scholarly journals Perisaccadic flash mislocalization depends on whether a background stimulus appears or disappears around the time of the flash

2011 ◽  
Vol 11 (11) ◽  
pp. 525-525
Author(s):  
J. Pola
Keyword(s):  
Background Stimulus

Delay of Shock-Escape with and without Stimulus Change

1971 ◽  
Vol 29 (1) ◽  
pp. 315-318
Author(s):  
Jesse B. Milby
Keyword(s):  
Negative Reinforcement ◽  
Stimulus Change ◽  
Secondary Reinforcement ◽  
Response Rates ◽  
Shock Termination ◽  
Control Procedure ◽  
Escape Conditioning ◽  
Background Stimulus ◽  
Shock Escape ◽  
Secondary Reinforcing

Effects of a stimulus change presented with delay of shock-escape were examined in escape conditioning. Where a stimulus change occurred with the delay, greater response rates were found before delay and lower rates during the delay. Results are interpreted as providing evidence for the efficacy of a stimulus change in maintaining behavior with delay of negative reinforcement. Results are consistent with an information account of secondary reinforcement. Data from a control procedure suggest the possibility that stimuli paired with shock termination might have two opposite properties, secondary reinforcing and conditioced aversive, depending upon the background stimulus conditions prevailing at testing.

scholarly journals Integration of motion energy from overlapping random background noise increases perceived speed of coherently moving stimuli

2016 ◽  
Vol 116 (6) ◽  
pp. 2765-2776 ◽  
Author(s):  
Jason Chuang ◽  
Emily C. Ausloos ◽  
Courtney A. Schwebach ◽  
Xin Huang
Keyword(s):  
Noise Level ◽  
Background Noise ◽  
Visual Motion ◽  
Random Motion ◽  
Spatial Integration ◽  
Neural Basis ◽  
Motion Energy ◽  
Background Stimulus ◽  
Speed Perception ◽  
Perceived Speed

The perception of visual motion can be profoundly influenced by visual context. To gain insight into how the visual system represents motion speed, we investigated how a background stimulus that did not move in a net direction influenced the perceived speed of a center stimulus. Visual stimuli were two overlapping random-dot patterns. The center stimulus moved coherently in a fixed direction, whereas the background stimulus moved randomly. We found that human subjects perceived the speed of the center stimulus to be significantly faster than its veridical speed when the background contained motion noise. Interestingly, the perceived speed was tuned to the noise level of the background. When the speed of the center stimulus was low, the highest perceived speed was reached when the background had a low level of motion noise. As the center speed increased, the peak perceived speed was reached at a progressively higher background noise level. The effect of speed overestimation required the center stimulus to overlap with the background. Increasing the background size within a certain range enhanced the effect, suggesting spatial integration. The speed overestimation was significantly reduced or abolished when the center stimulus and the background stimulus had different colors, or when they were placed at different depths. When the center- and background-stimuli were perceptually separable, speed overestimation was correlated with perceptual similarity between the center- and background-stimuli. These results suggest that integration of motion energy from random motion noise has a significant impact on speed perception. Our findings put new constraints on models regarding the neural basis of speed perception.

scholarly journals Odor-background segregation of unknown odorants based on stimulus onset asynchrony in honey bees

2019 ◽  
Author(s):  
Aarti Sehdev ◽  
Paul Szyszka
Keyword(s):  
Stimulus Onset Asynchrony ◽  
Honey Bees ◽  
Stimulus Onset ◽  
Sensory Adaptation ◽  
Behavioral Experiments ◽  
Olfactory Information ◽  
Background Stimulus ◽  
Olfactory Organs ◽  
Onset Asynchrony ◽  
Different Sources

