scholarly journals Visual sensitivity and bias oscillate phase-locked to saccadic eye movements

2019 ◽  
Vol 19 (14) ◽  
pp. 15 ◽  
Author(s):  
Alessandro Benedetto ◽  
Maria Concetta Morrone
Keyword(s):  
Eye Movements ◽  
Saccadic Eye Movements ◽  
Visual Sensitivity

scholarly journals Contrast sensitivity, V1 neural activity, and natural vision

2017 ◽  
Vol 117 (2) ◽  
pp. 492-508 ◽  
Author(s):  
James E. Niemeyer ◽  
Michael A. Paradiso
Keyword(s):  
Eye Movements ◽  
Contrast Sensitivity ◽  
Visual Processing ◽  
Brain Area ◽  
Saccadic Eye Movements ◽  
Visual Sensitivity ◽  
Natural Image ◽  
Spatial Frequencies ◽  
Natural Vision ◽  
Common Laboratory

Contrast sensitivity is fundamental to natural visual processing and an important tool for characterizing both visual function and clinical disorders. We simultaneously measured contrast sensitivity and neural contrast response functions and compared measurements in common laboratory conditions with naturalistic conditions. In typical experiments, a subject holds fixation and a stimulus is flashed on, whereas in natural vision, saccades bring stimuli into view. Motivated by our previous V1 findings, we tested the hypothesis that perceptual contrast sensitivity is lower in natural vision and that this effect is associated with corresponding changes in V1 activity. We found that contrast sensitivity and V1 activity are correlated and that the relationship is similar in laboratory and naturalistic paradigms. However, in the more natural situation, contrast sensitivity is reduced up to 25% compared with that in a standard fixation paradigm, particularly at lower spatial frequencies, and this effect correlates with significant reductions in V1 responses. Our data suggest that these reductions in natural vision result from fast adaptation on one fixation that lowers the response on a subsequent fixation. This is the first demonstration of rapid, natural-image adaptation that carries across saccades, a process that appears to constantly influence visual sensitivity in natural vision. NEW & NOTEWORTHY Visual sensitivity and activity in brain area V1 were studied in a paradigm that included saccadic eye movements and natural visual input. V1 responses and contrast sensitivity were significantly reduced compared with results in common laboratory paradigms. The parallel neural and perceptual effects of eye movements and stimulus complexity appear to be due to a form of rapid adaptation that carries across saccades.

scholarly journals Suppression without inhibition: A novel mechanism in the retina accounts for saccadic suppression

2020 ◽  
Author(s):  
Saad Idrees ◽  
Matthias-Philipp Baumann ◽  
Maria M. Korympidou ◽  
Timm Schubert ◽  
Alexandra Kling ◽  
...  
Keyword(s):  
Eye Movements ◽  
Visual Perception ◽  
Receptive Field ◽  
Calcium Imaging ◽  
Ganglion Cells ◽  
Saccadic Eye Movements ◽  
Visual Sensitivity ◽  
Saccadic Suppression ◽  
Retinal Processing ◽  
Retinal Pathways

AbstractVisual perception remains stable across saccadic eye movements, despite the concurrent strongly disruptive visual flow. This stability is partially associated with a reduction in visual sensitivity, known as saccadic suppression, which already starts in the retina with reduced ganglion cell sensitivity. However, the retinal circuit mechanisms giving rise to such suppression remain unknown. Here, we describe these mechanisms using electrophysiology in mouse, pig, and macaque retina, 2-photon calcium imaging, computational modeling, and human psychophysics. We find a novel retinal processing motif underlying retinal saccadic suppression, “dynamic reversal suppression”, which is triggered by sequential stimuli containing contrast reversals. This motif does not involve inhibition but relies on nonlinear transformation of the inherently slow responses of cone photoreceptors by downstream retinal pathways. Two further components of suppression are present in ON ganglion cells and originate in the cells’ receptive field surround, highlighting a novel disparity between ON and OFF ganglion cells. Our results are relevant for any sequential stimulation encountered frequently in naturalistic scenarios.

scholarly journals Saccadic suppression measured by steady-state visual evoked potentials

