scholarly journals Unrestricted eye movements strengthen causal connectivity from hippocampal to oculomotor regions during scene construction

2021 ◽  
Author(s):  
Natalia Ladyka-Wojcik ◽  
Zhong-Xu Liu ◽  
Jennifer D. Ryan
Keyword(s):  
Eye Movements ◽  
Visual Processing ◽  
Oculomotor System ◽  
Visual Input ◽  
Causal Modeling ◽  
Oculomotor Control ◽  
Visual Stream ◽  
Functional Connections ◽  
Free Viewing ◽  
Scene Construction

Scene construction is a key component of memory recall, navigation, and future imagining, and relies on the medial temporal lobes (MTL). A parallel body of work suggests that eye movements may enable the imagination and construction of scenes, even in the absence of external visual input. There are vast structural and functional connections between regions of the MTL and those of the oculomotor system. However, the directionality of connections between the MTL and oculomotor control regions, and how it relates to scene construction, has not been studied directly in human neuroimaging. In the current study, we used dynamic causal modeling (DCM) to investigate this relationship at a mechanistic level using a scene construction task in which participants' eye movements were either restricted (fixed-viewing) or unrestricted (free-viewing). By omitting external visual input, and by contrasting free- versus fixed- viewing, the directionality of neural connectivity during scene construction could be determined. As opposed to when eye movements were restricted, allowing free viewing during construction of scenes strengthened top-down connections from the MTL to the frontal eye fields, and to lower-level cortical visual processing regions, suppressed bottom-up connections along the visual stream, and enhanced vividness of the constructed scenes. Taken together, these findings provide novel, non-invasive evidence for the causal architecture between the MTL memory system and oculomotor system associated with constructing vivid mental representations of scenes.

scholarly journals Neural correlates of subsequent memory-related gaze reinstatement

2021 ◽  
Author(s):  
Jordana S. Wynn ◽  
Zhong-Xu Liu ◽  
Jennifer D. Ryan
Keyword(s):  
Eye Movements ◽  
Basal Ganglia ◽  
Recognition Memory ◽  
Visual Processing ◽  
Memory Task ◽  
Neural Correlates ◽  
Oculomotor Control ◽  
Related Activity ◽  
Pattern Similarity ◽  
Occipital Pole

AbstractMounting evidence linking gaze reinstatement- the recapitulation of encoding-related gaze patterns during retrieval- to behavioral measures of memory suggests that eye movements play an important role in mnemonic processing. Yet, the nature of the gaze scanpath, including its informational content and neural correlates, has remained in question. In the present study, we examined eye movement and neural data from a recognition memory task to further elucidate the behavioral and neural bases of functional gaze reinstatement. Consistent with previous work, gaze reinstatement during retrieval of freely-viewed scene images was greater than chance and predictive of recognition memory performance. Gaze reinstatement was also associated with viewing of informationally salient image regions at encoding, suggesting that scanpaths may encode and contain high-level scene content. At the brain level, gaze reinstatement was predicted by encoding-related activity in the occipital pole and basal ganglia, neural regions associated with visual processing and oculomotor control. Finally, cross-voxel brain pattern similarity analysis revealed overlapping subsequent memory and subsequent gaze reinstatement modulation effects in the parahippocampal place area and hippocampus, in addition to the occipital pole and basal ganglia. Together, these findings suggest that encoding-related activity in brain regions associated with scene processing, oculomotor control, and memory supports the formation, and subsequent recapitulation, of functional scanpaths. More broadly, these findings lend support to Scanpath Theory’s assertion that eye movements both encode, and are themselves embedded in, mnemonic representations.

scholarly journals The knowledge base of the oculomotor system

1997 ◽  
Vol 352 (1358) ◽  
pp. 1231-1239 ◽  
Author(s):  
Michael F. Land ◽  
Sophie Furneaux
Keyword(s):  
Eye Movements ◽  
Visual Processing ◽  
Control Program ◽  
Oculomotor System ◽  
Table Tennis ◽  
Music Reading ◽  
Reading Text ◽  
Memory Buffer ◽  
Movement System ◽  
Motor Actions

