The Effect of Stationary Patterns on Adaptation for Movement: Evidence for Inhibitory Interaction

Perception ◽  
1975 ◽  
Vol 4 (3) ◽  
pp. 311-329 ◽  
Author(s):  
John E W Mayhew
Keyword(s):  
Test Pattern ◽  
Threshold Elevation ◽  
Inhibitory Interaction ◽  
Movement Aftereffect ◽  
Specific Adaptation ◽  
Neural Processes ◽  
Stationary Test ◽  
Simple Movement ◽  
Moving Patterns ◽  
Moving Pattern

Contingent movement aftereffects (CMAEs) can be demonstrated by adapting to a red pattern rotating clockwise (cw) alternating with a green pattern rotating counterclockwise (ccw). After 5 min subjects typically report stationary test patterns as apparently rotating clockwise when they are green and counterclockwise when they are red. Also, luminance thresholds for motion now depend on both the colour and direction of the moving pattern. The thresholds for red—cw and green—ccw motion will be relatively greater than for the opposite colour motion pairings. This is called contingent threshold elevation. When stationary dots the same colour as the moving patterns are added to the adapting stimuli, subjects report weak CMAEs but no contingent threshold elevation can be demonstrated. When stationary dots opposite in colour to the moving patterns are added to the adapting stimuli, neither CMAEs nor contingent threshold elevation can be demonstrated. And yet colour specific adaptation does occur, and can be demonstrated in the colour specificity of the simple movement aftereffect. When stationary dots are added to the adapting pattern, the simple movement aftereffect though reduced, is greatest on a test pattern of the same colour as the moving dots. These findings suggest that the CMAE, contingent threshold elevation, and the colour specificity of the movement aftereffect involves neural processes differentially sensitive to the presence of stationary patterns.

A Transparent Motion Aftereffect Contingent on Binocular Disparity

Perception ◽  
1994 ◽  
Vol 23 (10) ◽  
pp. 1181-1188 ◽  
Author(s):  
Frans A J Verstraten ◽  
Reinder Verlinde ◽  
R Eric Fredericksen ◽  
Wim A van de Grind
Keyword(s):  
Binocular Disparity ◽  
Motion Aftereffect ◽  
Stimulus Configuration ◽  
Retinal Disparity ◽  
Transparent Motion ◽  
Stationary Test ◽  
Vector Sum ◽  
Moving Patterns

Under transparent motion conditions overlapping surfaces are perceived simultaneously, each with its own direction. The motion aftereffect (MAE) of transparent motion, however, is unidirectional and its direction is opposite to that of a sensitivity-weighted vector sum of both inducing vectors. Here we report a bidirectional and transparent MAE contingent on binocular disparity. Depth (from retinal disparity) was introduced between two patterns. A fixation dot was presented at zero disparity, that is, located between the two adaptation patterns. After adaptation to such a stimulus configuration testing was carried out with two stationary test patterns at the same depths as the preceding moving patterns. For opposite directions a clear transparent MAE was perceived. However, if the adaptation directions were orthogonal the chance of a transparent MAE being perceived decreased substantially. This was subject dependent. Some subjects perceived an orthogonal transparent MAE whereas others saw the negative vector sum—an integrated MAE. In addition the behaviour of the MAE when the distance in depth between adapting and test patterns was increased was investigated: it was found that the visibility of the MAE then decreased. Visibility is defined in this paper as: (i) the percentage of the trials in which MAEs are perceived and (ii) the average MAE duration. Both measures decreased with increasing distance. The results suggest that segregation and integration may be mediated by direction-tuned channels that interact with disparity-tuned channels.

scholarly journals Spatiotemporal Identification of Moving Patterns on a Fingertip-based Electro-Tactile Display Array

2020 ◽  
Author(s):  
Mehdi Rahimi ◽  
Fang Jiang ◽  
Yantao Shen
Keyword(s):  
Communication Channel ◽  
Detection Threshold ◽  
Electrical Signal ◽  
Electrical Contacts ◽  
Tactile Display ◽  
Sensory Substitution ◽  
Substitution System ◽  
Specific Order ◽  
Moving Patterns ◽  
Moving Pattern

