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Vision Research Sep 2023Saccadic localisation of targets of various properties has been extensively studied, but rarely for texture-defined figures. In this paper, three experiments that...
Saccadic localisation of targets of various properties has been extensively studied, but rarely for texture-defined figures. In this paper, three experiments that investigate the way information from a texture target is processed in order to provide a signal for eye movement control are presented. Participants made saccades to target regions embedded in a background structure, and the saccade landing position and latency were measured. The textures comprised line elements, with orientations of the lines configured to form the figure and ground. Various orientation profile configurations (Block, Blur, and Cornsweet), were used in order to measure the role of edge profiles in driving eye movements and producing salience. We found that in all cases the visual system is in fact able to effectively segregate a texture figure from the ground in order to accurately plan a saccade to the target-figure. While saccadic latency was the highest for the Blur profile, the mean saccadic landing position was mostly unaffected by the various profiles (Experiment 1). More specifically, we showed that saccades were directed to the centre-of-gravity of the target (Experiment 2). We also found that figures with information of orientation contrast at both the edge and centre of figure (i.e. Block) produced the highest level of saliency in attracting eye movements (Experiment 3). Overall, the results show that saccades are planned on the representation of the whole target shape rather than a local salient region based on orientation contrast cues, and that the various texture profiles were important only to the extent that they affected the time to programme a saccade.
Topics: Humans; Eye Movements; Saccades; Reaction Time
PubMed: 37276684
DOI: 10.1016/j.visres.2023.108264 -
Journal of Vision Apr 2018Does visual processing start anew after each eye movement, or is information integrated across saccades? Here we test a strong prediction of the integration hypothesis:...
Does visual processing start anew after each eye movement, or is information integrated across saccades? Here we test a strong prediction of the integration hypothesis: that information acquired after a saccade interferes with the perception of images acquired before the saccade. We investigate perception of a basic visual feature, grating orientation, and we take advantage of a delayed interference phenomenon-in human participants, the reported orientation of a target grating, briefly presented at an eccentric location, is strongly biased toward the orientation of flanker gratings that are flashed shortly after the target. Crucially, we find that the effect is the same whether or not a saccade is made during the delay interval even though the eye movement produces a large retinotopic separation between target and flankers. However, the trans-saccadic effect nearly vanishes when flankers are displaced to a different screen location even when this location matches the retinotopic coordinates of the target. We conclude that information about grating orientation is integrated across saccades within a spatial region that is defined in external coordinates and thereby is stable in spite of the movement of the eyes.
Topics: Adult; Female; Humans; Male; Orientation; Saccades; Visual Perception; Young Adult
PubMed: 29621386
DOI: 10.1167/18.4.9 -
Vision Research Apr 2006Saccades are necessary for optimal vision. Little is known about saccades in children. We recorded saccades using an infrared eye tracker in 39 children, aged 8-19...
Saccades are necessary for optimal vision. Little is known about saccades in children. We recorded saccades using an infrared eye tracker in 39 children, aged 8-19 years. Participants made saccades to visual targets that stepped 10 degrees or 15 degrees horizontally and 5 degrees or 10 degrees vertically at unpredictable time intervals. Saccadic latency decreased significantly with increasing age, while saccadic gain and peak velocity did not vary with age. Saccadic gains and peak velocities in children are similar to reported adult values. This implies maturity of the neural circuits responsible for making saccades accurate and fast. Saccade latency decreases as the brain matures.
Topics: Adolescent; Adult; Child; Female; Humans; Infrared Rays; Male; Reproducibility of Results; Saccades; Video Recording; Visual Perception
PubMed: 16051306
DOI: 10.1016/j.visres.2005.06.011 -
Experimental Eye Research Sep 2013The rapid point-to-point movements of the eyes called saccades are the most commonly made movement by humans, yet differ from nearly every other type of motor output in... (Review)
Review
The rapid point-to-point movements of the eyes called saccades are the most commonly made movement by humans, yet differ from nearly every other type of motor output in that they are completed too quickly to be adjusted during their execution by visual feedback. Saccadic accuracy remains quite high over a lifetime despite inevitable changes to the physical structures controlling the eyes, indicating that the oculomotor system actively monitors and adjusts motor commands to achieve consistent behavioral production. Indeed, it seems that beyond the ability to compensate for slow, age-related bodily changes, saccades can be modified following traumatic injury or pathology that affects their production, or in response to more short-term systematic alterations to post-saccadic visual feedback in a laboratory setting. These forms of plasticity rely on the visual detection of accuracy errors by a unified set of mechanisms that support the process known as saccade adaptation. Saccade adaptation has been mostly studied as a phenomenon in its own right, outside of motor learning in general. Here, we highlight the commonalities between eye and arm movement adaptation by reviewing the literature across these fields wherever there are compelling overlapping theories or data. Recent exciting findings are challenging previous interpretations of the underlying mechanisms of saccade adaptation with the incorporation of concepts including prediction, reinforcement and contextual learning. We review the emerging ideas and evidence with particular emphasis on the important contributions made by Josh Wallman in this sphere over the past 15 years.
