Temporal Properties of the Short-Range Process in Apparent Motion

Perception ◽  
1985 ◽  
Vol 14 (2) ◽  
pp. 181-192 ◽  
Author(s):  
Curtis L Baker ◽  
Oliver J Braddick
Keyword(s):  
Motion Perception ◽  
Apparent Motion ◽  
Motion Detection ◽  
Interstimulus Interval ◽  
Short Range ◽  
Time Interval ◽  
Optimal Motion ◽  
Temporal Properties ◽  
Range Process

A study is reported of the perception of random-dot two-frame apparent motion in which the durations of each exposure and the interstimulus interval between them were varied. The results are largely consistent with the rule that, for optimal motion detection, a portion of each exposure must fall within the same time interval of about 40 ms. In addition, motion perception is separably dependent on the displacement from one exposure to the next and on the time interval between those exposures, rather than on the ‘velocity implied by their ratio.

Temporal Properties of Apparent Motion in Subjective Figures

Perception ◽  
1988 ◽  
Vol 17 (6) ◽  
pp. 729-736 ◽  
Author(s):  
George Mather
Keyword(s):  
Apparent Motion ◽  
Motion Detection ◽  
Time Interval ◽  
Temporal Properties ◽  
Motion Process ◽  
Motion Percept ◽  
High Level ◽  
Level Process

In ‘Kanizsa’ figures, vivid subjective shapes are seen in the absence of explicit contours to define them. When two or more such figures are presented sequentially, so that the subjective shape occupies different positions, good apparent motion of the shape is usually reported. This motion percept must be mediated by a high-level process, in which form extraction precedes motion detection. Some spatial and temporal properties of this motion process are investigated. A major finding is that motion is only perceived when the time interval between successive frames falls below about 500 ms, and the duration of each frame exceeds about 80 ms.

Failure to find an absolute retinal limit of a putative short-range process in apparent motion

1983 ◽  
Vol 23 (12) ◽  
pp. 1663-1670 ◽  
Author(s):  
J. Timothy Petersik ◽  
Randall Pufahl ◽  
Elizabeth Krasnoff
Keyword(s):  
Apparent Motion ◽  
Short Range ◽  
Range Process

scholarly journals Are there separate ON and OFF channels in fly motion vision?

1992 ◽  
Vol 8 (2) ◽  
pp. 151-164 ◽  
Author(s):  
Martin Egelhaaf ◽  
Alexander Borst
Keyword(s):  
Visual Field ◽  
Apparent Motion ◽  
Motion Detection ◽  
Visual Information ◽  
Detection System ◽  
Time Interval ◽  
Motion Vision ◽  
Response Component ◽  
Retinal Input ◽  
Motion Detection System

AbstractVisual information is processed in a series of subsequent steps. The performance of each of these steps depends not only on the computations it performs itself but also on the representation of the visual surround on which it operates. Here we investigate the consequences of signal preprocessing for the performance of the motion-detection system of the fly. In particular, we analyze whether the retinal input signals are rectified and segregate into separate ON and OFF channels, which then feed independent parallel motion-detection pathways. We recorded the activity of an identified directionally selective interneuron (HI-cell) in response to apparent motion stimuli, i.e. sequential brightness changes at two neighboring locations in the visual field, as well as to brightness changes at only a single location. For apparent motion stimuli, the motion-dependent response component was determined by subtracting from the overall response the responses to the individual stimulus components when presented alone. The following conclusions could be derived: (1) Apparent motion consisting of a sequence of increased or decreased brightness at two locations in the visual field have the same optimum interstimulus time interval (Fig. 3). (2) Sequences of brightness steps of like polarity (either increments or decrements) elicit positive and negative motion-dependent response components when mimicking motion in the cell's preferred and null direction, respectively. The motion-dependent response components are inverted in sign when the brightness steps of a stimulus sequence have a different polarity (Fig. 7). (3) The responses to the beginning and the end of a brightness pulse depend on the pulse duration. For pulse durations of less than 2 s, both events interact with each other (Fig. 9). All of these results do not provide any indication that the fly processes motion information in independent ON and OFF motion detectors. Brightness changes of both signs are rather represented at the input of the same movement detectors, and interactions between signals resulting from both brightness increments and decrements take their sign into account. This type of preprocessing of the retinal input is argued to render a motion-detection system particularly robust against noise.

