991 resultados para sensory perception


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This study is one of the first studies to approach workplace bullying cross-culturally. It sought to compare employees' understanding of workplace bullying in two different world regions: Central America and Southern Europe, regarding three aspects of workplace bullying: psychological vs. physical harassment, hierarchical vs. horizontal bullying, and direct vs. indirect aggression. A convenience sample of 246 workers provided their own definition of workplace bullying through a single, open-ended question. The results showed that employees from Central America emphasized the physical component of workplace bullying more than the Southern European employees. However, similarities in the conceptualization of workplace bullying across both cultures were found as well. Both Southern European and Central American employees defined workplace bullying mainly as a hierarchical phenomenon, where the aggression took the form of direct strategies. Such differences and similarities bring to the field some positive inputs for the development and implementation of different strategies for dealing effectively with this phenomenon.

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This contract extension was granted to analyze data obtained in the original contract period at a level of detail not called for in the original contract nor permitted by the time constraints of the original contract schedule. These further analyses focused on two primary questions: I. What sources of variation can be isolated within the overall pattern of driver recognition errors reported previously for the 16 signs tested in Project HR-256? 2. Were there systematic relations among data on the placement of signs in a simulated signing exercise and data on the respondents' ability to detect the presence of a sign in a visual field or their ability to recognize quickly and correctly a sign shown them or the speed with which these same persons can respond to a sign for a driver decision?

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Rats, like other crepuscular animals, have excellent auditory capacities and they discriminate well between different sounds [Heffner HE, Heffner RS, Hearing in two cricetid rodents: wood rats (Neotoma floridana) and grasshopper mouse (Onychomys leucogaster). J Comp Psychol 1985;99(3):275-88]. However, most experimental literature concerning spatial orientation almost exclusively emphasizes the use of visual landmarks [Cressant A, Muller RU, Poucet B. Failure of centrally placed objects to control the firing fields of hippocampal place cells. J Neurosci 1997;17(7):2531-42; and Goodridge JP, Taube JS. Preferential use of the landmark navigational system by head direction cells in rats. Behav Neurosci 1995;109(1):49-61]. To address the important issue of whether rats are able to achieve a place navigation task relative to auditory beacons, we designed a place learning task in the water maze. We controlled cue availability by conducting the experiment in total darkness. Three auditory cues did not allow place navigation whereas three visual cues in the same positions did support place navigation. One auditory beacon directly associated with the goal location did not support taxon navigation (a beacon strategy allowing the animal to find the goal just by swimming toward the cue). Replacing the auditory beacons by one single visual beacon did support taxon navigation. A multimodal configuration of two auditory cues and one visual cue allowed correct place navigation. The deletion of the two auditory or of the one visual cue did disrupt the spatial performance. Thus rats can combine information from different sensory modalities to achieve a place navigation task. In particular, auditory cues support place navigation when associated with a visual one.

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This research extends a previously developed work concerning about the use of local model predictive control in mobile robots. Hence, experimental results are presented as a way to improve the methodology by considering aspects as trajectory accuracy and time performance. In this sense, the cost function and the prediction horizon are important aspects to be considered. The platformused is a differential driven robot with a free rotating wheel. The aim of the present work is to test the control method by measuring trajectory tracking accuracy and time performance. Moreover, strategies for the integration with perception system and path planning are also introduced. In this sense, monocular image data provide an occupancy grid where safety trajectories are computed by using goal attraction potential fields

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BACKGROUND AND PURPOSE: APETx2, a toxin from the sea anemone Anthropleura elegantissima, inhibits acid-sensing ion channel 3 (ASIC3)-containing homo- and heterotrimeric channels with IC(50) values < 100 nM and 0.1-2 µM respectively. ASIC3 channels mediate acute acid-induced and inflammatory pain response and APETx2 has been used as a selective pharmacological tool in animal studies. Toxins from sea anemones also modulate voltage-gated Na(+) channel (Na(v) ) function. Here we tested the effects of APETx2 on Na(v) function in sensory neurones.¦EXPERIMENTAL APPROACH: Effects of APETx2 on Na(v) function were studied in rat dorsal root ganglion (DRG) neurones by whole-cell patch clamp.¦KEY RESULTS: APETx2 inhibited the tetrodotoxin (TTX)-resistant Na(v) 1.8 currents of DRG neurones (IC(50) , 2.6 µM). TTX-sensitive currents were less inhibited. The inhibition of Na(v) 1.8 currents was due to a rightward shift in the voltage dependence of activation and a reduction of the maximal macroscopic conductance. The inhibition of Na(v) 1.8 currents by APETx2 was confirmed with cloned channels expressed in Xenopus oocytes. In current-clamp experiments in DRG neurones, the number of action potentials induced by injection of a current ramp was reduced by APETx2.¦CONCLUSIONS AND IMPLICATIONS: APETx2 inhibited Na(v) 1.8 channels, in addition to ASIC3 channels, at concentrations used in in vivo studies. The limited specificity of this toxin should be taken into account when using APETx2 as a pharmacological tool. Its dual action will be an advantage for the use of APETx2 or its derivatives as analgesic drugs.