An electro-tactile display can be used to stimulate sensations in the skin. The ultimate achievement in this area is to open a new information communication channel using this sensory substitution system. One of the requirement of such communication channel is to deliver meaningful commands to the user. The sensations should be distinctive enough to be readily understandable for the operator.<br>This study is perusing the feasibility of generating identifiable moving patterns in the electro-tactile display. Then, the degree of identification performed by the users will be validated.<br><br>An electro-tactile display is built using an array of sixteen contacts to form a moving pattern by delivering electrical signal to the fingertip skin.<br>This signal can have varying voltages, frequencies or duty cycles to form the most comfortable sensation.<br>Moving patterns can be generated by individually or collectively toggling the electrical contacts on the electro-tactile display. This will achieve a stimulation of a moving pattern. In this regard, a moving pattern can be compared to a set of frame-by-frame pictures that construct a movie. Similarly, by toggling the contacts in a specific order, a moving pattern can be achieved.<br><br>In this study, eight subjects participated. A questionnaire was used to assess the sensation of the corresponding movement.<br>The results of these reports were analyzed and a conclusion regarding the identification of the direction of the movement was drawn. It became clear that the direction of the movement had a significant impact on the recognition of the patterns.<br><br>Furthermore, an analysis of the detection threshold (DT) voltage and current mapping was performed to evaluate the effect of the internal structure of the skin for each user on the assessment performance.<br>Based on the mapping results, it became clear that the DT voltage is vastly different for each contact and the resulting spatial map is also unique to each user.

scholarly journals Spatiotemporal Identification of Moving Patterns on a Fingertip-based Electro-Tactile Display Array

2020 ◽  
Author(s):  
Mehdi Rahimi ◽  
Fang Jiang ◽  
Yantao Shen
Keyword(s):  
Communication Channel ◽  
Detection Threshold ◽  
Electrical Signal ◽  
Electrical Contacts ◽  
Tactile Display ◽  
Sensory Substitution ◽  
Substitution System ◽  
Specific Order ◽  
Moving Patterns ◽  
Moving Pattern

An electro-tactile display can be used to stimulate sensations in the skin. The ultimate achievement in this area is to open a new information communication channel using this sensory substitution system. One of the requirement of such communication channel is to deliver meaningful commands to the user. The sensations should be distinctive enough to be readily understandable for the operator.<br>This study is perusing the feasibility of generating identifiable moving patterns in the electro-tactile display. Then, the degree of identification performed by the users will be validated.<br><br>An electro-tactile display is built using an array of sixteen contacts to form a moving pattern by delivering electrical signal to the fingertip skin.<br>This signal can have varying voltages, frequencies or duty cycles to form the most comfortable sensation.<br>Moving patterns can be generated by individually or collectively toggling the electrical contacts on the electro-tactile display. This will achieve a stimulation of a moving pattern. In this regard, a moving pattern can be compared to a set of frame-by-frame pictures that construct a movie. Similarly, by toggling the contacts in a specific order, a moving pattern can be achieved.<br><br>In this study, eight subjects participated. A questionnaire was used to assess the sensation of the corresponding movement.<br>The results of these reports were analyzed and a conclusion regarding the identification of the direction of the movement was drawn. It became clear that the direction of the movement had a significant impact on the recognition of the patterns.<br><br>Furthermore, an analysis of the detection threshold (DT) voltage and current mapping was performed to evaluate the effect of the internal structure of the skin for each user on the assessment performance.<br>Based on the mapping results, it became clear that the DT voltage is vastly different for each contact and the resulting spatial map is also unique to each user.

Movement Aftereffects Contingent on Binocular Disparity

Perception ◽  
1974 ◽  
Vol 3 (2) ◽  
pp. 153-168 ◽  
Author(s):  
S M Anstis ◽  
J P Harris
Keyword(s):  
Binocular Disparity ◽  
Total Duration ◽  
Test Field ◽  
Movement Aftereffect ◽  
Elapsed Time ◽  
Uncrossed Disparity ◽  
Stationary Test ◽  
Time Movement

Five subjects adapted for 30 min to a textured disc lying in front of the fixation point with 0·1 deg(1) crossed disparity, which rotated clockwise at 4 rev/min, alternating with a disc behind the fixation point, with 0·1 deg of arc uncrossed disparity, which rotated anticlockwise. A stationary test field then appeared to rotate anticlockwise when it lay in front of the fixation point, and clockwise when it lay behind. Conversely, a test field in the plane of fixation briefly appeared to lie a few millimetres behind the fixation plane when it rotated clockwise, and in front when it rotated anticlockwise. The movement aftereffect contingent on disparity reappeared each time the test disparity was reversed, but the total duration of each successive aftereffect in the series decreased exponentially with elapsed time. Movement aftereffects contingent on disparity were very much stronger than those contingent on colour and won out over them when disparity was pitted against colour.

