scholarly journals Sequential Nonlinear Filtering of Local Motion Cues by Global Motion Circuits

Neuron ◽  
2018 ◽  
Vol 100 (1) ◽  
pp. 229-243.e3 ◽  
Author(s):  
Erin L. Barnhart ◽  
Irving E. Wang ◽  
Huayi Wei ◽  
Claude Desplan ◽  
Thomas R. Clandinin
Keyword(s):  
Nonlinear Filtering ◽  
Global Motion ◽  
Local Motion ◽  
Motion Cues

Improving motion detection via anodal transcranial direct current stimulation

2020 ◽  
Vol 38 (5) ◽  
pp. 395-405
Author(s):  
Luca Battaglini ◽  
Federica Mena ◽  
Clara Casco
Keyword(s):  
Direct Current ◽  
Signal To Noise Ratio ◽  
Individual Performance ◽  
Coherent Motion ◽  
Motion Processing ◽  
Global Motion ◽  
Local Motion ◽  
Processing Efficiency ◽  
Temporal Area ◽  
Direct Current Stimulation

Background: To study motion perception, a stimulus consisting of a field of small, moving dots is often used. Generally, some of the dots coherently move in the same direction (signal) while the rest move randomly (noise). A percept of global coherent motion (CM) results when many different local motion signals are combined. CM computation is a complex process that requires the integrity of the middle-temporal area (MT/V5) and there is evidence that increasing the number of dots presented in the stimulus makes such computation more efficient. Objective: In this study, we explored whether anodal direct current stimulation (tDCS) over MT/V5 would increase individual performance in a CM task at a low signal-to-noise ratio (SNR, i.e. low percentage of coherent dots) and with a target consisting of a large number of moving dots (high dot numerosity, e.g. >250 dots) with respect to low dot numerosity (<60 dots), indicating that tDCS favour the integration of local motion signal into a single global percept (global motion). Method: Participants were asked to perform a CM detection task (two-interval forced-choice, 2IFC) while they received anodal, cathodal, or sham stimulation on three different days. Results: Our findings showed no effect of cathodal tDCS with respect to the sham condition. Instead, anodal tDCS improves performance, but mostly when dot numerosity is high (>400 dots) to promote efficient global motion processing. Conclusions: The present study suggests that tDCS may be used under appropriate stimulus conditions (low SNR and high dot numerosity) to boost the global motion processing efficiency, and may be useful to empower clinical protocols to treat visual deficits.

Self-supervised Motion Representation via Scattering Local Motion Cues

2020 ◽  
pp. 71-89
Author(s):  
Yuan Tian ◽  
Zhaohui Che ◽  
Wenbo Bao ◽  
Guangtao Zhai ◽  
Zhiyong Gao
Keyword(s):  
Local Motion ◽  
Motion Representation ◽  
Motion Cues

scholarly journals Spatial selectivity of local motion affects global motion after-effect

2010 ◽  
Vol 6 (6) ◽  
pp. 1048-1048
Author(s):  
Y. Nakajima ◽  
T. Sato
Keyword(s):  
Global Motion ◽  
Local Motion ◽  
Spatial Selectivity ◽  
After Effect

scholarly journals Top-down Influence of Global Motion Patterns on Local Motion Patterns

2019 ◽  
Vol 19 (10) ◽  
pp. 165a
Author(s):  
Darwin Romulus ◽  
Sang W Hong ◽  
Howard Hock
Keyword(s):  
Global Motion ◽  
Local Motion ◽  
Top Down ◽  
Motion Patterns

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.

An fMRI study of cortical activation during left-right discrimination of static, local motion, global motion and biological motion stimuli

NeuroImage ◽  
2000 ◽  
Vol 11 (5) ◽  
pp. S702 ◽  
Author(s):  
K.D. Singh ◽  
A.L. Williams ◽  
A.T. Smith
Keyword(s):  
Biological Motion ◽  
Cortical Activation ◽  
Global Motion ◽  
Local Motion ◽  
Fmri Study

scholarly journals The tactile integration of local motion cues is analogous to its visual counterpart

2008 ◽  
Vol 105 (23) ◽  
pp. 8130-8135 ◽  
Author(s):  
Y. C. Pei ◽  
S. S. Hsiao ◽  
S. J. Bensmaia
Keyword(s):  
Local Motion ◽  
Motion Cues ◽  
Tactile Integration
Sign in / Sign up

Export Citation Format

Share Document