scholarly journals Horizontal connectivity in V1 : Prediction of coherence in contour and motion integration

2021 ◽  
Author(s):  
Yves Fregnac ◽  
Benoit Le Bec ◽  
Xoana G. Troncoso ◽  
Christophe Desbois ◽  
Yannick Passarelli ◽  
...  
Keyword(s):  
Apparent Motion ◽  
Propagation Speed ◽  
Flow Speed ◽  
Contextual Control ◽  
Axial Motion ◽  
Global Motion ◽  
Motion Direction ◽  
Orientation Preference ◽  
Speed Range ◽  
Motion Sequence

This study demonstrates the functional importance of the Surround context relayed laterally in V1 by the horizontal connectivity, in controlling the latency and the gain of the cortical response to the feedforward visual drive. We report here four main findings : 1) a centripetal apparent motion sequence results in a shortening of the spiking latency of V1 cells, when the orientation of the local inducer and the global motion axis are both co-aligned with the RF orientation preference; 2) this contextual effects grows with visual flow speed, peaking at 150-250 degrees per second until matching the propagation speed of horizontal connectivity (0.15-0.25 mm/ms); 3) For this speed range, axial sensitivity of V1 cells is tilted by 90 degrees to become co-aligned with the orientation preference axis; 4) the modulation strength by the surround context correlates with the spatiotemporal coherence of the apparent motion flow. Our results suggest an internally-generated binding process, linking local (orientation /position) and global (motion/direction) features as early as V1. This long-range diffusion process constitutes a plausible substrate in V1 of the human psychophysical bias in speed estimate for collinear motion. Since demonstrated in the anesthetized cat, this novel form of contextual control of the cortical transfer function is a built-in property in V1, whose expression does not require behavioral attention and top-down control from higher cortical areas. We propose that horizontal connectivity participates to the propagation of an internal prediction wave, linking contour co-alignment and global axial motion at an apparent speed in the range of saccadic-like eye-movements.

Auditory Motion Induces Directionally Dependent Receptive Field Shifts in Inferior Colliculus Neurons

1998 ◽  
Vol 79 (4) ◽  
pp. 2040-2062 ◽  
Author(s):  
Willard W. Wilson ◽  
William E. O'Neill
Keyword(s):  
Receptive Field ◽  
Inferior Colliculus ◽  
Apparent Motion ◽  
Target Location ◽  
Receptive Fields ◽  
Silent Interval ◽  
Auditory Motion ◽  
Motion Direction ◽  
Motion Sequence ◽  
And Shifts

Wilson, Willard W. and William E. O'Neill. Auditory motion induces directionally dependent receptive field shifts in inferior colliculus neurons. J. Neurophysiol. 79: 2040–2062, 1998. This research focused on the response of neurons in the inferior colliculus of the unanesthetized mustached bat, Pteronotus parnelli, to apparent auditory motion. We produced the apparent motion stimulus by broadcasting pure-tone bursts sequentially from an array of loudspeakers along horizontal, vertical, or oblique trajectories in the frontal hemifield. Motion direction had an effect on the response of 65% of the units sampled. In these cells, motion in opposite directions produced shifts in receptive field locations, differences in response magnitude, or a combination of the two effects. Receptive fields typically were shifted opposite the direction of motion (i.e., units showed a greater response to moving sounds entering the receptive field than exiting) and shifts were obtained to horizontal, vertical, and oblique motion orientations. Response latency also shifted as a function of motion direction, and stimulus locations eliciting greater spike counts also exhibited the shortest neural latency. Motion crossing the receptive field boundaries appeared to be both necessary and sufficient to produce receptive field shifts. Decreasing the silent interval between successive stimuli in the apparent motion sequence increased both the probability of obtaining a directional effect and the magnitude of receptive field shifts. We suggest that the observed directional effects might be explained by “spatial masking,” where the response of auditory neurons after stimulation from particularly effective locations in space would be diminished. The shift in auditory receptive fields would be expected to shift the perceived location of a moving sound and may explain shifts in localization of moving sources observed in psychophysical studies. Shifts in perceived target location caused by auditory motion might be exploited by auditory predators such as Pteronotus in a predictive tracking strategy to capture moving insect prey.

