Search Results
Results 251 - 300 of 952
< 1 2 3 4 5 6 7 8 9 10 11 >
Wendelken Carter - - 2009
Encoding and dealing with conflicting information is essential for successful decision making in a complex environment. In the present fMRI study, stimulus conflict and response conflict are contrasted in the context of a perceptual decision-making dot-motion discrimination task. Stimulus conflict was manipulated by varying dot-motion coherence along task-relevant and task-irrelevant ...
Wilson Wayne J - - 2011
The aim of this study was to determine if high stimulus repetition rates could reduce the time taken to obtain brainstem auditory evoked response (BAER) waveforms of equivalent quality in dogs. Click-evoked BAER waveforms were obtained from nine healthy, adult, mixed-breed dogs at stimulus intensities of 70, 60, 50 and ...
Koch Stefan P - - 2009
A prompt behavioral response to a stimulus depends both on the salience of the stimulus as well as the subject's preparedness. Thus, both stimulus properties and cognitive factors, such as attention, may determine the strength of neuronal synchronization in the gamma range. For a comprehensive investigation of stimulus-response processing through ...
Weiss Stanley J SJ Psychology Department, American University, Washington, DC 20016, USA. - - 2009
According to the composite-stimulus control model (Weiss, 1969, 1972b), an individual discriminative stimulus (S(D)) is composed of that S(D)'s on-state plus the off-states of all other relevant S(D)s. The present experiment investigated the reversibility of composite-stimulus control. Separate groups of rats were trained to lever-press for food whenever a tone ...
Domenici Paolo P CNR-IAMC Localita Sa Mardini, Torregrande (Or), Italy. - - 2009
The escape response of the cockroach is a well-studied example of sensorimotor behavior. Cockroaches respond to wind puffs, which may signal a predator attack, by making a swift turn followed by a forward acceleration. We have recently shown that their escape trajectories, measured relative to the position of the threatening ...
Chin Sem Sem - - 2009
We used an adaptive optics system to correct the aberration dynamics of five subjects while they fixated on a monochromatic stimulus undergoing sinusoidal vergence changes between 1.5 and 2.5 D, at a temporal frequency of 0.2 Hz. The aberrations were measured at 20 Hz using a Shack-Hartmann sensor and corrected ...
Josić Kresimir - - 2009
The magnitude of correlations between stimulus-driven responses of pairs of neurons can itself be stimulus dependent. We examine how this dependence affects the information carried by neural populations about the stimuli that drive them. Stimulus-dependent changes in correlations can both carry information directly and modulate the information separately carried by ...
Beckmann Joshua S - - 2009
The purpose of the present study was to observe the functional relationship between stimulus dynamics and stimulus duration judgments in humans. Stimulus duration was defined as the length of time that a spinning sphere appeared on a computer screen. Stimulus dynamics were defined by how quickly the sphere rotated on ...
Weihing Jeffrey - - 2009
BACKGROUND: Use of a competition stimuli (e.g., video) in clinical settings is a widespread practice, yet the effects of these stimuli on evoked potentials are not well understood. PURPOSE: The present investigation acquired the click evoked auditory N1-P2 in quiet and in two types of competition: during presentation of an ...
Vallesi Antonino - - 2009
Evidence on the processes underlying the horizontal and vertical Simon effect is still controversial. The present study uses experimental manipulations to selectively delay the stages of response execution, response selection, and stimulus identification in three experiments. A reduction is observed for both horizontal and vertical Simon effects when response execution ...
Hemmi Jan M - - 2009
Habituation is one of the most fundamental learning processes that allow animals to adapt to dynamic environments. It is ubiquitous and often thought of as a simple form of non-associative learning. Very little is known, though, about the rules that govern habituation and their significance under natural conditions. Questions about ...
Ebneter Andreas - - 2010
OBJECTIVE: To investigate the influence of the stimulus parameters on perimetry at various distances and draw conclusions for the clinical exploration of nonorganic visual loss. METHODS: Visual field testing using Goldmann kinetic perimetry was performed on 15 healthy volunteers. The I/1e isopter at 33 cm was compared to the I/1e, ...
Oliver Jon L - - 2009
PURPOSE: The purpose of the current study was to assess the reliability of a new protocol that examines different components of agility using commercially available timing gates. METHODS: Seventeen physically active males completed four trials of a new protocol, which consisted of a number of 10-m sprints. Sprints were completed ...