Motion Adaptation from Surrounding Stimuli

Perception ◽  
1991 ◽  
Vol 20 (6) ◽  
pp. 703-714 ◽  
Author(s):  
Qasim Zaidi ◽  
W L Sachtler
Keyword(s):  
Scattered Light ◽  
Adaptation Effect ◽  
Threshold Elevation ◽  
Motion Adaptation ◽  
Simple Motion ◽  
Test Region ◽  
Retinal Region ◽  
Moving Stimulus ◽  
Contrast Thresholds ◽  
Moving Pattern

When a narrow uniform gap was surrounded by a moving grating, the gap appeared as a grating in the opposite phase to that of the surround, moving in the same direction with the same speed. Contrast thresholds for moving test-gratings placed in the region of the uniform gap were found to be elevated after prolonged viewing of this pattern, thus demonstrating the existence of motion adaptation in a retinal region surrounded by, but not covered by, a moving pattern. The amplitude of the moving induced-grating was measured by nulling with a real grating moving in the same direction and with the same speed as the surround. When the speed of the inducing grating was varied, the amplitude of the induced effect did not correlate with the magnitude of the threshold elevation. Therefore, it is unlikely that motion adaptation in the uniform gap was due to induced gratings. In some conditions, the adaptation effect of surrounding gratings was no less than the adaptation effect of gratings covering the test region. This result rules out an explanation involving scattered light, and indicates that motion adaptation occurs at a later stage than that consisting of simple motion mechanisms which confound the contrast and velocity of a moving stimulus.

scholarly journals The hierarchy of directional interactions in visual motion processing

2008 ◽  
Vol 276 (1655) ◽  
pp. 263-268 ◽  
Author(s):  
William Curran ◽  
Colin W.G Clifford ◽  
Christopher P Benton
Keyword(s):  
Visual Motion ◽  
Neural Substrates ◽  
The Other ◽  
Motion Processing ◽  
Perceptual Representation ◽  
Motion Direction ◽  
Visual Motion Processing ◽  
Neural Processes ◽  
After Effect ◽  
Moving Pattern

It is well known that context influences our perception of visual motion direction. For example, spatial and temporal context manipulations can be used to induce two well-known motion illusions: direction repulsion and the direction after-effect (DAE). Both result in inaccurate perception of direction when a moving pattern is either superimposed on (direction repulsion), or presented following adaptation to (DAE), another pattern moving in a different direction. Remarkable similarities in tuning characteristics suggest that common processes underlie the two illusions. What is not clear, however, is whether the processes driving the two illusions are expressions of the same or different neural substrates. Here we report two experiments demonstrating that direction repulsion and the DAE are, in fact, expressions of different neural substrates. Our strategy was to use each of the illusions to create a distorted perceptual representation upon which the mechanisms generating the other illusion could potentially operate. We found that the processes mediating direction repulsion did indeed access the distorted perceptual representation induced by the DAE. Conversely, the DAE was unaffected by direction repulsion. Thus parallels in perceptual phenomenology do not necessarily imply common neural substrates. Our results also demonstrate that the neural processes driving the DAE occur at an earlier stage of motion processing than those underlying direction repulsion.

Strength of Motion Aftereffect Varies with Segregation of Test Field and Surround

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 64-64 ◽  
Author(s):  
J P Harris ◽  
D Sullivan
Keyword(s):  
Visual Motion ◽  
Test Pattern ◽  
Motion Aftereffect ◽  
Auditory Signal ◽  
Test Field ◽  
Rectangular Window ◽  
Stationary Test ◽  
Two Measures ◽  
Motion Detectors ◽  
Good Agreement

It is widely accepted that the motion aftereffect (MAE) results from the adaptation of visual motion detectors. However, recent work suggests that how the effects of that adaptation are expressed (the nature of the perceived MAE) depends on the nature of the inducing and test fields. We investigated how the strength of the MAE varied with the nature of the boundary between the test field and the surround. The surround (18.5 deg wide × 13.5 deg high) to the adapting and test fields was an area of vertical square-wave grating of 0.7 cycle deg−1. During adaptation, vertical stripes of the same spatial frequency as the background moved horizontally at a speed of 2 deg s−1 for 14 s within a central rectangular window of 9.7 deg wide × 7.6 deg high. At the end of adaptation, one of six different test fields was presented in the central window. In three of these, the stationary test stripes were exactly aligned with the surrounding stripes, and in the other three they were offset by half a stripe width. For two of these conditions (one aligned, one offset), a black outline was drawn around the edge of the adapting window (and so was visible only where it crossed white areas), and for two others (one aligned, one offset) the outline was red, and so visible in its entirety. The strength of MAEs in twelve subjects was assessed both by ratings at an auditory signal which occurred 0.5 s after the end of adaptation and also by measurement of their durations. There was good agreement between these two measures. MAEs were significantly stronger on the offset than on the aligned test fields. The presence of an outline increased MAE strength compared with no outline, but these outline effects were much weaker than those of offsetting the test stripes from the surround. We suggest that the MAE depends in part on the presence of a visually separable test pattern to which motion may be allocated.