In everyday life, eye movements enable the eyes to gather the information required for motor actions. They are thus proactive, anticipating actions rather than just responding to stimuli. This means that the oculomotor system needs to know where to look and what to look for. Using examples from table tennis, driving and music reading we show that the information the eye movement system requires is very varied in origin and highly task specific, and it is suggested that the control program or schema for a particular action must include directions for the oculomotor and visual processing systems. In many activities (reading text and music, typing, steering) processed information is held in a memory buffer for a period of about a second. This permits a match between the discontinuous input from the eyes and continuous motor output, and in particular allows the eyes to be involved in more than one task.

scholarly journals Maintaining fixation does not increase demands on working memory relative to free viewing

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6839 ◽  
Author(s):  
Michael J. Armson ◽  
Jennifer D. Ryan ◽  
Brian Levine
Keyword(s):  
Working Memory ◽  
Eye Movements ◽  
Response Times ◽  
Memory Load ◽  
Memory Performance ◽  
Memory Task ◽  
Oculomotor System ◽  
Finger Tapping ◽  
Long Term Memory ◽  
Free Viewing

The comparison of memory performance during free and fixed viewing conditions has been used to demonstrate the involvement of eye movements in memory encoding and retrieval, with stronger effects at encoding than retrieval. Relative to conditions of free viewing, participants generally show reduced memory performance following sustained fixation, suggesting that unrestricted eye movements benefit memory. However, the cognitive basis of the memory reduction during fixed viewing is uncertain, with possible mechanisms including disruption of visual-mnemonic and/or imagery processes with sustained fixation, or greater working memory demands required for fixed relative to free viewing. To investigate one possible mechanism for this reduction, we had participants perform a working memory task—an auditory n-back task—during free and fixed viewing, as well as a repetitive finger tapping condition, included to isolate the effects of motor interference independent of the oculomotor system. As expected, finger tapping significantly interfered with n-back performance relative to free viewing, as indexed by a decrease in accuracy and increase in response times. By contrast, there was no evidence that fixed viewing interfered with n-back performance relative to free viewing. Our findings failed to support a hypothesis of increased working memory load during fixation. They are consistent with the notion that fixation disrupts long-term memory performance through interference with visual processes.

scholarly journals Masking produces compression of space and time in the absence of eye movements

2014 ◽  
Vol 112 (12) ◽  
pp. 3066-3076 ◽  
Author(s):  
Eckart Zimmermann ◽  
Sabine Born ◽  
Gereon R. Fink ◽  
Patrick Cavanagh
Keyword(s):  
Eye Movements ◽  
Motor Activity ◽  
Human Subjects ◽  
Visual Input ◽  
Ocular Motor ◽  
Visual Stream ◽  
Timing Errors ◽  
New Locations ◽  
Temporal Compression ◽  
Suppression Effects

Whenever the visual stream is abruptly disturbed by eye movements, blinks, masks, or flashes of light, the visual system needs to retrieve the new locations of current targets and to reconstruct the timing of events to straddle the interruption. This process may introduce position and timing errors. We here report that very similar errors are seen in human subjects across three different paradigms when disturbances are caused by either eye movements, as is well known, or, as we now show, masking. We suggest that the characteristic effects of eye movements on position and time, spatial and temporal compression and saccadic suppression of displacement, are consequences of the interruption and the subsequent reconnection and are seen also when visual input is masked without any eye movements. Our data show that compression and suppression effects are not solely a product of ocular motor activity but instead can be properties of a correspondence process that links the targets of interest across interruptions in visual input, no matter what their source.

scholarly journals Closed loop motor-sensory dynamics in human vision

2019 ◽  
Author(s):  
Liron Gruber ◽  
Ehud Ahissar
Keyword(s):  
Eye Movements ◽  
Visual Processing ◽  
Closed Loop ◽  
Open Loop ◽  
Visual Input ◽  
Human Vision ◽  
Visual Inputs ◽  
Eye Motion ◽  
Slow Eye Movements ◽  
The Brain