Yost William A - - 2009
Iterated rippled noise (IRN) was used to study discrimination of IRN stimuli with a lower number of iterations from IRN stimuli with a higher number of iterations as a function of stimulus duration (100-2000 ms). Such IRN stimuli differ in the strength of the repetition pitch. In some cases, the ...
Maddess Ted - - 2009
PURPOSE: This preliminary study investigated a means of concurrently assessing the visual field defects of both eyes by recording pupillary responses to multifocal stimuli. METHODS: Twenty normal subjects and 26 primary open angle glaucoma patients, age and sex matched, were examined by slit-lamp, Humphrey Field Analyser II achromatic 24-2 perimetry ...
Debert Paula - - 2009
Past research has demonstrated emergent conditional relations using a go/no-go procedure with pairs of figures displayed side-by-side on a computer screen. The present study sought to extend applications of this procedure. In Experiment 1, we evaluated whether emergent conditional relations could be demonstrated when two-component stimuli were displayed in figure-ground ...
Bluemke Matthias - - 2009
We investigated the influence of stimulus base rates on the Implicit Association Test (IAT). Using an East/West-German attitude-IAT, we demonstrated that both overall response speed and differential response speed underlying IAT effects depend on the relative frequencies of the stimulus categories. First, when those stimuli that are more common in ...
van Eijk Rob L J - - 2009
Audio-visual stimulus pairs presented at various relative delays, are commonly judged as being "synchronous" over a range of delays from about -50 ms (audio leading) to +150 ms (video leading). The center of this range is an estimate of the point of subjective simultaneity (PSS). The judgment boundaries, where "synchronous" ...
Hulme Oliver J OJ Wellcome Trust Center for Neuroimaging,University College London. - - 2009
Most experiments on the "neural correlates of consciousness" employ stimulus reportability as an operational definition of what is consciously perceived. The interpretation of such experiments therefore depends critically on understanding the neural basis of stimulus reportability. Using a high volume of fMRI data, we investigated the neural correlates of stimulus ...
Kershaw Jeff - - 2009
A new interpretation is proposed for stimulus-induced signal changes in diffusion-weighted functional MRI. T(2)-weighted spin-echo echo-planar images were acquired at different diffusion-weightings while visual stimulation was presented to human volunteers. The amplitudes of the positive stimulus-correlated response and post-stimulus undershoot (PSU) in the functional time-courses were found to follow different ...
Lenassi E - - 2009
AIMS: To investigate the importance of a larger stimulus field for pattern electroretinography (PERG) in evaluating macular function in Stargardt disease, and to determine the relationship between PERG and spectral-domain optical coherence tomography (SD-OCT). METHODS: In this prospective cross-sectional study, PERG from standard (12 degrees x 16 degrees ) and ...
Boenke Lars T LT Leibniz Institute for Neurobiology, 39118 Magdeburg, - - 2009
The temporal integration of stimuli in different sensory modalities plays a crucial role in multisensory processing. Previous studies using temporal-order judgments to determine the point of subjective simultaneity (PSS) with multisensory stimulation yielded conflicting results on modality-specific delays. While it is known that the relative stimulus intensities of stimuli from ...
Bullock Christopher E - - 2009
Acquisition and maintenance of touch-screen responding was examined in naïve cynomolgus monkeys (Macaca fascicularis) under automaintenance and classical conditioning arrangements. In the first condition of Experiment 1, we compared acquisition of screen touching to a randomly positioned stimulus (a gray square) that was either stationary or moving under automaintenance (i.e., ...
Haase Lori L San Diego State University, San Diego, California, - - 2009
Classic psychophysical studies have provided significant information on the psychophysical functions for taste stimuli. With the advent of fMRI, studies are being conducted that provide insight into central processing of gustation in humans. However, fMRI experiments impose physical limitations on stimulus delivery. In the present study, we compared psychophysical functions ...
Kim Jae-Ryong - - 2009
The purpose of this study was to determine whether the electrically evoked acoustic change complex (EACC) could be used to assess sensitivity to changes in stimulus level in cochlear implant (CI) recipients and to investigate the relationship between EACC amplitude and rate of growth of the N1-P2 onset response with ...
