Search Results
Results 301 - 350 of 952
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Gurnsey Rick - - 2008
There is conflicting evidence about whether stimulus magnification is sufficient to equate the discriminability of point-light walkers across the visual field. We measured the accuracy with which observers could report the directions of point-light walkers moving +/-4 degrees from the line of sight, and the accuracy with which they could ...
Hammer Michael J MJ Department of Surgery, University of Wisconsin, Madison, WI 53792, USA. - - 2009
Laryngeal control is essential for airway protection, breathing, deglutition, speech, and voice. Unfortunately, integration of laryngeal sensory assessment in research and clinical practice is limited by technical and practical limitations of commercially available technology. A commercial device is available, but reported limitations include procedural complexity requiring two or three individuals ...
Hirai Masahiro - - 2008
OBJECTIVE: The aim of this study is to extract magnetoencephalographic responses relating to the processing of point-light walker (PLW). METHODS: To attenuate neural activities in the lower visual areas, we presented a scrambled-PLW as a first stimulus and then either an upright- or inverted-PLW/scrambled-PLW as a second stimulus. Each point ...
Millslagle Duane G - - 2008
The effects of intratrial stimulus speeds on coincidence-anticipation timing was investigated. The Bassin Anticipation Timer was used to test 82 participants' response times when the intratrial stimulus speed decreased, was constant, or increased. Analysis showed a significant temporal directional bias with increased and decreased intratrial speed. Decreasing intratrial stimulus speed ...
Chatterjee Anushree A Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, MN 55455-0132, - - 2008
Many biological events are binary. The switch between mutually exclusive OFF to ON state in response to a stimulus is frequently mediated by a control circuit with a positive and/or a negative feedback. Such a system typically exhibits hysteresis with its switching ON and OFF stimulus levels dependent on the ...
Prinzmetal William - - 2008
Carrasco, Ling, and Read (2004) reported that involuntary attention increased perceived contrast. We replicated Carrasco et al. and then tested an alternative hypothesis: With stimuli near threshold, a peripheral cue biased observers to believe a stimulus had been presented in the cued location. Consistent with this hypothesis, the effect disappeared ...
Wilkinson Anna - - 2009
Although the pigeon is a popular model for studying visual perception, relatively little is known about its perception of motion. Three experiments examined the pigeons' ability to capture a moving stimulus. In Experiment 1, the effect of manipulating stimulus speed and the length of the stimulus was examined using a ...
Barry Robert J - - 2009
The orienting reflex (OR), elicited by an innocuous stimulus, can be regarded as a model of the organism's interaction with its environment, and has been described as the unit of attentional processing. A major determinant of the OR is the novelty of the eliciting stimulus, generally operationalized in terms of ...
van Erp Jan B F - - 2008
Vibrotactile mobility systems present spatial information such as the direction of a waypoint through a localized vibration on the torso. Using these systems requires the ability to determine the absolute location of the stimulus. Because data are available only on the ability to determine the relative location of stimuli on ...
Kida Ikuhiro - - 2008
Understanding the mechanism of coupling between neuronal events and hemodynamic responses is important in non-invasive functional imaging of the brain. The stimulus frequency dependence of hemodynamic responses has been studied using a rat somatosensory cortex model; most results for short stimulus durations reveal peak frequencies at which the hemodynamic response ...
Kang Min-Suk - - 2008
Rapid, repetitive exchange of dissimilar, rival stimuli between the two eyes can produce slow alternations in perceptual dominance. This phenomenon, called stimulus rivalry, is potentially important for studying resolution of visual conflict associated with neural processing beyond the level of interocular competition. As previously implemented, however, stimulus rivalry can be ...
Witnauer James E JE State University of New York, Binghamton, New York 13902-6000, - - 2008
Weak behavioral control (blocking) occurs when a target stimulus (X) is paired with an outcome in the presence of a well-established signal for the outcome (i.e., a blocking stimulus). Conventional Pavlovian conditioning theories explain this effect by asserting that a discrepancy between expected and experienced outcomes is necessary for learning ...
