scholarly journals Perceived direction of deformation flow

2019 ◽  
Author(s):  
Takahiro Kawabe
Keyword(s):  
Discrimination Performance ◽  
Natural World ◽  
Natural Image ◽  
Global Motion ◽  
Motion Direction ◽  
Image Deformation ◽  
Direction Discrimination ◽  
Transparent Liquid ◽  
Shearing Deformation ◽  
Opposite Motion

AbstractIn everyday circumstances, human observers can easily discriminate the direction of transparent liquid flow. However, the mechanism of direction discrimination is not so straightforward. The present study focused on the flow of image deformation, which is closely related to the flow of transparent liquid in the natural world. To determine what image information is important in discriminating the direction of deformation flow, a natural image in a stimulus clip was deformed by using a deformation vector map that translated leftward or rightward. The task of the observers was to judge whether the transparent liquid in the clip flowed leftward or rightward. Manipulating the amplitude of deformation, we found that the discrimination performance improved with the amplitude. Interestingly, the observers’ performance was high overall only when shearing deformation was applied to the stimuli, while the observers reported an opposite-motion direction when only compressive deformation was applied. We computationally analyzed motion statistics of stimuli and found that the combination of mean and skewness of horizontal motion vectors reliably predicted the performance. The results indicate that human observers use global motion directions in order to determine the direction of deformation flow.

scholarly journals Global motion perception is independent from contrast sensitivity for coherent motion direction discrimination and visual acuity in 4.5-year-old children

2015 ◽  
Vol 115 ◽  
pp. 83-91 ◽  
Author(s):  
Arijit Chakraborty ◽  
Nicola S. Anstice ◽  
Robert J. Jacobs ◽  
Nabin Paudel ◽  
Linda L. LaGasse ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Contrast Sensitivity ◽  
Motion Perception ◽  
Coherent Motion ◽  
Global Motion ◽  
Motion Direction ◽  
Direction Discrimination

scholarly journals Motion Direction Discrimination with Tactile Random-Dot Kinematograms

i-Perception ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 204166952110046
Author(s):  
Scinob Kuroki ◽  
Shin’ya Nishida
Keyword(s):  
Motion Detection ◽  
Visual Motion ◽  
Discrimination Performance ◽  
Sensory Function ◽  
Human Observer ◽  
Motion Sensing ◽  
Motion Direction ◽  
Low Level ◽  
Direction Discrimination ◽  
High Level

Motion detection is a fundamental sensory function for multiple modalities, including touch, but the mechanisms underlying tactile motion detection are not well understood. While previous findings supported the existence of high-level feature tracking, it remains unclear whether there also exist low-level motion sensing that directly detects a local spatio-temporal correlation in the skin-stimulation pattern. To elucidate this mechanism, we presented, on braille displays, tactile random-dot kinematograms, similar to those widely used in visual motion research, which enables us to independently manipulate feature trackability and various parameters of local motion. We found that a human observer is able to detect the direction of difficult-to-track tactile motions presented to the fingers and palms. In addition, the direction-discrimination performance was better when the stimuli were presented along the fingers than when presented across the fingers. These results indicate that low-level motion sensing, in addition to high-level tracking, contribute to tactile motion perception.

scholarly journals Diminished Parietal Cortex Activity Associated with Poor Motion Direction Discrimination Performance in Schizophrenia

2009 ◽  
Vol 20 (7) ◽  
pp. 1749-1755 ◽  
Author(s):  
J. Wang ◽  
R. Brown ◽  
K. R. Dobkins ◽  
J. E. McDowell ◽  
B. A. Clementz
Keyword(s):  
Parietal Cortex ◽  
Discrimination Performance ◽  
Motion Direction ◽  
Direction Discrimination

scholarly journals Electrophysiological aftereffects of high-frequency transcranial random noise stimulation (hf-tRNS): an EEG investigation

2021 ◽  
Author(s):  
Filippo Ghin ◽  
Louise O’Hare ◽  
Andrea Pavan
Keyword(s):  
High Frequency ◽  
Discrimination Task ◽  
Temporal Dynamics ◽  
Random Noise ◽  
Decomposition Analysis ◽  
Oscillatory Activity ◽  
Motion Direction ◽  
Time Frequency ◽  
Direction Discrimination ◽  
Transcranial Random Noise Stimulation

AbstractThere is evidence that high-frequency transcranial random noise stimulation (hf-tRNS) is effective in improving behavioural performance in several visual tasks. However, so far there has been limited research into the spatial and temporal characteristics of hf-tRNS-induced facilitatory effects. In the present study, electroencephalogram (EEG) was used to investigate the spatial and temporal dynamics of cortical activity modulated by offline hf-tRNS on performance on a motion direction discrimination task. We used EEG to measure the amplitude of motion-related VEPs over the parieto-occipital cortex, as well as oscillatory power spectral density (PSD) at rest. A time–frequency decomposition analysis was also performed to investigate the shift in event-related spectral perturbation (ERSP) in response to the motion stimuli between the pre- and post-stimulation period. The results showed that the accuracy of the motion direction discrimination task was not modulated by offline hf-tRNS. Although the motion task was able to elicit motion-dependent VEP components (P1, N2, and P2), none of them showed any significant change between pre- and post-stimulation. We also found a time-dependent increase of the PSD in alpha and beta bands regardless of the stimulation protocol. Finally, time–frequency analysis showed a modulation of ERSP power in the hf-tRNS condition for gamma activity when compared to pre-stimulation periods and Sham stimulation. Overall, these results show that offline hf-tRNS may induce moderate aftereffects in brain oscillatory activity.

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.

Human Updating of Visual Motion Direction During Head Rotations

2008 ◽  
Vol 99 (5) ◽  
pp. 2558-2576
Author(s):  
Mario Ruiz-Ruiz ◽  
Julio C. Martinez-Trujillo
Keyword(s):  
Visual Motion ◽  
Human Subjects ◽  
Head Tilt ◽  
Head Rotation ◽  
Three Dimensions ◽  
Spatial Updating ◽  
Motion Direction ◽  
Direction Discrimination ◽  
Head Rotations ◽  
Stimulus Direction

Previous studies have demonstrated that human subjects update the location of visual targets for saccades after head and body movements and in the absence of visual feedback. This phenomenon is known as spatial updating. Here we investigated whether a similar mechanism exists for the perception of motion direction. We recorded eye positions in three dimensions and behavioral responses in seven subjects during a motion task in two different conditions: when the subject's head remained stationary and when subjects rotated their heads around an anteroposterior axis (head tilt). We demonstrated that after head-tilt subjects updated the direction of saccades made in the perceived stimulus direction (direction of motion updating), the amount of updating varied across subjects and stimulus directions, the amount of motion direction updating was highly correlated with the amount of spatial updating during a memory-guided saccade task, subjects updated the stimulus direction during a two-alternative forced-choice direction discrimination task in the absence of saccadic eye movements (perceptual updating), perceptual updating was more accurate than motion direction updating involving saccades, and subjects updated motion direction similarly during active and passive head rotation. These results demonstrate the existence of an updating mechanism for the perception of motion direction in the human brain that operates during active and passive head rotations and that resembles the one of spatial updating. Such a mechanism operates during different tasks involving different motor and perceptual skills (saccade and motion direction discrimination) with different degrees of accuracy.

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.

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