Eccentricity-dependent scaling of the limits for short-range apparent motion perception

1985 ◽  
Vol 25 (6) ◽  
pp. 803-812 ◽  
Author(s):  
Curtis L. Baker ◽  
Oliver J. Braddick
Keyword(s):  
Motion Perception ◽  
Apparent Motion ◽  
Short Range

A short-range process in apparent motion

1974 ◽  
Vol 14 (7) ◽  
pp. 519-527 ◽  
Author(s):  
Oliver Braddick
Keyword(s):  
Apparent Motion ◽  
Short Range ◽  
Range Process

Effects of Luminance and Contrast on Direction of Ambiguous Apparent Motion

Perception ◽  
1985 ◽  
Vol 14 (2) ◽  
pp. 167-179 ◽  
Author(s):  
Stuart M Anstis ◽  
George Mather
Keyword(s):  
Apparent Motion ◽  
Interstimulus Interval ◽  
Short Range ◽  
Light Stimulus ◽  
Motion Aftereffect ◽  
The Other ◽  
Visual Response ◽  
Spatial Displacement ◽  
Negative Aftereffect

A study is reported of the role of luminance and contrast in resolving ambiguous apparent motion (AM). Different results were obtained for the short-range (SR) and the long-range (LR) motion-detecting processes. For short-range jumps (7.5 min arc), the direction of ambiguous AM depended on brightness polarity, with AM only from white to white and from black to black. But for larger jumps, or when an interstimulus interval (ISI) was introduced, AM was less dependent on polarity, with white often jumping to black and black jumping to white. Two potential AMs were pitted against each other, one carried by a light stimulus and the other by a dark stimulus. The stimulus whose luminance differed most from the uniform surround captured the AM. Visual response to luminance was linear, not logarithmic. When the stimulus was modified to give continuous AM in one direction it was followed by a negative aftereffect of motion only when the spatial displacement was 1 min arc. A larger displacement (10 min arc) gave good AM but no motion aftereffect. Thus only short-range motion adapts motion-sensitive channels.

Neurobiological correlates of apparent motion perception in the human visual system using magnetoencephalography

NeuroImage ◽  
2001 ◽  
Vol 13 (6) ◽  
pp. 893
Author(s):  
C.I. Horenstein ◽  
R.R. Ramirez ◽  
E. Kronberg ◽  
U. Ribary ◽  
R.R. Llinas
Keyword(s):  
Visual System ◽  
Motion Perception ◽  
Apparent Motion ◽  
Human Visual System

Mechanical properties of cat soleus muscle elicited by sequential ramp stretches: implications for control of muscle

1993 ◽  
Vol 70 (3) ◽  
pp. 997-1008 ◽  
Author(s):  
D. C. Lin ◽  
W. Z. Rymer
Keyword(s):  
Soleus Muscle ◽  
Constant Velocity ◽  
Short Range ◽  
Single Pulse ◽  
Fold Increase ◽  
Elastic Behavior ◽  
Time Interval ◽  
Mechanical Stiffness ◽  
Initial Portion ◽  
High Stiffness

1. Force changes in areflexive cat soleus muscle in decerebrate cats were recorded in response to two sequential constant velocity (ramp) stretches, separated by a variable time interval during which the length was held constant. Initial (i.e., prestretch) background force was generated by activating the crossed-extension reflex, and stretch reflexes were eliminated by section of ipsilateral dorsal roots. 2. For the initial 400-900 microns of the first stretch, the muscle exhibited high stiffness, classically termed "short-range stiffness." This high stiffness region was followed by an abrupt reduction in stiffness, called muscle "yield," after which force remained at a relatively constant level, achieving a plateau in force. This plateau force level depended largely on stretch velocity, but this dependence was much less than proportional to the increase in stretch velocity, in that a 10-fold increase in velocity produced < 2-fold increase in plateau force. 3. In experiments where the velocities of the two sequential ramp stretches were identical, the force plateau level was the same for each stretch, regardless of the time elapsed before the second stretch (varied from 0 to 500 ms). In contrast, measures of stiffness during the initial portion of the second stretch showed time-dependent magnitude reductions. However, stiffness recovered quickly after the first stretch was completed, returning to control values within 30-40 ms. 4. In one preparation, in which the velocities of the two sequential ramp stretches were different, the force plateau elicited during the second stretch exhibited velocity dependence comparable with that recorded in the earlier single velocity studies. Furthermore, muscle yield was still evident in the case where the force change was due solely to the change in velocity and where short-range stiffness had not yet recovered fully from the initial stretch. On the basis of these findings, we argue that the classical descriptions of short-range stiffness and yield are inadequate and that the change in force that has typically been called the muscle yield reflects a transition between short-range, transient elastic behavior to steady-state, essentially viscous behavior. 5. To examine changes in the muscle's mechanical stiffness during single ramp stretches, a single pulse perturbation was superimposed at various times before, during, and subsequent to the constant velocity stretch. The force increment elicited in response to each pulse decreased relative to the initial isometric value, remained essentially constant until the end of the ramp, and then returned to its prestretch magnitude shortly (30-40 ms) after stretch termination.(ABSTRACT TRUNCATED AT 400 WORDS)

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