Wedell Douglas H - - 2008
This research examines whether an extension of range-frequency theory (Parducci, 1965) could successfully predict context effects on discrimination between stimuli for two-category rating data. The new model proposes that similarity comparisons between stimulus values and rating category prototypes take place on an implicit range-frequency scale, and thus it entails effects ...
Carbone Elena - - 2008
According to the Fröhlich effect, observers perceive the initial position of a fast moving stimulus displaced in the direction of motion. On the basis of Kirschfeld and Kammer's as well as Fröhlich's original assumption that metacontrast plays an important role in the emergence of the phenomenon, we predicted different amounts ...
Fründ Ingo - - 2008
In everyday life we often encounter situations in which we can expect a visual stimulus before we actually see it. Here, we study the impact of such stimulus anticipation on the actual response to a visual stimulus. Participants were to indicate the sex of deer and cattle on photographs of ...
Yap Melvin J MJ Department of Psychology, Washington University St Louis, St Louis, MO 63130, - - 2008
The joint effects of stimulus quality and word frequency in lexical decision were examined in 4 experiments as a function of nonword type (legal nonwords, e.g., BRONE, vs. pseudohomophones, e.g., BRANE). When familiarity was a viable dimension for word-nonword discrimination, as when legal nonwords were used, additive effects of stimulus ...
Wühr Peter - - 2008
Six experiments investigated how variability on irrelevant stimulus dimensions and variability on response dimensions contribute to spatial and nonspatial stimulus-response (S-R) correspondence effects. Experiments 1-3 showed that, when stimuli varied in location and number, S-R correspondence effects for location or numerosity occurred when responses varied on these dimensions but not ...
Fischer Rico - - 2008
In a visual simple reaction time paradigm with attention divided between the left and right visual fields, redundancy gain refers to the finding of faster responses to stimuli presented in both fields than to single stimuli. The present study investigated whether the effects of low-level perceptual processing affect the redundancy ...
Los Sander A - - 2008
In reaction time (RT) research on nonspecific preparation, the preparation period is often identified with the foreperiod (FP), the interval between the offset of a neutral warning stimulus (S1) and the onset of the reaction stimulus (S2). However, the "effective preparation period" may be longer than FP: nonspecific preparation may ...
Krogh-Madsen Trine - - 2008
Ventricular tachycardia is a type of cardiac arrhythmia that can be associated with a wave circulating around in a loop. Because this rhythm is potentially fatal, its termination is highly desirable. Theoretical approaches have suggested that discontinuity in the phase resetting response to electrical stimuli is indicative of the ability ...
Tozawa Junko - - 2008
The distance-calibration hypothesis states that retinal velocity is scaled by using distance cues, and judged velocity remains unchanged when distance is changed. The relational hypothesis states that judged velocity depends on retinal velocities, and is proportional to judged distance. These hypotheses were compared in three experiments where the movements of ...
Zhang Zheng - - 2008
BACKGROUND: The traditional two-point discrimination (TPD) test, a widely used tactile spatial acuity measure, has been criticized as being imprecise because it is based on subjective criteria and involves a number of non-spatial cues. The results of a recent study showed that as two stimuli were delivered simultaneously, vibrotactile amplitude ...
Mo Lingyan - - 2008
OBJECTIVE: To investigate the effect of brief-tone stimulus duration on the amplitude of the brain stem auditory steady-state response (ASSR), both in single- and multiple-stimulus conditions. DESIGN: In Experiment 1, the primary stimuli were Blackman-windowed 500- and 2000-Hz brief tones presented using repetition rates of 79 and 83 Hz, respectively. ...
Wright Geraldine A - - 2008
Animals use odors as signals for mate, kin, and food recognition, a strategy which appears ubiquitous and successful despite the high intrinsic variability of naturally-occurring odor quantities. Stimulus generalization, or the ability to decide that two objects, though readily distinguishable, are similar enough to afford the same consequence, could help ...
Hernández Oscar H - - 2008
Omitted stimulus potentials (OSP) are waves that are considered to involve moderately high-level processing, but their relation to the cognitive, premotor component of reaction time (PMRT) to an omitted stimulus has not been examined. This relationship was tested in 20 participants who responded to an auditory omitted stimulus occurring in ...