Buetti Simona - - 2009
In the Simon effect, participants make a left or right keypress in response to a nonspatial attribute (e.g., color) that is presented on the left or right. Reaction times (RTs) increase when the response activated by the irrelevant stimulus location and the response retrieved by instruction are in conflict. The ...
Stewart Neil - - 2009
For evenly spaced stimuli, a purely relative judgment account of unidimensional categorization performance is trivial: All that is required is knowledge of the size of stimulus difference corresponding to the width of a category. For unevenly spaced stimuli, long-term knowledge of the category structure is required. In the present article, ...
Trojan Jörg - - 2009
The perceptual phenomena of sensory saltation involve the systematic displacement of a target stimulus (the attractee) towards a subsequent stimulus (the attractant), which occurs closely in time and space. Here, we demonstrate the existence of cross-modal tactile-auditory saltation. Tactile stimuli were delivered to the forehead and spatially congruent stereoscopic auditory ...
Rossi Heather L HL College of Dentistry Department of Orthodontics, University of Florida, Gainesville, FL, United - - 2009
Traditional evaluation of pain in animals has primarily used reflexive withdrawal or nocifensive response from singly presented stimulation. However, daily experience of thermal sensation involves situations in which rapid temperature changes from cold to hot can occur. Therefore, in order to better understand integration of competing stimuli and their role ...
Chin Sem Sem - - 2009
BACKGROUND: Accommodation control is mediated by a number of cues, including blur,chromatic aberration and target proximity. Data from wavefront measurements have shown clear shifts in ocular aberrations during increasing accommodative demand, most notably a negative shift in spherical aberration. Work in adaptive optics, where aberrations have been corrected, has suggested ...
Jones Christopher R CR Department of Psychology, Ohio State University, Columbus, OH 43210-1287, - - 2009
Evaluative conditioning (EC) refers to the formation or change of an attitude toward an object, following that object's pairing with positively or negatively valenced stimuli. The authors provide evidence that EC can occur through an implicit misattribution mechanism in which an evaluative response evoked by a valenced stimulus is incorrectly ...
Morewedge Carey K - - 2009
When people are asked to assess or compare the value of experienced or hypothetical events, one of the most intriguing observations is their apparent insensitivity to event duration. The authors propose that duration insensitivity occurs when stimuli are evaluated in isolation because they typically lack comparison information. People should be ...
Lazareva Olga F - - 2009
We (Lazareva, Freiburger, & Wasserman, 2004) previously trained four pigeons to classify color photographs into their basic-level categories (cars, chairs, flowers, or people) or into their superordinate-level categories (natural or artificial). Here, we found that brief stimulus durations had the most detrimental effect on the basic-level discrimination of natural stimuli ...
Ju Xiao-Jie - - 2009
BACKGROUND: Biodegradable stimuli-responsive materials, which exhibit large and sharp physical-chemical changes in response to small physical or chemical stimuli, are attracting increasing interests because of their potential applications in biomedical fields, such as transient implants, drug delivery carriers, and tissue engineering scaffolds. Our previous review (see page 493 of issue ...
Petrini Karin K Department of Psychology, University of Glasgow, Glasgow, G12 8QB Scotland, UK. - - 2009
We investigated the effect of musical expertise on sensitivity to asynchrony for drumming point-light displays, which varied in their physical characteristics (Experiment 1) or in their degree of audiovisual congruency (Experiment 2). In Experiment 1, 21 repetitions of three tempos x three accents x nine audiovisual delays were presented to ...
Komatsu Harunobu - - 2009
Logic-gate operations displaying macroscopic outputs are promising systems for the development of intelligent soft materials that can perform effective functions in response to various input patterns. A supramolecular hydrogel comprising the phosphate-type hydrogelator 1 exhibits macroscopic gel-sol behavior in response to four distinct input stimuli: temperature, pH, Ca(2+), and light. ...
Brantberg Krister - - 2009
OBJECTIVE: To explore the mechanisms for skull tap induced vestibular evoked myogenic potentials (VEMP). METHODS: The muscular responses were recorded over both sternocleidomastoid (SCM) muscles using skin electrodes. A skull tapper which provided a constant stimulus intensity was used to test cervical vestibular evoked myogenic potentials (VEMP) in response to ...
