scholarly journals Global motion processing by populations of direction-selective retinal ganglion cells

2019 ◽  
Author(s):  
Jon Cafaro ◽  
Joel Zylberberg ◽  
Greg Field
Keyword(s):  
Ganglion Cells ◽  
Neural Population ◽  
Mouse Retina ◽  
Motion Processing ◽  
High Temporal Resolution ◽  
Retinal Ganglion ◽  
Global Motion ◽  
Local Motion ◽  
Motion Direction ◽  
Temporal Precision

AbstractSimple stimuli have been critical to understanding neural population codes in sensory systems. Yet it remains necessary to determine the extent to which this understanding generalizes to more complex conditions. To explore this problem, we measured how populations of direction-selective ganglion cells (DSGCs) from mouse retina respond to a global motion stimulus with its direction and speed changing dynamically. We then examined the encoding and decoding of motion direction in both individual and populations of DSGCs. Individual cells integrated global motion over ~200 ms, and responses were tuned to direction. However, responses were sparse and broadly tuned, which severely limited decoding performance from small DSGC populations. In contrast, larger populations compensated for response sparsity, enabling decoding with high temporal precision (<100 ms). At these timescales, correlated spiking was minimal and had little impact on decoding performance, unlike results obtained using simpler local motion stimuli decoded over longer timescales. We use these data to define different DSGC population decoding regimes that utilize or mitigate correlated spiking to achieve high spatial versus high temporal resolution.

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 Center-surround interactions underlie bipolar cell motion sensing in the mouse retina

2021 ◽  
Author(s):  
Sarah Strauss ◽  
Maria M Korympidou ◽  
Yanli Ran ◽  
Katrin Franke ◽  
Timm Schubert ◽  
...  
Keyword(s):  
Bipolar Cell ◽  
Ganglion Cells ◽  
Receptive Fields ◽  
Amacrine Cells ◽  
Bipolar Cells ◽  
Mouse Retina ◽  
Motion Processing ◽  
Local Motion ◽  
Motion Sensing ◽  
Motion Sensitivity

Motion is a critical aspect of vision. We studied the representation of motion in mouse retinal bipolar cells and found, surprisingly, that some bipolar cells possess motion-sensing capabilities that rely on their center-surround receptive fields. Using a glutamate sensor, we directly observed motion-sensitive bipolar cell synaptic output, which was strongest for local motion and dependent on the motion's origin. We characterized bipolar cell receptive fields and found that there are motion and non-motion sensitive bipolar cell types, the majority being motion sensitive. Next, we used these bipolar cell receptive fields along with connectomics to design biophysical models of downstream cells. The models and experiments demonstrated that bipolar cells pass motion-sensitive excitation to starburst amacrine cells through direction-specific signals mediated by bipolar cells' center-surround receptive field structure. As bipolar cells provide excitation to most amacrine and ganglion cells, their motion sensitivity may contribute to motion processing throughout the visual system.

scholarly journals Conserved Circuits for Direction Selectivity in the Primate Retina

2021 ◽  
Author(s):  
Sara S Patterson ◽  
Briyana N Bembry ◽  
Marcus A Mazzaferri ◽  
Maureen Neitz ◽  
Fred Rieke ◽  
...  
Keyword(s):  
Ganglion Cells ◽  
Selective Inhibition ◽  
Direction Selectivity ◽  
Structural Basis ◽  
Motion Processing ◽  
Retinal Ganglion ◽  
Accessory Optic System ◽  
Motion Direction ◽  
Open Question ◽  
Starburst Amacrine Cell

The detection of motion direction is a fundamental visual function and a classic model for neural computation. In the non-primate mammalian retina, direction selectivity arises in starburst amacrine cell (SAC) dendrites, which provide selective inhibition to ON and ON-OFF direction selective retinal ganglion cells (dsRGCs). While SACs are present in primates, their connectivity is unknown and the existence of primate dsRGCs remains an open question. Here we present a connectomic reconstruction of the primate ON SAC circuit from a serial electron microscopy volume of macaque central retina. We show that the structural basis for the SAC's ability to compute and confer directional selectivity on post-synaptic RGCs is conserved in primates and that SACs selectively target a single ganglion cell type, a candidate homolog to the mammalian ON-sustained dsRGCs that project to the accessory optic system and contribute to gaze-stabilizing reflexes. These results indicate that the capacity to compute motion direction is present in the retina, far earlier in the primate visual system than classically thought, and they shed light on the distinguishing features of primate motion processing by revealing the extent to which ancestral motion circuits are conserved.

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.

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 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 The movement of motion-defined contours can bias perceived position

2009 ◽  
Vol 5 (2) ◽  
pp. 270-273 ◽  
Author(s):  
Szonya Durant ◽  
Johannes M Zanker
Keyword(s):  
Visual Processing ◽  
Spatial Location ◽  
Motion Processing ◽  
Local Motion ◽  
Motion Direction ◽  
Motion Patterns ◽  
Object Properties ◽  
Accurate Position ◽  
Processing Steps ◽  
Over Time

Illusory position shifts induced by motion suggest that motion processing can interfere with perceived position. This may be because accurate position representation is lost during successive visual processing steps. We found that complex motion patterns, which can only be extracted at a global level by pooling and segmenting local motion signals and integrating over time, can influence perceived position. We used motion-defined Gabor patterns containing motion-defined boundaries, which themselves moved over time. This ‘motion-defined motion’ induced position biases of up to 0.5°, much larger than has been found with luminance-defined motion. The size of the shift correlated with how detectable the motion-defined motion direction was, suggesting that the amount of bias increased with the magnitude of this complex directional signal. However, positional shifts did occur even when participants were not aware of the direction of the motion-defined motion. The size of the perceptual position shift was greatly reduced when the position judgement was made relative to the location of a static luminance-defined square, but not eliminated. These results suggest that motion-induced position shifts are a result of general mechanisms matching dynamic object properties with spatial location.

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