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The objective of this work was to study the foraging behavior of Telenomus podisi Ashmead (Hymenoptera: Scelionidae) in the presence of stimuli from its host, Euschistus heros (Heteroptera: Pentatomidae). The stimuli selected were: egg mass; virgin males and females; volatile extracts of sexually mature males and females; components of male sex pheromone; a component of the alarm pheromone, hexane and an empty cage as control. In a closed arena, the parasitoids were given the choice between single and combined stimuli presented to them simultaneously. To find the host egg, T. podisi primarily uses the sensory cues released from the male insects. The orientation toward odors of male chemical extract indicates that a source of kairomone was detected. Gas chromatographic analyses of this substance showed peak of methyl 2,6,10-trimethyltridecanoate, the main component of male sexual pheromone. The sensory response to methyl 2,6,10-trimethyltridecanoate confirms that this compound may act as a kairomone to find host eggs. Females and egg mass stimuli were weakly attractive to the parasitoid.

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Sensory information can interact to impact perception and behavior. Foods are appreciated according to their appearance, smell, taste and texture. Athletes and dancers combine visual, auditory, and somatosensory information to coordinate their movements. Under laboratory settings, detection and discrimination are likewise facilitated by multisensory signals. Research over the past several decades has shown that the requisite anatomy exists to support interactions between sensory systems in regions canonically designated as exclusively unisensory in their function and, more recently, that neural response interactions occur within these same regions, including even primary cortices and thalamic nuclei, at early post-stimulus latencies. Here, we review evidence concerning direct links between early, low-level neural response interactions and behavioral measures of multisensory integration.

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Seeing seems effortless, despite the need to segregate and integrate visual information that varies in quality, quantity, and location. The extent to which seeing passively recapitulates the external world is challenged by phenomena such as illusory contours, an example of visual completion whereby borders are perceived despite their physical absence in the image. Instead, visual completion and seeing are increasingly conceived as active processes, dependent on information exchange across neural populations. How this is instantiated in the brain remains controversial. Divergent models emanate from single-unit and population-level electrophysiology, neuroimaging, and neurostimulation studies. We reconcile discrepant findings from different methods and disciplines, and underscore the importance of taking into account spatiotemporal brain dynamics in generating models of brain function and perception.

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It is known that post-movement beta synchronization (PMBS) is involved both in active inhibition and in sensory reafferences processes. The aim of this study was examine the temporal and spatial dynamics of the PMBS involved during multi-limb coordination task. We investigated post-switching beta synchronization (assigned PMBS) using time-frequency and source estimations analyzes. Participants (n = 17) initiated an auditory-paced bimanual tapping. After a 1500 ms preparatory period, an imperative stimulus required to either selectively stop the left while maintaining the right unimanual tapping (Switch condition: SWIT) or to continue the bimanual tapping (Continue condition: CONT). PMBS significantly increased in SWIT compared to CONT with maximal difference within right central region in broad-band 14âeuro"30 Hz and within left central region in restricted-band 22âeuro"26 Hz. Source estimations localized these effects within right pre-frontal cortex and left parietal cortex, respectively. A negative correlation showed that participants with a low percentage of errors in SWIT had a large PMBS amplitude within right parietal and frontal cortices. This study shows for the first time simultaneous PMBS with distinct functions in different brain regions and frequency ranges. The left parietal PMBS restricted to 22âeuro"26 Hz could reflect the sensory reafferences of the right hand tapping disrupted by the switching. In contrast, the right pre-frontal PMBS in a broad-band 14âeuro"30 Hz is likely reflecting the active inhibition of the left hand stopped. Finally, correlations between behavioral performance and the magnitude of the PMBS suggest that beta oscillations can be viewed as a marker of successful active inhibition.