McGreevy Paul D - - 2009
Trained responses are said to be under stimulus control when they appear reliably and exclusively on cue. The SMART system is a conceptual, three-dimensional graphic that uses four quadrants to chart a horse's responsiveness to various cues from two reins and the trainer's legs and seat. The current plots have ...
Boström Kim Joris - - 2009
We investigate the impact of monitor frame rate on the human ocular following response (OFR) and find that the response latency considerably depends on the frame rate in the range of 80-160 Hz, which is far above the flicker fusion limit. From the lowest to the highest frame rate the ...
Ju Xiao-Jie - - 2009
BACKGROUND: Stimuli-responsive materials that undergo dramatic changes in physical-chemical properties in response to mild physical changes in environmental conditions are attracting increasing interest because of their potential application in biomedical fields. Biodegradable materials are highly desired for most biomedical applications in vivo, such as transient implants, drug-delivery carriers, and tissue ...
Kim J-W - - 2009
Under natural conditions, both young-of-the-year (YOY; 0+ year) and parr (1+ year) Atlantic salmon Salmo salar exhibited strong antipredator behaviour (e.g. increase in latency to resume foraging) following the exposure to damage-released chemical alarm cues relative to a stream water control. Subsequent exposure to a novel visual stimulus had contrasting ...
Klosterhalfen Sibylle - - 2009
OBJECTIVE: To investigate the role of Pavlovian conditioning and expectancy and of gender on the nocebo effects. METHODS: Conditioning experiment: Forty-eight healthy male and female volunteers were investigated for 3 days using a standard rotation procedure. Subjects in the experimental group received a salient oral stimulus prior to rotation; subjects ...
Gao Dashan - - 2009
A decision-theoretic formulation of visual saliency, first proposed for top-down processing (object recognition) (Gao & Vasconcelos, 2005a), is extended to the problem of bottom-up saliency. Under this formulation, optimality is defined in the minimum probability of error sense, under a constraint of computational parsimony. The saliency of the visual features ...
Guilhardi Paulo - - 2009
The empirical goals were to describe the behavior of rats trained on multiple temporal discriminations and to use these descriptions to predict behavior observed under new training conditions. The theoretical goals were to fit a quantitative theory to behavior from one training condition, estimate parameters for the intervening perception, memory, ...
de Kort Selvino R - - 2009
Using the responses of territory owners to playback to infer the territorial function of acoustic signals is common practice. However, difficulties with interpreting the results of such experiments have obscured our understanding of territorial signaling. For instance, a stronger response to playback is often interpreted as more aggressive, but there ...
Churan Jan - - 2009
Recent psychophysical work has shown that performance on a direction discrimination task decreases with increasing stimulus size, provided the stimulus is high in contrast. This psychophysical surround suppression has been linked to the inhibitory spatial surrounds that have been observed throughout the primate visual system. In this work we have ...
Daly Edward J EJ - - 2009
The current study examined the accuracy of the multiple-stimulus without replacement (MSWO) preference assessment for identifying preferred common classroom activities as reinforcers with children with behavioral disorders. The accuracy of predictions from the MSWO regarding high, medium, and low stimulus preference was tested by providing contingent access to activities for ...
Liau Joy J Center for Functional Magnetic Resonance Imaging, University of California San Diego, La Jolla, CA 92093-0677, - - 2009
In the application of hypercapnic normalization to functional magnetic resonance imaging (fMRI) studies, the blood oxygenation level dependent (BOLD) response to a functional stimulus is typically divided by the BOLD response to a hypercapnic challenge. While some prior studies have shown that hypercapnic normalization can reduce inter-subject BOLD variability, other ...
Vietze Ina - - 2009
Interference in the Eriksen flanker task has been shown to be reduced when the (relative) frequency of conflicting stimuli is increased, a modulation thought to reflect a higher degree of processing selectivity under conditions of frequent conflict (Botvinick, Braver, Barch, Carter, & Cohen, 2001). Previous studies suggest that stimulus location ...
Seifried Tanja - - 2010
Tse et al. (Percept Psychophys 66:1171-1189, 2004) reported that participants tend to overestimate the duration of an oddball stimulus. The size of this effect was much larger than the one reported by Ulrich et al. (Psychol Res 70:77-87, 2006). More crucially, the effect in the study of Tse et al. ...
< 1 2 3 4 5 6 7 8 9 10 11 >