scholarly journals Scrambling the skin: A psychophysical study of adaptation to scrambled tactile apparent motion

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0227462
Author(s):  
Tatjana Seizova-Cajic ◽  
Sandra Ludvigsson ◽  
Birger Sourander ◽  
Melinda Popov ◽  
Janet L. Taylor
Keyword(s):  
Apparent Motion ◽  
Constant Velocity ◽  
Stimulus Onset ◽  
Object Motion ◽  
Local Motion ◽  
Motion Direction ◽  
Good Test ◽  
Motion Sequence ◽  
Velocity Motion ◽  
Perceived Motion

An age-old hypothesis proposes that object motion across the receptor surface organizes sensory maps (Lotze, 19th century). Skin patches learn their relative positions from the order in which they are stimulated during motion events. We propose that reversing the local motion within a global motion sequence (‘motion scrambling’) provides a good test for this idea, and present results of the first experiment implementing the paradigm. We used 6-point apparent motion along the forearm. In the Scrambled sequence, two middle locations were touched in reversed order (1-2-4-3-5-6, followed by 6-5-3-4-2-1, in a continuous loop). This created a double U-turn within an otherwise constant-velocity motion, as if skin patches 3 and 4 physically swapped locations. The control condition, Orderly, proceeded at constant velocity at inter-stimulus onset interval of 120 ms. The 26.4-minute conditioning (delivered in twenty-four 66-s bouts) was interspersed with testing of perceived motion direction between the two middle tactors presented on their own (sequence 3–4 or 4–3). Our twenty participants reported motion direction. Direction discrimination was degraded following exposure to Scrambled pattern and was 0.31 d’ weaker than following Orderly conditioning (p = .007). Consistent with the proposed role of motion, this could be the beginning of re-learning of relative positions. An alternative explanation is that greater speed adaptation occurred in the Scrambled pattern, raising direction threshold. In future studies, longer conditioning should tease apart the two explanations: our re-mapping hypothesis predicts an overall reversal in perceived motion direction between critical locations (for either motion direction), whereas the speed adaptation alternative predicts chance-level performance at worst, without reversing.

Increased internal noise cannot account for motion coherence processing deficits in migraine

Cephalalgia ◽  
2011 ◽  
Vol 31 (11) ◽  
pp. 1199-1210 ◽  
Author(s):  
Kathryn E Webster ◽  
J Edwin Dickinson ◽  
Josephine Battista ◽  
Allison M McKendrick ◽  
David R Badcock
Keyword(s):  
Internal Noise ◽  
Motion Processing ◽  
Global Motion ◽  
Motion Direction ◽  
Significant Group ◽  
Motion Coherence ◽  
Significant Performance ◽  
Efficient Extraction ◽  
Processing Deficits ◽  
Spiral Angle

Aim: This study aimed to revisit previous findings of superior processing of motion direction in migraineurs with a more stringent direction discrimination task and to investigate whether increased internal noise can account for motion processing deficits in migraineurs. Methods: Groups of 13 migraineurs (4 with aura, 9 without aura) and 15 headache-free controls completed three psychophysical tasks: one detecting coherence in a motion stimulus, one discriminating the spiral angle in a glass pattern and another discriminating the spiral angle in a global-motion task. Internal noise estimates were obtained for all tasks using an N-pass method. Results: Consistent with previous research, migraineurs had higher motion coherence thresholds than controls. However, there were no significant performance differences on the spiral global-motion and global-form tasks. There was no significant group difference in internal noise estimates associated with any of the tasks. Conclusions: The results from this study suggest that variation in internal noise levels is not the mechanism driving motion coherence threshold differences in migraine. Rather, we argue that motion processing deficits may result from cortical changes leading to less efficient extraction of global-motion signals from noise.

scholarly journals Rats spontaneously perceive global motion direction of drifting plaids

2021 ◽  
Author(s):  
Giulio Matteucci ◽  
Benedetta Zattera ◽  
Rosilari Bellacosa Marotti ◽  
Davide Zoccolan
Keyword(s):  
Visual Cortex ◽  
Perceived Similarity ◽  
Global Motion ◽  
Motion Direction ◽  
Visual Objects ◽  
Visual Priming ◽  
Priming Paradigm ◽  
High Level ◽  
Mouse Visual Cortex ◽  
Motion Detectors