Lesica Nicholas A - - 2008
The reasons for using natural stimuli to study sensory function are quickly mounting, as recent studies have revealed important differences in neural responses to natural and artificial stimuli. However, natural stimuli typically contain strong correlations and are spherically asymmetric (i.e. stimulus intensities are not symmetrically distributed around the mean), and ...
Vicario Carmelo Mario - - 2008
Time, space and numbers are closely linked in the physical world. However, the relativistic-like effects on time perception of spatial and magnitude factors remain poorly investigated. Here we wanted to investigate whether duration judgments of digit visual stimuli are biased depending on the side of space where the stimuli are ...
Lightfoot Guy - - 2007
PURPOSE: To make the audiologic community aware of a technical issue with potential for misunderstanding that could affect the design, calibration, and use of auditory brainstem response (ABR) systems. METHOD: Two international standards published in 2007 relating to the stimuli commonly used in ABR tests were studied and the behavior ...
Savazzi Silvia S Department of Neurological and Vision Science, University of Verona, 8 Strada le Grazie, 37134, Verona, - - 2008
To try and cast light on the processing locus of the redundant signal effect (RSE), i.e. the speeding of reaction time (RT) with two rather than one stimulus, we manipulated three features of redundant visual stimuli, i.e. exposure duration, intensity and interstimulus interval (ISI). We found an inverse relationship between ...
Strudwick Mark W - - 2007
The investigation of proposed acupuncture models is experiencing increasing interest particularly since the inception of functional neuroimaging in the early 1990s, but difficulty in providing acceptable controls has been an ongoing limitation. The use of titrated stimulation to generate a dose response is implied in the nature of the stimulus ...
Fournier Lisa R - - 2007
Across two experiments, decision priming was examined for conjunctions composed of first-order or first- and second-order stimulus features. Observers indicated the presence or absence of one or two features in a Gabor stimulus. When a pair of stimulus features differed in their speed of discrimination, responses indicating the presence of ...
SokoĊ‚owska B - - 2007
The intermittent hypoxia (IH) phenomenon is a subject of intensive examinations. In this study we examined whether it could be possible to distinguish the strength of the hypoxic stimulus given in IH cycles on the basis of observed changes in the breathing pattern. We investigated the ventilatory responses to five ...
Castro-Barros B A - - 2008
Evidence exists that both right and left hemisphere attentional mechanisms are mobilized when attention is directed to the right visual hemifield and only right hemisphere attentional mechanisms are mobilized when attention is directed to the left visual hemifield. This arrangement might lead to a rightward bias of automatic attention. The ...
Machado Liana - - 2007
Humans have a remarkable capability to respond efficiently to a stimulus of interest despite other stimuli competing for neural resources. The current study investigated how the human system copes with distracting stimuli. During each trial, participants viewed 2 sequential stimuli that were each associated with a specific action based on ...
Lentz Jennifer J - - 2007
This study evaluated whether weights for spectral-shape discrimination depend on overall stimulus level and signal strength (the degree of spectral-shape change between two stimuli). Five listeners discriminated between standard stimuli that were the sum of six equal-amplitude tones and signal stimuli created by decreasing the amplitudes of three low-frequency components ...
Bender Stephan - - 2007
The ventrolateral prefrontal cortex (VLPFC) is implicated in contingency detection and the evaluation of emotionally significant stimuli. However, the mechanisms whereby an individual can effectively avoid painful or unpleasant events are not well understood. We therefore examined whether the absence of an unpleasant somatosensory stimulus could evoke a response in ...
Ma Qingguo - - 2007
The aim of this study is to investigate the neural mechanism of extending a brand in a specific product category to other product categories. Facing two sequential stimuli in pairs consisting of beverage brand names (stimulus 1) and product names (stimulus 2) in other categories, 16 participants were asked to ...
León-Carrión Jose - - 2007
This paper introduces a new paradigm in the study of emotional processes through functional neuroimaging. We study whether the valence and arousal of visual stimuli influence neuroimaging of the evoked hemodynamic changes. Using functional near-infrared spectroscopy (fNIRS), we investigate evoked-cerebral blood oxygenation (CBO) changes in dorsolateral prefrontal cortex (DLPFC) during ...