ABSTRACTAnimals use olfaction to search for distant objects. Unlike vision, where objects are spaced out, olfactory information mixes when it reaches olfactory organs. Therefore, efficient olfactory search requires segregating odors that are mixed with background odors. Animals can segregate known target odors by detecting short differences in the arrival of odorants from different sources (stimulus onset asynchrony). However, it is unclear whether animals can also use stimulus onset asynchrony to segregate previously unknown odorants that have no innate or learned relevance. Using behavioral experiments in honey bees, we here show that stimulus onset asynchrony also improves odor-background segregation of unknown odorants. The stimulus onset asynchrony necessary to behaviorally segregate unknown odorants is in the range of seconds, which is two orders of magnitude larger than the previously reported stimulus asynchrony sufficient for segregating known odorants. We propose that for unknown odorants, odor-background segregation requires sensory adaptation to the background stimulus.

scholarly journals The Influence of Stimulus Deviance on Electrophysiologic and Behavioral Responses to Novel Events

2000 ◽  
Vol 12 (3) ◽  
pp. 393-406 ◽  
Author(s):  
Kirk R. Daffner ◽  
Leonard F.M. Scinto ◽  
Vivian Calvo ◽  
Robert Faust ◽  
M. Marsel Mesulam ◽  
...  
Keyword(s):  
Cognitive Processing ◽  
Behavioral Responses ◽  
Event Related Potential ◽  
Button Press ◽  
Experimental Conditions ◽  
Background Stimulus ◽  
Preceding Context ◽  
Within Subjects

This study investigated the role of stimulus deviance in determining electrophysiologic and behavioral responses to “novelty.” Stimulus deviance was defined in terms of differences either from the immediately preceding context or from long-term experience. Subjects participated in a visual event-related potential (ERP) experiment, in which they controlled the duration of stimulus viewing with a button press, which served as a measure of exploratory behavior. Each of the three experimental conditions included a frequent repetitive background stimulus and infrequent stimuli that deviated from the background stimulus. In one condition, both background and deviant stimuli were simple, easily recognizable geometric figures. In another condition, both background and deviant stimuli were unusual/unfamiliar figures, and in a third condition, the background stimulus was a highly unusual figure, and the deviant stimuli were simple, geometric shapes. Deviant stimuli elicited larger N2-P3 amplitudes and longer viewing durations than the repetitive background stimulus, even when the deviant stimuli were simple, familiar shapes and the background stimulus was a highly unusual figure. Compared to simple, familiar deviant stimuli, unusual deviant stimuli elicited larger N2-P3 amplitudes and longer viewing times. Within subjects, the deviant stimuli that evoked the largest N2-P3 responses also elicited the longest viewing durations. We conclude that deviance from both immediate context and long-term prior experience contribute to the response to novelty, with the combination generating the largest N2-P3 amplitude and the most sustained attention. The amplitude of the N2-P3 may reflect how much “uncertainty” is evoked by a novel visual stimulus and signal the need for further exploration and cognitive processing.

Effects of Background Stimulation upon Eye-Movement Information

1996 ◽  
Vol 82 (2) ◽  
pp. 627-635 ◽  
Author(s):  
Shinji Nakamura
Keyword(s):  
Eye Movement ◽  
Optic Flow ◽  
Object Motion ◽  
Image Motion ◽  
High Contrast ◽  
Striped Pattern ◽  
Background Stimulus ◽  
Background Stimulation ◽  
Spatial Frequencies ◽  
Retinal Image Motion

To investigate the effects of background stimulation upon eye-movement information (EMI), the perceived deceleration of the target motion during pursuit eye movement (Aubert-Fleishl paradox) was analyzed. In the experiment, a striped pattern was used as a background stimulus with various brightness contrasts and spatial frequencies for serially manipulating the attributions of the background stimulus. Analysis showed that the retinal-image motion of the background stimulus (optic flow) affected eye-movement information and that the effects of optic flow became stronger when high contrast and low spatial frequency stripes were presented as the background stimulus. In conclusion, optic flow is one source of eye-movement information in determining real object motion, and the effectiveness of optic flow depends on the attributes of the background stimulus.