Topics: Adaptation, Ocular; Feedback, Sensory; Humans; Learning; Psychomotor Performance; Saccades
PubMed: 23597598
DOI: 10.1016/j.exer.2013.04.001 -
Vision Research Aug 2010Our actions need constant calibration to arrive accurately at locations of their intended goals; errors in execution must drive rapid adjustments. As an example,...
Our actions need constant calibration to arrive accurately at locations of their intended goals; errors in execution must drive rapid adjustments. As an example, saccadic eye movements are vital for bringing objects of interest into the high-acuity center of vision and they must be continually tuned to compensate for ongoing changes in body, muscle strength and neural variability. This adaptation of eye movement responses can be induced artificially by systematically displacing the saccade targets by a constant proportion during each saccade. Observers do not notice these shifts and yet the oculomotor system does, rapidly compensating for the landing error until the saccades finally land close to the artificially displaced target. This recalibration has been described as spatially selective, dropping off with distance in direction and amplitude from the adapted saccade vector. However, we now report that this local adaptation property is a consequence of adapting to only one direction at a time, the method generally used in previous studies. When we induced adaptation in all directions, using a quasi-random walk where each target was displaced 25% back toward to the previous fixation, we found strong, spatially generalized adaptation that could not be accounted for by an accumulation of many vector-specific adaptations. This global adaptation is a plausible strategy for calibration given the absence of any obvious growth changes or muscle deficits that would lead to vector specific losses and it provides a robust model for testing motor calibration.
Topics: Adaptation, Ocular; Adult; Eye Movements; Female; Humans; Male; Photic Stimulation; Saccades; Visual Fields; Visual Perception; Young Adult
PubMed: 20600235
DOI: 10.1016/j.visres.2010.06.010 -
PloS One 2019Saccadic adaptation is assumed to be driven by an unconscious and automatic mechanism. We wondered if the adaptation process is accessible to volitional control,...
Saccadic adaptation is assumed to be driven by an unconscious and automatic mechanism. We wondered if the adaptation process is accessible to volitional control, specifically whether any change in saccade gain can be inhibited. Participants were exposed to post-saccadic error by using the double-step paradigm in which a target is presented in a peripheral location and then stepped during the saccade to another location. In one condition, participants were instructed to follow the target step and look at the final target location. In the other condition they were instructed to inhibit the adjustment of saccade amplitude and look at the initial target location. We conducted two experiments, which differed in the size of the intra-saccadic target step. We found that when told to inhibit amplitude adjustment, gain change was close to zero for outward steps, but some adaptation remained for inward steps. Saccadic latency was not affected by the instruction type for inward steps, but when the target was stepped outward, latencies were longer in the inhibition than in the adaptation condition. The results show that volitional control can be exerted on saccadic adaptation. We suggest that volitional control affects the remapping of the target, thus having a larger impact on outward adaptation.
Topics: Adaptation, Physiological; Adolescent; Adult; Female; Humans; Male; Middle Aged; Photic Stimulation; Reaction Time; Saccades; Volition; Young Adult
PubMed: 30629610
DOI: 10.1371/journal.pone.0210020 -
Experimental Brain Research Feb 2015Visual objects briefly presented around the time of saccadic eye movements are perceived compressed towards the saccade target. Here, we investigated perisaccadic...
Visual objects briefly presented around the time of saccadic eye movements are perceived compressed towards the saccade target. Here, we investigated perisaccadic mislocalization with a double-step saccade paradigm, measuring localization of small probe dots briefly flashed at various times around the sequence of the two saccades. At onset of the first saccade, probe dots were mislocalized towards the first and, to a lesser extent, also towards the second saccade target. However, there was very little mislocalization at the onset of the second saccade. When we increased the presentation duration of the saccade targets prior to onset of the saccade sequence, perisaccadic mislocalization did occur at the onset of the second saccade.