Zellner Debra A - - 2007
The paper addresses the topic of how much an individual likes a stimulus and also how much that individual prefers it to other stimuli. Research is reviewed showing that the context in which the stimulus is presented affects both liking and preference judgments. Having subjects think of the context stimuli ...
Diaz-Santana L - - 2007
We present a methodology to measure the systematic changes of aberrations induced by small changes in amplitude of accommodation. We use a method similar the one used in electrophysiology, where a periodic stimulus is presented to the eye and many periods (epochs) of the stimulus are averaged. Using this technique ...
Moseley G Lorimer - - 2007
The influence of contextual factors on the pain evoked by a noxious stimulus is not well defined. In this study, a -20 degrees C rod was placed on one hand for 500 ms while we manipulated the evaluative context (or 'meaning') of, warning about, and visual attention to, the stimulus. ...
Reinhard Günter - - 2007
Stimuli presented with a low frequency elicit larger pupillary responses than those presented with a high frequency. Similar effects are known for motor responses observed in reaction time experiments. Utilizing this stimulus probability effect, we conducted a Go/NoGo reaction time experiment and measured pupillary dilation to evaluate categorization. We found ...
Aguirre Geoffrey Karl GK Department of Neurology, University of Pennsylvania, 3 West Gates, 3400 Spruce Street, Philadelphia, PA 19104, USA. - - 2007
This paper describes continuous carry-over fMRI experiments. In these studies, stimuli are presented in an unbroken, sequential manner, and can be used to estimate simultaneously the mean difference in neural activity between stimuli as well as the effect of one stimulus upon another (carry-over effects). Neural adaptation, which has been ...
Henson R N RN MRC Cognition and Brain Sciences Unit, 15 Chaucer Road, Cambridge, England, UK. rik.henson@mrc-cbu.cam.ac.uk - - 2007
The aim of this fMRI study was to investigate whether spatial attention to the initial and/or repeated presentation of a stimulus is necessary to observe repetition-related modulations of the neural responses evoked by that stimulus. During each trial, two stimuli were presented simultaneously, one left and one right of fixation. ...
Hadjipapas Avgis - - 2007
Gamma activity to stationary grating stimuli was studied non-invasively using MEG recordings in humans. Using a spatial filtering technique, we localized gamma activity to primary visual cortex. We tested the hypothesis that spatial frequency properties of visual stimuli may be related to the temporal frequency characteristics of the associated cortical ...
Pariyadath Vani V Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of - - 2007
Events can sometimes appear longer or shorter in duration than other events of equal length. For example, in a repeated presentation of auditory or visual stimuli, an unexpected object of equivalent duration appears to last longer. Illusions of duration distortion beg an important question of time representation: when durations dilate ...
Fischer Rico - - 2007
In a recent study, it was shown that subliminal priming (SP) effects are affected by the temporal predictability of a stimulus onset. If predictability is not given, SP effects are eliminated (Naccache, Blandin, & Dehaene, 2002). In two experiments, we investigated how different levels of preparation for target processing affect ...
Carlsen Anthony N AN School of Human Kinetics, University of British Columbia, Vancouver, Canada. - - 2007
Recent experiments pairing a startling stimulus with a simple reaction time (RT) task have shown that when participants are startled, a prepared movement was initiated earlier in comparison to voluntary initiation. It has been argued that the startle acts to trigger the response involuntarily. However, an alternative explanation is that ...
Blanc Jean-Luc - - 2007
To understand how information is coded in the primary somatosensory cortex (S1) we need to decipher the relationship between neural activity and tactile stimuli. Such a relationship can be formally measured by mutual information. The present study was designed to determine how S1 neuronal populations code for the multidimensional kinetic ...
Steinhilber Jody - - 2007
The effects of stimulus availability on preference were evaluated using two conditions of a modified preference assessment. Different preference hierarchies were found in 15-s access conditions than in 15-min access conditions. Subsequent comparisons of a short-availability high-preference stimulus and a long-availability high-preference stimulus verified differential preferences for stimuli based on ...
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