST) created a task force to study the training needs of the mining industry in the province and evaluate SIAST's responsiveness to those needs. After assessing the technological changes taking place in the industry, surveying manpower needs,…

  9. Chizu Task Mapping Tool

    Energy Science and Technology Software Center (ESTSC)

    2014-07-01

    Chizu is a tool for Mapping MPI processes or tasks to physical processors or nodes for optimizing communication performance. It takes the communication graph of a High Performance Computing (HPC) application and the interconnection topology of a supercomputer as input. It outputs a new MPI rand to processor mapping, which can be used when launching the HPC application.

  10. Creating Positive Task Constraints

    ERIC Educational Resources Information Center

    Mally, Kristi K.

    2006-01-01

    Constraints are characteristics of the individual, the task, or the environment that mold and shape movement choices and performances. Constraints can be positive--encouraging proficient movements or negative--discouraging movement or promoting ineffective movements. Physical educators must analyze, evaluate, and determine the effect various…