AbstractComputing global motion direction of extended visual objects is a hallmark of primate high-level vision. Although neurons selective for global motion have also been found in mouse visual cortex, it remains unknown whether rodents can combine multiple motion signals into global, integrated percepts. To address this question, we trained two groups of rats to discriminate either gratings (G group) or plaids (i.e., superpositions of gratings with different orientations; P group) drifting horizontally along opposite directions. After the animals learned the task, we applied a visual priming paradigm, where presentation of the target stimulus was preceded by the brief presentation of either a grating or a plaid. The extent to which rat responses to the targets were biased by such prime stimuli provided a measure of the spontaneous, perceived similarity between primes and targets. We found that gratings and plaids, when uses as primes, were equally effective at biasing the perception of plaid direction for the rats of the P group. Conversely, for G group, only the gratings acted as effective prime stimuli, while the plaids failed to alter the perception of grating direction. To interpret these observations, we simulated a decision neuron reading out the representations of gratings and plaids, as conveyed by populations of either component or pattern cells (i.e., local or global motion detectors). We concluded that the findings for the P group are highly consistent with the existence of a population of pattern cells, playing a functional role similar to that demonstrated in primates. We also explored different scenarios that could explain the failure of the plaid stimuli to elicit a sizable priming magnitude for the G group. These simulations yielded testable predictions about the properties of motion representations in rodent visual cortex at the single-cell and circuitry level, thus paving the way to future neurophysiology experiments.

scholarly journals Direction of Apparent Motion During Smooth Pursuit Is Determined Using a Mixture of Retinal and Objective Proximities

i-Perception ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 204166952093732
Author(s):  
Masahiko Terao ◽  
Shin’ya Nishida
Keyword(s):  
Apparent Motion ◽  
Smooth Pursuit ◽  
Visual Motion ◽  
Motion Path ◽  
Motion Processing ◽  
Motion Direction ◽  
Jump Size ◽  
Perceptual Stability ◽  
Visual Motion Processing ◽  
Selection Of

Many studies have investigated various effects of smooth pursuit on visual motion processing, especially the effects related to the additional retinal shifts produced by eye movement. In this article, we show that the perception of apparent motion during smooth pursuit is determined by the interelement proximity in retinal coordinates and also by the proximity in objective world coordinates. In Experiment 1, we investigated the perceived direction of the two-frame apparent motion of a square-wave grating with various displacement sizes under fixation and pursuit viewing conditions. The retinal and objective displacements between the two frames agreed with each other under the fixation condition. However, the displacements differed by 180 degrees in terms of phase shift, under the pursuit condition. The proportions of the reported motion direction between the two viewing conditions did not coincide when they were plotted as a function of either the retinal displacement or of the objective displacement; however, they did coincide when plotted as a function of a mixture of the two. The result from Experiment 2 showed that the perceived jump size of the apparent motion was also dependent on both retinal and objective displacements. Our findings suggest that the detection of the apparent motion during smooth pursuit considers the retinal proximity and also the objective proximity. This mechanism may assist with the selection of a motion path that is more likely to occur in the real world and, therefore, be useful for ensuring perceptual stability during smooth pursuit.

scholarly journals The direction after-effect is a global motion phenomenon

2019 ◽  
Vol 6 (3) ◽  
pp. 190114
Author(s):  
William Curran ◽  
Lee Beattie ◽  
Delfina Bilello ◽  
Laura A. Coulter ◽  
Jade A. Currie ◽  
...  
Keyword(s):  
Neural Mechanisms ◽  
Motion Processing ◽  
Global Motion ◽  
Local Motion ◽  
Motion Direction ◽  
Processing Level ◽  
True Motion ◽  
Pattern Motion ◽  
Moving Stimulus ◽  
After Effect