Generation of Locomotive Patterns and Self-Organization

1992 ◽  
Vol 4 (2) ◽  
pp. 142-147 ◽  
Author(s):  
Hideo Yuasa ◽  
◽  
Masami Ito
Keyword(s):  
Gait Pattern ◽  
Pattern Generator ◽  
Rhythmic Movements ◽  
Generator System ◽  
Gait Patterns ◽  
Temporal And Spatial ◽  
Moving Patterns ◽  
Synthesis Approach ◽  
Moving Pattern ◽  
Moving Speed

Rhythmic movements of walking, swimming, etc. are controlled by mutually coupled endogenous neural oscillators. These rhythms coordinate one another to generate temporal and spatial moving patterns suitable for their environments and purposes. For example, a cat moves faster, the gait patterns change from “walk” to “trot”, and lastly to “gallop”. This moving pattern generator system can be regarded as one of the autonomous distributed systems which generates global patterns suitable for their environments and purposes. Using the bifurcation theory, it is possible to construct a system that suitably changes patterns discontinuously when a parameter changes continuously. This synthesis approach is applied to make a gait pattern generator system of a quadruped artificially. A gait pattern generator is constructed to couple four oscillators in which each oscillating state is regarded as each limb’s rhythmic motion. It is shown using computer simulations that the proposed system generates and changes patterns suitable for its moving speed; i.e. “walk”, “trot” and “gallop”.

Speed Judgments of Transparent Stimuli

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 107-107
Author(s):  
J B Mulligan
Keyword(s):  
Test Pattern ◽  
Random Noise ◽  
Discrimination Performance ◽  
Mask Condition ◽  
Mask Pattern ◽  
Standard Pattern ◽  
Band Pass ◽  
Speed Discrimination ◽  
Moving Patterns ◽  
Direction Opposite

When two moving patterns are combined additively, observers often perceive two transparent surfaces, even when there are no cues supporting this segmentation in a frozen snapshot. The ability of observers to make quantitative judgments about the speed of one of the patterns under these conditions was examined. The component patterns consisted of band-pass-filtered random noise presented in a spatial Gaussian contrast envelope, displayed for 250 ms. On each trial a standard pattern appeared on one side of the fixation point, while a test pattern appeared on the other. The test pattern moved in the same direction as the standard, but with a speed which varied from trial to trial according to a staircase procedure. The subjects' task was to report the side of the fixation point on which faster motion was seen. In some conditions the test stimulus was made to appear transparent by adding a mask pattern. When the mask was stationary, or moved slowly with respect to the test, no significant biases were introduced and discrimination performance was comparable to the no-mask condition (typically 3%). But if the mask moved over the test with similar speed, the task became much harder, regardless of whether the mask moved in a direction opposite or orthogonal to the test. (Some subjects commented on a perceived directional repulsion between tests and orthogonally moving masks.) These results suggest the use of nondirectional temporal channels in the performance of the speed discrimination task.

Ultrastructural study on the development of rat amygdaloid body

1990 ◽  
Vol 48 (3) ◽  
pp. 432-433
Author(s):  
A. Manolova ◽  
S. Manolov
Keyword(s):  
Nerve Cells ◽  
Amygdaloid Complex ◽  
Amygdaloid Body ◽  
Thin Ring ◽  
Morphological Criteria ◽  
Neural Processes ◽  
Abundant Cytoplasm ◽  
Level 1 ◽  
Few Data ◽  
Oval Shape

Relatively few data on the development of the amygdaloid complex are available only at the light microscopic level (1-3). The existence of just general morphological criteria requires the performance of other investigations in particular ultrastructural in order to obtain new and more detailed information about the changes in the amygdaloid complex during development.The prenatal and postnatal development of rat amygdaloid complex beginning from the 12th embrionic day (ED) till the 33rd postnatal day (PD) has been studied. During the early stages of neurogenesis (12ED), the nerve cells were observed to be closely packed, small-sized, with oval shape. A thin ring of cytoplasm surrounded their large nuclei, their nucleoli being very active with various size and form (Fig.1). Some cells possessed more abundant cytoplasm. The perikarya were extremely rich in free ribosomes. Single sacs of the rough endoplasmic reticulum and mitochondria were observed among them. The mitochondria were with light matrix and possessed few cristae. Neural processes were viewed to sprout from some nerve cells (Fig.2). Later the nuclei were still comparatively large and with various shape.

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