AbstractVision is obtained with a continuous motion of the eyes. The kinematic analysis of eye motion, during any visual or ocular task, typically reveals two (kinematic) components: saccades, which quickly replace the visual content in the retinal fovea, and drifts, which slowly scan the image after each saccade. While the saccadic exchange of regions of interest (ROIs) is commonly considered to be included in motor-sensory closed-loops, it is commonly assumed that drifts function in an open-loop manner, that is, independent of the concurrent visual input. Accordingly, visual perception is assumed to be based on a sequence of open-loop processes, each initiated by a saccade-triggered retinal snapshot. Here we directly challenged this assumption by testing the dependency of drift kinematics on concurrent visual inputs using real-time gaze-contingent-display. Our results demonstrate a dependency of the trajectory on the concurrent visual input, convergence of speed to condition-specific values and maintenance of selected drift-related motor-sensory controlled variables, all strongly indicative of drifts being included in a closed-loop brain-world process, and thus suggesting that vision is inherently a closed-loop process.Author summaryOur eyes do not function like cameras; it has long been known that we are actively scanning our visual environment in order to see. Moreover, it is commonly accepted that our fast eye movements, saccades, are controlled by the brain and are affected by the sensory input. However, our slow eye movements, the ocular drifts, are often ignored when visual acquisition is analyzed. Accordingly, visual processing is typically assumed to be based on computations performed on saccade-triggered snapshots of the retinal state. Our work strongly challenges this model and provides significant evidence for an alternative model, a cybernetic one. We show that the dynamics of the ocular drifts do not allow, and cannot be explained by, open loop visual acquisition. Instead, our results suggest that visual acquisition is part of a closed-loop process, which dynamically and continuously links the brain to its environment.

scholarly journals Global Saccadic Eye Movements Characterise Artists’ Visual Attention While Drawing

2021 ◽  
pp. 027623742110018
Author(s):  
Suhyun Park ◽  
Louis Wiliams ◽  
Rebecca Chamberlain
Keyword(s):  
Eye Movements ◽  
Visual Processing ◽  
Movement Analysis ◽  
Saccadic Eye Movements ◽  
Future Research ◽  
Eye Movement Analysis ◽  
Free Viewing ◽  
Analysis Technique ◽  
Attentional Shifts ◽  
Representational Drawing

Previous research has shown that artists employ flexible attentional strategies during offline perceptual tasks. The current study explored visual processing online, by tracking the eye movements of artists and non-artists (n=65) while they produced representational drawings of photographic stimuli. The findings revealed that it is possible to differentiate artists from non-artists on the basis of the relative amount of global-to-local saccadic eye movements they make when looking at the target stimulus while drawing, but not in a preparatory free viewing phase. Results indicated that these differences in eye movements are not specifically related to representational drawing ability, and may be a feature of artistic ability more broadly. This eye movement analysis technique may be used in future research to characterise the dynamics of attentional shifts in eye movements while artists are carrying out a range of artistic tasks.

scholarly journals Independent and conjugate eye movements during optokinesis in teleost fish

2002 ◽  
Vol 205 (9) ◽  
pp. 1241-1252 ◽  
Author(s):  
Kerstin A. Fritsches ◽  
N. Justin Marshall
Keyword(s):  
Eye Movements ◽  
Visual Field ◽  
Teleost Fish ◽  
Optokinetic Nystagmus ◽  
Oculomotor System ◽  
Visual Input ◽  
Comparative Approach ◽  
Optokinetic Response ◽  
Different Levels

SUMMARYIn response to movements involving a large part of the visual field, the eyes of vertebrates typically show an optokinetic nystagmus, a response in which both eyes are tightly yoked. Using a comparative approach, this study sets out to establish whether fish with independent spontaneous eye movements show independent optokinetic nystagmus in each eye. Two fish with independent spontaneous eye movements, the pipefish Corythoichthyes intestinalisand the sandlance Limnichthyes fasciatus were compared with the butterflyfish Chaetodon rainfordi, which exhibits tightly yoked eye movements. In the butterflyfish a single whole-field stimulus elicits conjugate optokinesis, whereas the sandlance and pipefish show asynchronous optokinetic movements. In a split drum experiment, when both eyes were stimulated in opposite directions with different speeds, both the sandlance and the pipefish compensated independently with each eye. The optokinetic response in the butterflyfish showed some disconjugacy but was generally confused. When one eye was occluded, the seeing eye was capable of driving the occluded eye in both the butterflyfish and the pipefish but not in the sandlance. Monocular occlusion therefore unmasks a link between the two eyes in the pipefish, which is overridden when both eyes receive visual input. The sandlance never showed any correlation between the eyes during optokinesis in all stimulus conditions. This suggests that there are different levels of linkage between the two eyes in the oculomotor system of teleosts, depending on the visual input.