Prior experience influences visual perception. For example, extended viewing of a moving stimulus results in the misperception of a subsequent stimulus's motion direction—the direction after-effect (DAE). There has been an ongoing debate regarding the locus of the neural mechanisms underlying the DAE. We know the mechanisms are cortical, but there is uncertainty about where in the visual cortex they are located—at relatively early local motion processing stages, or at later global motion stages. We used a unikinetic plaid as an adapting stimulus, then measured the DAE experienced with a drifting random dot test stimulus. A unikinetic plaid comprises a static grating superimposed on a drifting grating of a different orientation. Observers cannot see the true motion direction of the moving component; instead they see pattern motion running parallel to the static component. The pattern motion of unikinetic plaids is encoded at the global processing level—specifically, in cortical areas MT and MST—and the local motion component is encoded earlier. We measured the direction after-effect as a function of the plaid's local and pattern motion directions. The DAE was induced by the plaid's pattern motion, but not by its component motion. This points to the neural mechanisms underlying the DAE being located at the global motion processing level, and no earlier than area MT.

scholarly journals The integration of local chromatic motion signals is sensitive to contrast polarity

2011 ◽  
Vol 28 (3) ◽  
pp. 239-246 ◽  
Author(s):  
SOPHIE M. WUERGER ◽  
ALEXA RUPPERTSBERG ◽  
STEPHANIE MALEK ◽  
MARCO BERTAMINI ◽  
JASNA MARTINOVIC
Keyword(s):  
Random Motion ◽  
Coherent Motion ◽  
Global Motion ◽  
Local Motion ◽  
Chromatic Contrast ◽  
Motion Direction ◽  
Contrast Polarity ◽  
Motion Integration ◽  
Integration Mechanisms ◽  
Contrast Thresholds

AbstractGlobal motion integration mechanisms can utilize signals defined by purely chromatic information. Is global motion integration sensitive to the polarity of such color signals? To answer this question, we employed isoluminant random dot kinematograms (RDKs) that contain a single chromatic contrast polarity or two different polarities. Single-polarity RDKs consisted of local motion signals with either a positive or a negative S or L–M component, while in the different-polarity RDKs, half the dots had a positive S or L–M component, and the other half had a negative S or L–M component. In all RDKs, the polarity and the motion direction of the local signals were uncorrelated. Observers discriminated between 50% coherent motion and random motion, and contrast thresholds were obtained for 81% correct responses. Contrast thresholds were obtained for three different dot densities (50, 100, and 200 dots). We report two main findings: (1) dependence on dot density is similar for both contrast polarities (+S vs. −S, +LM vs. −LM) but slightly steeper for S in comparison to LM and (2) thresholds for different-polarity RDKs are significantly higher than for single-polarity RDKs, which is inconsistent with a polarity-blind integration mechanism. We conclude that early motion integration mechanisms are sensitive to the polarity of the local motion signals and do not automatically integrate information across different polarities.

scholarly journals Peculiarities of cerebral hemodynamics in patients with early manifestation of insufficient cerebral blood supply

1997 ◽  
Vol XXIX (3-4) ◽  
pp. 39-42
Author(s):  
A. A. Mikhailenko ◽  
М. М. Odinak ◽  
I. А. Voznjuk
Keyword(s):  
Blood Supply ◽  
Flow Speed ◽  
Cerebral Hemodynamics ◽  
Cerebrovascular Reactivity ◽  
Functional Tests ◽  
Diagnostic Significance ◽  
Ischemic Lesion ◽  
Cerebral Blood Supply ◽  
Speed Range ◽  
Early Manifestation

By methods of extra- and transcranial dopplerography, reoencephalography evaluation of correspodence of brain hemoperfusion and reserves of autoregulation during rest and functional tests in patients was carried out with early manifestations of insufficient blood supply of brain. For this purpose 114 patients with such disease and 70 healthy people were examined. The most diagnostic significance for revealing disorders of cerebral hemodynamics in people with early manifestations of ischemic lesion of brain, have alterations of values of linear blood flow speed, range of cerebrovascular reactivity, values of circulation resistance. They indicate adequacy of hemoperfusion, presence of stenosis and intracerebral overdistribution of circulating blood. Pathogenetic variants of insufficient cerebral blood supply are shown in the verterbrobasilar basin.

scholarly journals Visual perceptual learning of a primitive feature in human V1/V2 as a result of unconscious processing, revealed by Decoded fMRI Neurofeedback (DecNef)

