The effect of retinal illuminance on visual motion priming (original) (raw)
Related papers
The reference frame of visual motion priming depends on underlying motion mechanisms
Journal of Vision, 2014
Several different types of motion mechanisms function in the human visual system. The purpose of this study was to clarify the type of reference frame, such as retinotopic and spatiotopic frames of reference, at which those different motion mechanisms function. To achieve this, we used a phenomenon called visual motion priming, in which the perceived direction of a directionally ambiguous test stimulus is influenced by the moving direction of a preceding stimulus. Previous studies have indicated that negative motion priming is induced by a low-level motion mechanism, such as a first-order motion sensor, whereas positive motion priming is induced by a high-level motion mechanism, such as a feature-tracking system. In the experiments, subjects made a saccade after the termination of a smoothly drifting priming stimulus and judged the perceived direction of a 1808 phase-shifted sine-wave grating presented subsequently in retinotopic or screen-based spatiotopic coordinates. By manipulating the stimulus parameters, such as primer duration, velocity, and contrast, both positive and negative priming were observed. We found that positive priming was observed in spatiotopic coordinates, whereas negative priming was observed in retinotopic coordinates. Prominent positive priming in spatiotopic coordinates was observed only when the interval between the priming and test stimuli was longer than around 600 ms. This delayed priming effect was not caused by saccadic eye movements. These results suggest that a low-level motion mechanism functions in retinotopic coordinates, whereas a high-level motion mechanism functions in spatiotopic coordinates, in which the representation builds up slowly.
Probing Visual Motion Signals with a Priming Paradigm
Vision Research, 1997
The perceived motion of a vertical sine-wave luminance grating which undergoes an abrupt 180 deg phase shift (motion step) is ambiguous. The grating sometimes appears to move rightward; sometimes Ieftward. However, when the 180 deg step follows closely upon an unambiguous grating step, the 180 deg step appears to be in the same direction as the unambiguous step. This phenomenon is termed visual motion priming (VMP), and some of the characteristics of the phenomenon were investigated in a series of experiments. The main findings were that priming (1) lasted for hundreds of msec; (2) was at a maximum when the magnitude of the priming step was 90 deg; (3) was scarcely affected by spatial frequency in the range 0.7-2.8 c/deg; and (4) at suprathreshold contrasts depended upon the relative contrast, not the absolute contrasts, of the frames comprising the priming step. The experiments were conducted within the framework of a motion energy model (Adelson & Bergen, 1985) which possessed an extra stage which summed motion signals over time. Some of the results could be explained by the second-stage integrator. Other nonlinear relationships between VMP and contrast require some form of motion signal compression, and perhaps even a mechanism of dynamic contrast processing.
Effect of light level on the reference frames of visual motion processing
Journal of vision, 2014
It is empirically known that some action-related visual tasks, which may rely on the construction of spatiotopic coordinates, are not well conducted under mesopic vision. The aim of this study was to clarify the effect of light level on the reference frame, such as retinotopic and spatiotopic coordinate bases, associated with visual motion processing. For this purpose, we used a phenomenon called visual motion priming in which the perceived direction of a directionally ambiguous test stimulus is influenced by the moving direction of a priming stimulus. Previous studies have shown that negative and positive motion priming are conspicuously observed in retinotopic and spatiotopic coordinates, respectively. In the experiments, participants made a saccade after the termination of the priming stimulus and judged the perceived direction of the test stimulus presented subsequently in retinotopic or spatiotopic coordinates at different light levels. We found that in retinotopic coordinates,...
Perceived motion in orientational afterimages: direction and speed
Vision Research, 2001
Two sets of experiments demonstrate new properties of motion in orientational after-effects. In a previous report, we showed that when observers adapted to a static bar grating whose elements varied in size or intensity from one side to the other, offset of the grating resulted in a motion after-effect, with the perceived motion in the direction of the largest or most intense bar. In the first new experiment, we show that similar results can be produced by varying the duration of the bar elements, with the direction of the motion after-effect toward the bar with the longest duration. In the second new experiment we demonstrate that the perceived speed of the motion aftereffect is influenced by the spatial extent of the after-effect, with larger extents corresponding to faster speeds. The experimental findings are discussed in the context of a neural network theory of visual perception. In this theory, a moving oriented contour leaves a trail of activity among cortical cells tuned to orthogonal orientations. We hypothesize that the grating stimuli produce after-effects that mimic the pattern of oriented responses produced by a true moving contour, and the visual system interprets this pattern as a cue for motion. We also show how the model connects the properties of these motion after-effects to properties of visual persistence.
