scholarly journals Stimulus strength and dominance duration in perceptual bi-stability. Part I: the unperceived stimulus affects the very first dominance epoch

2010 ◽  
Vol 2 (7) ◽  
pp. 461-461
Author(s):  
N. Rubin ◽  
J.-M. Hupe ◽  
M. Meng ◽  
F. Tong
Keyword(s):  
Stimulus Strength ◽  
Dominance Duration

scholarly journals Extending Levelt’s Propositions to perceptual multistability involving interocular grouping

2016 ◽  
Author(s):  
Alain Jacot-Guillarmod ◽  
Yunjiao Wang ◽  
Claudia Pedroza ◽  
Haluk Ogmen ◽  
Zachary Kilpatrick ◽  
...  
Keyword(s):  
Hierarchical Model ◽  
Color Image ◽  
Stimulus Strength ◽  
Low Level ◽  
Color Saturation ◽  
Modeling Studies ◽  
Visual Hemifield ◽  
Neural Populations ◽  
The Difference ◽  
Dominance Duration

AbstractLevelt’s Propositions have been a touchstone for experimental and modeling studies of perceptual multistability. We asked whether Levelt’s Propositions extend to perceptual multistability involving interocular grouping. To address this question we used split-grating stimuli withcomplementary halves of the same color. As in previous studies, subjects reported four percepts in alternation: the two stimuli presented to each eye (single-eye percepts), as well as two interocularly grouped, single color percepts (grouped percepts). Most subjects responded to increased color saturation by more frequently reporting a single color image, thus increasingthe predominance of grouped percepts (Levelt’s Proposition I). In these subjects increased predominance was due to a decrease in the average dominance duration of single-eye percepts, while that of grouped percepts remained largely unaffected. This is in accordance with generalized Levelt’s Proposition II which posits that the average dominance duration of the stronger (in this case single-eye) percept is primarily affectedbychanges in stimulus strength. In accordance with Proposition III, thealternation rate increased as the difference in the strength of the percepts decreased. To explain the mechanism behind these observations, we introduce a hierarchical model consisting of low-level neural populations, eachresponding to input at a visual hemifield, and higher-level populations representing the percepts. The model exhibits the changes in dominance durationobserved in the data, and conforms to all of Levelt’s Propositions.

scholarly journals Feasibility of adjusting paced left ventricular activation by manipulating stimulus strength

2004 ◽  
Vol 44 (11) ◽  
pp. 2249-2252 ◽  
Author(s):  
Usha Tedrow ◽  
William H. Maisel ◽  
Laurence M. Epstein ◽  
Kyoko Soejima ◽  
William G. Stevenson
Keyword(s):  
Left Ventricular ◽  
Stimulus Strength ◽  
Ventricular Activation

Arousal responses to hypertension in lambs: effect of sinoaortic denervation

1991 ◽  
Vol 260 (4) ◽  
pp. H1283-H1289 ◽  
Author(s):  
R. S. Horne ◽  
N. D. De Preu ◽  
P. J. Berger ◽  
A. M. Walker
Keyword(s):  
Eye Movement ◽  
Rem Sleep ◽  
Threshold Model ◽  
Arterial Oxygen Saturation ◽  
Arterial Oxygen ◽  
Stimulus Strength ◽  
Partial Pressure Of Oxygen ◽  
Quiet Sleep ◽  
Acute Hypertension ◽  
Neural Processes

Newborn lambs were subjected to hypertensive stimuli of 1-min duration to examine features of hypertension-induced arousal from sleep. Reflex mechanisms involved were studied by performing the same tests after sinoaortic denervation (SAD). In intact lambs, hypertension increased the probability of arousal from both quiet sleep (QS) and rapid-eye-movement (REM) sleep. Hypertension resulted in arousal in 51% (QS) and 50% (REM) of tests. Arousal time was significantly longer in REM (29.3 +/- 0.9 s, mean +/- SE) than in QS (22.6 +/- 0.6 s, P less than 0.01). Arterial oxygen saturation (So2) and partial pressure of oxygen (Po2) measured at the point of arousal, or after 60 s if arousal failed to occur, were unchanged from control values. After SAD hypertension did not increase the probability of arousal. Arousals significantly decreased (P less than 0.001) to 31% (QS) and 10% (REM). These findings indicate that acute hypertension, mediated via arterial baroreceptors, is a potent stimulus for arousal. In intact lambs, the arousal probability increased and arousal time decreased with increasing stimulus strength (1-30 mmHg), but the arousal time difference between QS and REM remained constant. Consideration of these findings in terms of a simple baroreflex threshold model suggests that the slower response in REM sleep is explained by slower neural processes after the achievement of a critical arousal input rather than by a higher threshold for baroreceptor input in this state.

Invisible Adaptation: The Effect of Awareness on the Strength of the Motion Aftereffect

Perception ◽  
2020 ◽  
Vol 49 (8) ◽  
pp. 835-857
Author(s):  
Daphne Roumani ◽  
Konstantinos Moutoussis
Keyword(s):  
Visual Processing ◽  
Discrimination Task ◽  
Motion Aftereffect ◽  
Stimulus Strength ◽  
Perceptual Awareness ◽  
Physical Stimulus ◽  
Adaptation Stimulus ◽  
Unconscious Processing ◽  
Total Absence ◽  
Direction Discrimination

The ability to process information despite the lack of perceptual awareness is one of the most fascinating aspects of the visual system. Such unconscious processing is often investigated using adaptation, where any presence of the former can be traced by its footprint on aftereffects following the latter. We have investigated the mechanisms of the motion aftereffect (MAE) using random dot displays of varying motion coherence as well as crowding to modulate both the physical as well as the perceptual strength of the adaptation stimulus. Perceptual strength was quantitatively measured as the performance in a forced-choice direction-discrimination task. A motion-nulling technique was used to quantitatively measure the strength of the MAE. We show that the strength of the dynamic MAE is independently influenced by both the physical stimulus strength as well as the subjective perceptual strength, with the effect of the former being more prominent than that of the latter. We further show that the MAE still persists under conditions of subthreshold perception. Our results suggest that perceptual awareness can influence the strength of visual processing, but the latter is not fully dependent on the former and can still take place at its partial or even total absence.

Sign in / Sign up

Export Citation Format

Share Document