2019 ◽  
Vol 122 (1) ◽  
pp. 251-258 ◽  
Author(s):  
Jing Chen ◽  
Matteo Valsecchi ◽  
Karl R. Gegenfurtner
Keyword(s):  
Steady State ◽  
Eye Movements ◽  
Evoked Potentials ◽  
Neural Activity ◽  
Temporal Dynamics ◽  
Visual Stimulation ◽  
Saccadic Eye Movements ◽  
Visual Sensitivity ◽  
Saccadic Suppression ◽  
Saccade Onset

Visual sensitivity is severely impaired during the execution of saccadic eye movements. This phenomenon has been extensively characterized in human psychophysics and nonhuman primate single-neuron studies, but a physiological characterization in humans is less established. Here, we used a method based on steady-state visually evoked potential (SSVEP), an oscillatory brain response to periodic visual stimulation, to examine how saccades affect visual sensitivity. Observers made horizontal saccades back and forth, while horizontal black-and-white gratings flickered at 5–30 Hz in the background. We analyzed EEG epochs with a length of 0.3 s either centered at saccade onset (saccade epochs) or centered at fixations half a second before the saccade (fixation epochs). Compared with fixation epochs, saccade epochs showed a broadband power increase, which most likely resulted from saccade-related EEG activity. The execution of saccades, however, led to an average reduction of 57% in the SSVEP amplitude at the stimulation frequency. This result provides additional evidence for an active saccadic suppression in the early visual cortex in humans. Compared with previous functional MRI and EEG studies, an advantage of this approach lies in its capability to trace the temporal dynamics of neural activity throughout the time course of a saccade. In contrast to previous electrophysiological studies in nonhuman primates, we did not find any evidence for postsaccadic enhancement, even though simulation results show that our method would have been able to detect it. We conclude that SSVEP is a useful technique to investigate the neural correlates of visual perception during saccadic eye movements in humans. NEW & NOTEWORTHY We make fast ballistic saccadic eye movements a few times every second. At the time of saccades, visual sensitivity is severely impaired. The present study uses steady-state visually evoked potentials to reveal a neural correlate of the fine temporal dynamics of these modulations at the time of saccades in humans. We observed a strong reduction (57%) of visually driven neural activity associated with saccades but did not find any evidence for postsaccadic enhancement.

scholarly journals Visual sensitivity of frontal eye field neurons during the preparation of saccadic eye movements

2016 ◽  
Vol 116 (6) ◽  
pp. 2882-2891 ◽  
Author(s):  
Rebecca M. Krock ◽  
Tirin Moore
Keyword(s):  
Visual Cortex ◽  
Eye Movements ◽  
Saccadic Eye Movements ◽  
Visual Sensitivity ◽  
Saccadic Suppression ◽  
Frontal Eye Field ◽  
Visually Guided ◽  
Visual Neurons ◽  
Saccade Onset ◽  
Eye Field

Primate vision is continuously disrupted by saccadic eye movements, and yet this disruption goes unperceived. One mechanism thought to reduce perception of this self-generated movement is saccadic suppression, a global loss of visual sensitivity just before, during, and after saccadic eye movements. The frontal eye field (FEF) is a candidate source of neural correlates of saccadic suppression previously observed in visual cortex, because it contributes to the generation of visually guided saccades and modulates visual cortical responses. However, whether the FEF exhibits a perisaccadic reduction in visual sensitivity that could be transmitted to visual cortex is unknown. To determine whether the FEF exhibits a signature of saccadic suppression, we recorded the visual responses of FEF neurons to brief, full-field visual probe stimuli presented during fixation and before onset of saccades directed away from the receptive field in rhesus macaques ( Macaca mulatta). We measured visual sensitivity during both epochs and found that it declines before saccade onset. Visual sensitivity was significantly reduced in visual but not visuomotor neurons. This reduced sensitivity was also present in visual neurons with no movement-related modulation during visually guided saccades and thus occurred independently from movement-related activity. Across the population of visual neurons, sensitivity began declining ∼80 ms before saccade onset. We also observed a similar presaccadic reduction in sensitivity to isoluminant, chromatic stimuli. Our results demonstrate that the signaling of visual information by FEF neurons is reduced during saccade preparation, and thus these neurons exhibit a signature of saccadic suppression.

The effect of task set on fixational saccadic eye movements

2013 ◽  
Author(s):  
Sara Spotorno ◽  
Guillaume S. Masson ◽  
Anna Montagnini
Keyword(s):  
Eye Movements ◽  
Saccadic Eye Movements ◽  
Task Set
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