The Influence of Eccentricity, Contrast, and Angular Extent on the Perception of Peripheral Apparent Motion

1989 ◽  
Vol 33 (20) ◽  
pp. 1445-1449 ◽  
Author(s):  
Woodrow Barfield ◽  
Loo Kar Bun ◽  
Conrad Kraft
Keyword(s):  
Apparent Motion ◽  
Angular Separation ◽  
Ambient Illumination ◽  
Athletic Ability ◽  
Background Stimulus ◽  
Angular Extent ◽  
Stimulus Target ◽  
Main Effects

Two experiments were performed to investigate the perception of peripherally presented apparent motion as a function of eccentricity of the stimulus, ambient illumination, gender, athletic ability, age, stimuli pattern (diamond, square), and angular extent of stimuli presentation. The experiment task for both studies was to determine the direction of apparent motion for a lighter than background stimulus target presented on a Braumbach perimeter. The results from experiment one indicated main effects for subjects, eccentricity, and age. The results from experiment two indicated main effects for subjects, eccentricity, and angular separation of the apparent motion.

Effects of Background Motion on Eye-Movement Information

1997 ◽  
Vol 84 (1) ◽  
pp. 107-113
Author(s):  
Shinji Nakamura
Keyword(s):  
Spatial Frequency ◽  
Eye Movement ◽  
Optic Flow ◽  
Retinal Image ◽  
Target Velocity ◽  
Striped Pattern ◽  
Background Stimulus ◽  
Spatial Frequencies ◽  
Background Motion ◽  
Perceived Velocity

The effect of background stimulus on eye-movement information was investigated by analyzing the underestimation of the target velocity during pursuit eye movement (Aubert-Fleishl paradox). In the experiment, a striped pattern with various brightness contrasts and spatial frequencies was used as a background stimulus, which was moved at various velocities. Analysis showed that the perceived velocity of the pursuit target, which indicated the magnitudes of eye-movement information, decreased when the background stripes moved in the same direction as eye movement at higher velocities and increased when the background moved in the opposite direction. The results suggest that the eye-movement information varied as a linear function of the velocity of the motion of the background retinal image (optic flow). In addition, the effectiveness of optic flow on eye-movement information was determined by the attributes of the background stimulus such as the brightness contrast or the spatial frequency of the striped pattern.

Threshold fluctuations on temporally modulated backgrounds: A possible physiological explanation based upon a recent computational model

1998 ◽  
Vol 15 (5) ◽  
pp. 957-967 ◽  
Author(s):  
D.C. HOOD ◽  
N. GRAHAM
Keyword(s):  
Light Adaptation ◽  
Threshold Elevation ◽  
Sinusoidal Modulation ◽  
Simple Observation ◽  
Background Stimulus ◽  
Number Of Factors ◽  
Physiological Explanation ◽  
On And Off Pathways ◽  
Threshold Variation ◽  
Key Aspects

When a temporally fluctuating background is rapidly modulated (e.g. 30 Hz), the threshold variation of a superimposed flash (the probe) is approximately sinusoidal and in phase with the stimulus. But, with low rates of sinusoidal modulation (e.g. 1 Hz), the threshold variation is distinctly nonsinusoidal in shape. The bases of these aspects of the data, as well as an unmodulated, dc, threshold elevation, are poorly understood. Here 30-Hz and 1-Hz conditions are simulated using a new model of light adaptation (Wilson, 1997). By assuming that the OFF pathway is twice as sensitive as the ON pathway, the model correctly captured the key aspects of both conditions. The results suggest that the 1-Hz data are mediated by a mixture of ON and OFF pathways while the 30-Hz data are largely mediated by the OFF pathway. The probe thresholds on the 30-Hz background appear approximately sinusoidal and approximately in phase with the background stimulus. A number of factors contribute to this deceptively simple observation.

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