Topics: Adult; Analysis of Variance; Female; Humans; Male; Orientation; Perceptual Distortion; Photic Stimulation; Saccades; Space Perception; Time Factors
PubMed: 25370348
DOI: 10.1007/s00221-014-4138-z -
Attention, Perception & Psychophysics Oct 2015Saccadic remapping, a presaccadic increase in neural activity when a saccade is about to bring an object into a neuron's receptive field, may be crucial for our...
Saccadic remapping, a presaccadic increase in neural activity when a saccade is about to bring an object into a neuron's receptive field, may be crucial for our perception of a stable world. Studies of perception and saccadic remapping, like ours, focus on the presaccadic acquisition of information from the saccade target, with no direct reference to underlying physiology. While information is known to be acquired prior to a saccade, it is unclear whether object-selective or feature-specific information is remapped. To test this, we performed a series of psychophysical experiments in which we presented a peripheral, nonfoveated face as a presaccadic target. The target face disappeared at saccade onset. After making a saccade to the location of the peripheral target face (which was no longer visible), subjects misperceived the expression of a subsequent, foveally presented neutral face as being repelled away from the peripheral presaccadic face target. This effect was similar to a sequential shape contrast or negative aftereffect but required a saccade, because covert attention was not sufficient to generate the illusion. Additional experiments further revealed that inverting the faces disrupted the illusion, suggesting that presaccadic remapping is object-selective and not based on low-level features. Our results demonstrate that saccadic remapping can be an object-selective process, spatially tuned to the target of the saccade and distinct from covert attention in the absence of a saccade.
Topics: Attention; Humans; Illusions; Photic Stimulation; Psychophysics; Saccades; Visual Perception
PubMed: 26069198
DOI: 10.3758/s13414-015-0944-z -
Philosophical Transactions of the Royal... Feb 2011In the present review, we address the relationship between attention and visual stability. Even though with each eye, head and body movement the retinal image changes... (Review)
Review
In the present review, we address the relationship between attention and visual stability. Even though with each eye, head and body movement the retinal image changes dramatically, we perceive the world as stable and are able to perform visually guided actions. However, visual stability is not as complete as introspection would lead us to believe. We attend to only a few items at a time and stability is maintained only for those items. There appear to be two distinct mechanisms underlying visual stability. The first is a passive mechanism: the visual system assumes the world to be stable, unless there is a clear discrepancy between the pre- and post-saccadic image of the region surrounding the saccade target. This is related to the pre-saccadic shift of attention, which allows for an accurate preview of the saccade target. The second is an active mechanism: information about attended objects is remapped within retinotopic maps to compensate for eye movements. The locus of attention itself, which is also characterized by localized retinotopic activity, is remapped as well. We conclude that visual attention is crucial in our perception of a stable world.
Topics: Attention; Brain Mapping; Humans; Saccades; Vision, Ocular; Visual Pathways; Visual Perception
PubMed: 21242140
DOI: 10.1098/rstb.2010.0187 -
Journal of Vision Jul 2023We actively seek information from the environment through saccadic eye movements, necessitating continual integration of presaccadic and postsaccadic signals, which are...
We actively seek information from the environment through saccadic eye movements, necessitating continual integration of presaccadic and postsaccadic signals, which are displaced on the retina by each saccade. We tested whether trans-saccadic integration may be related to serial dependence (a measure of how perceptual history influences current perception) by measuring how viewing a presaccadic stimulus affects the perceived orientation of a subsequent test stimulus presented around the time of a saccade. Participants reproduced the position, and orientation of a test stimulus presented around a 16° saccade. The reproduced position was mislocalized toward the saccadic target, agreeing with previous work. The reproduced orientation was attracted toward the prior stimulus and regressed to the mean orientation. These results suggest that both short- and long-term past information affects trans-saccadic perception, most strongly when the test stimulus is presented perisaccadically. This study unites the fields of serial dependence and trans-saccadic perception, leading to potential new insights of how information is transferred and accumulated across saccades.
Topics: Humans; Saccades; Judgment; Photic Stimulation; Retina
PubMed: 37428485
DOI: 10.1167/jov.23.7.7