Journal of Vision, 2009
Fast adaptation biases the perceived motion direction of a subsequently presented ambiguous test pattern (R. . Depending on both the duration of the adapting stimulus (ranging from tens to hundreds of milliseconds) and the duration of the adaptation-test blank interval, the perceived direction of an ambiguous test pattern can be biased towards the same or the opposite direction of the adaptation pattern, resulting in rapid forms of motion priming or motion aftereffect respectively. These findings were obtained employing drifting luminance gratings. Many studies have shown that first-order motion (luminance-defined) and second-order motion (contrast-defined) stimuli are processed by separate mechanisms. We assessed whether these effects also exist within the second-order motion domain. Results show that fast adaptation to second-order motion biases the perceived direction of a subsequently presented second-order ambiguous test pattern with similar time courses to that obtained for first-order motion. To assess whether a single mechanism could account for these results, we ran a cross-order adaptation condition. Results showed little or no transfer between the two motion cues and probes, suggesting a degree of separation between the neural substrates subserving fast adaptation of firstand second-order motion. mechanisms for firstand second-order patterns revealed by rapid forms of visual motion priming and motion aftereffect.
Visual resolution of motion ambiguity with periodic luminance- and contrast-domain stimuli
Vision Research, 1992
Visual moron procemes were studied witb buninance-and eon~~~a~ gratings. A sine-wave luminance grating was displaced abruptly back aud forth by & cycle. The display sequence is ambiguous in that each &-cycle phase shift (short-path motion) could just as readily be seen as a z-cycle sbift (long-path motion) in the opposite direction. By varying the duration of the interval (IFI) between the two phase positions, the luminance of the IFI, or the spatial frequency of tbe grating, it was possible to bias tbe ambiguous percept in favor of short-path motions or loug-patb motions. A ~n~~-rn~~at~ grating displaced through 2 cycle aIways appeared to Ilscterp(o sbort-patb motion. Current motion models which incorporate Reicbardt-type/energy meckanhmm and certain types of auxiliary signal transformations which precede those mecbauisms do not adeqaately explain the effects of IF1 intensity on the perceived motion of a sinusoidal grating or tbe effect of IFI duration on the perceived motion of a contrast-modulated grating.
Rapid serial visual presentation of motion: Short-term facilitation and long-term suppression
2011
The visual system can detect coherent motion in the midst of motion noise. This is accomplished with motion-sensitive channels, each of which is tuned to a limited range of motion directions. Our aim was to show how a single channel is affected by motions both within and outside its tuning range. We used a psychophysical reverse-correlation procedure. An array of dots moved coherently with a new, randomly chosen, direction every 14 or 28 ms. Human subjects pressed a key whenever they saw upwards movement. The results were analyzed by finding two motion directions before each key-press: the first preceded the key-press by the reaction time, and the second preceded the first by a variable interval. There were two main findings. First, the subject was significantly more likely to press the key when the vector average of the two motions was in the target direction. This effect was short-lived: it was only seen for inter-stimulus intervals of several tens of milliseconds. Second, motion detection was reduced when the target direction was preceded by a motion of similar direction 100-200 ms earlier. The results support the idea that a motion-sensitive channel sums sub-optimal inputs, and is suppressed by similar motion in the long term.
Simultaneity and sequence in the perception of apparent motion
Attention, Perception & Psychophysics, 2009
Motion perception usually is accompanied by the phenomenological impression of sequence as objects move through successions of locations. Nonetheless, there is accumulating evidence that sequential information is neither necessary nor sufficient for perceiving motion. It is shown here that apparent motion is specified by counterchange rather than sequence-that is, by co-occurring toward-and away-from-background changes at two spatial locations, regardless of whether the changes are simultaneous or sequential. Motion is perceived from the location of the toward to the location of the away change, even when the changes occur in reverse temporal order. It is not perceived for sequences of away or toward changes, as would be expected if motion were specified by onset or offset asynchronicity. Results previously attributed to onset and offset asynchrony are instead attributable to onsets and offsets occurring in close temporal proximity at the same location. This was consistent with units for detecting away and toward changes that are temporally biphasic; that is, they are excited by changes in one direction and inhibited by immediately preceding or immediately following changes in the opposite direction. These results are accounted for by a model for counterchange-specified motion entailing the biphasic detection of toward and away changes.
Temporal facilitation for moving stimuli is independent of changes in direction
2000
A flash that is presented aligned with a moving stimulus appears to lag behind the position of the moving stimulus. This flash-lag phenomenon reflects a processing advantage for moving stimuli (The present study measures the sensitivity of the illusion to unpredictable changes in the direction of motion. A moving stimulus translated upwards and then made a 90°turn leftward or rightward. The flash-lag illusion was measured and it was found that, although the change in direction was unpredictable, the flash was still perceived to lag behind the moving stimulus at all points along the trajectory, a finding that is at odds with the extrapolation hypothesis (Nijhawan, R. (1994) Nature 370, 256 -257). The results suggest that there is a shorter latency of the neural response to motion even during unpredictable changes in direction. The latency facilitation therefore appears to be omnidirectional rather than specific to a predictable path of motion (Grzywacz, N. M.