2020 ◽  
Author(s):  
Zhiyan Wang ◽  
Masako Tamaki ◽  
Kazuhisa Shibata ◽  
Michael S. Worden ◽  
Takashi Yamada ◽  
...  
Keyword(s):  
Perceptual Learning ◽  
Activity Patterns ◽  
Neural Mechanism ◽  
Global Motion ◽  
Local Motion ◽  
Motion Direction ◽  
Visual Perceptual Learning ◽  
Visual Areas ◽  
Motion Display ◽  
Task Irrelevant

AbstractWhile numerous studies have shown that visual perceptual learning (VPL) occurs as a result of exposure to a visual feature in a task-irrelevant manner, the underlying neural mechanism is poorly understood. In a previous psychophysical study, subjects were repeatedly exposed to a task-irrelevant global motion display that induced the perception of not only the local motions but also a global motion moving in the direction of the spatiotemporal average of the local motion vectors. As a result, subjects enhanced their sensitivity only to the local moving directions, suggesting that early visual areas (V1/V2) that process local motions are involved in task-irrelevant VPL. However, this hypothesis has never been examined by directly examining the involvement of early visual areas (V1/V2). Here, we employed a decoded neurofeedback technique (DecNef) using functional magnetic resonance imaging. During the DecNef training, subjects were trained to induce the activity patterns in V1/V2 that were similar to those evoked by the actual presentation of the global motion display. The DecNef training was conducted with neither the actual presentation of the display nor the subjects’ awareness of the purpose of the experiment. As a result, subjects increased the sensitivity to the local motion directions but not specifically to the global motion direction. The training effect was strictly confined to V1/V2. Moreover, subjects reported that they neither perceived nor imagined any motion during the DecNef training. These results together suggest that that V1/V2 are sufficient for exposure-based task-irrelevant VPL to occur unconsciously.Significance StatementWhile numerous studies have shown that visual perceptual learning (VPL) occurs as a result of exposure to a visual feature in a task-irrelevant manner, the underlying neural mechanism is poorly understood. Previous psychophysical experiments suggest that early visual areas (V1/V2) are involved in task-irrelevant VPL. However, this hypothesis has never been examined by directly examining the involvement of early visual areas (V1/V2). Here, using decoded fMRI neurofeedback, the activity patterns similar to those evoked by the presentation of a complex motion display were repeatedly induced only in early visual areas. The training sensitized only the local motion directions and not the global motion direction, suggesting that V1/V2 are involved in task-irrelevant VPL.

scholarly journals Scrambling the skin: Simulated Skin Re-Arrangement Using Apparent Motion

2019 ◽  
Author(s):  
Tatjana Seizova-Cajic ◽  
Sandra Ludvigsson ◽  
Birger Sourander ◽  
Melinda Popov ◽  
Janet L Taylor
Keyword(s):  
Apparent Motion ◽  
Constant Velocity ◽  
Somatosensory System ◽  
Stimulus Onset ◽  
Object Motion ◽  
Local Motion ◽  
Motion Direction ◽  
Sensory Maps ◽  
Complete Reversal ◽  
Velocity Motion

I.ABSTRACTAn age-old hypothesis proposes that object motion across the receptor surface organizes sensory maps (Lotze, 19th century). Skin patches learn their relative positions from the order in which they are stimulated during motion events. We test this idea by reversing the local motion within a 6-point apparent motion sequence along the forearm. In the ‘Scrambled’ sequence, two middle locations were touched in reversed order (1-2-4-3-5-6, followed by 6-5-3-4-2-1, in a continuous loop). This created a local acceleration, a double U-turn, within an otherwise constant-velocity motion, as if the physical location of skin patches 3 and 4 was surgically swapped. The control condition, ‘Orderly’, proceeded at constant velocity at inter-stimulus onset interval (ISOI) of 120 ms. In the test, our twenty participants reported motion direction between the two middle tactors, presented on their own at 75, 120 or 190-ms ISOI. Results show degraded motion discrimination following exposure to Scrambled pattern: for the 120-ms test stimulus, it was 0.31 d’ weaker than following Orderly conditioning (p = .007). This is the aftereffect we expected; its maximal expression would be a complete reversal in perceived motion direction between locations 3 and 4 for either motion direction. We propose that the somatosensory system was beginning to ‘correct’ reversed local motion to uncurl and remove the U-turns that always occurred on the same part of the receptor surface. Such de-correlation between accelerations and their location on the sensory surface is one possible mechanism for organization of sensory maps.

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