scholarly journals Alteration of the microsaccadic velocity-amplitude main sequence relationship after visual transients: implications for models of saccade control

2017 ◽  
Vol 117 (5) ◽  
pp. 1894-1910 ◽  
Author(s):  
Antimo Buonocore ◽  
Chih-Yang Chen ◽  
Xiaoguang Tian ◽  
Saad Idrees ◽  
Thomas A. Münch ◽  
...  
Keyword(s):  
Eye Movements ◽  
Main Sequence ◽  
Visual Stimulation ◽  
Peak Velocity ◽  
Rhesus Macaques ◽  
Oculomotor System ◽  
Oculomotor Control ◽  
Velocity Amplitude ◽  
Sequence Relationship ◽  
Saccade Control

Microsaccades occur during gaze fixation to correct for miniscule foveal motor errors. The mechanisms governing such fine oculomotor control are still not fully understood. In this study, we explored microsaccade control by analyzing the impacts of transient visual stimuli on these movements’ kinematics. We found that such kinematics can be altered in systematic ways depending on the timing and spatial geometry of visual transients relative to the movement goals. In two male rhesus macaques, we presented peripheral or foveal visual transients during an otherwise stable period of fixation. Such transients resulted in well-known reductions in microsaccade frequency, and our goal was to investigate whether microsaccade kinematics would additionally be altered. We found that both microsaccade timing and amplitude were modulated by the visual transients, and in predictable manners by these transients’ timing and geometry. Interestingly, modulations in the peak velocity of the same movements were not proportional to the observed amplitude modulations, suggesting a violation of the well-known “main sequence” relationship between microsaccade amplitude and peak velocity. We hypothesize that visual stimulation during movement preparation affects not only the saccadic “Go” system driving eye movements but also a “Pause” system inhibiting them. If the Pause system happens to be already turned off despite the new visual input, movement kinematics can be altered by the readout of additional visually evoked spikes in the Go system coding for the flash location. Our results demonstrate precise control over individual microscopic saccades and provide testable hypotheses for mechanisms of saccade control in general. NEW & NOTEWORTHY Microsaccadic eye movements play an important role in several aspects of visual perception and cognition. However, the mechanisms for microsaccade control are still not fully understood. We found that microsaccade kinematics can be altered in a systematic manner by visual transients, revealing a previously unappreciated and exquisite level of control by the oculomotor system of even the smallest saccades. Our results suggest precise temporal interaction between visual, motor, and inhibitory signals in microsaccade control.

scholarly journals Probing Bottom-up Processing with Multistable Images

2009 ◽  
Vol 1 (3) ◽  
Author(s):  
Ozgur E. Akman ◽  
Richard A. Clement ◽  
David S. Broomhead ◽  
Sabira Mannan ◽  
Ian Moorhead ◽  
...  
Keyword(s):  
Eye Movements ◽  
Visual Processing ◽  
Top Down ◽  
Bottom Up ◽  
Free Viewing ◽  
Pattern Comparison ◽  
Selection Of

The selection of fixation targets involves a combination of top-down and bottom-up processing. The role of bottom-up processing can be enhanced by using multistable stimuli because their constantly changing appearance seems to depend predominantly on stimulusdriven factors. We used this approach to investigate whether visual processing models based on V1 need to be extended to incorporate specific computations attributed to V4. Eye movements of 8 subjects were recorded during free viewing of the Marroquin pattern in which illusory circles appear and disappear. Fixations were concentrated on features arranged in concentric rings within the pattern. Comparison with simulated fixation data demonstrated that the saliency of these features can be predicted with appropriate weighting of lateral connections in existing V1 models.

scholarly journals Blink adaptation for target displacements in depth

2020 ◽  
Author(s):  
Arnab Biswas ◽  
Gerrit W Maus
Keyword(s):  
Eye Movements ◽  
Oculomotor System ◽  
Oculomotor Control ◽  
Gaze Control ◽  
Eye Blink ◽  
Position Errors ◽  
Gaze Stability ◽  
Corrective Effect ◽  
Gaze Position

To maintain gaze stability, the oculomotor system needs to correct gaze position errors that may emerge subsequent to an eye blink. It has been shown that artificially induced gaze position errors, when a target is displaced by a consistent mount during an eye blink, lead to a recalibration of gaze control during the blink, a process termed ‘blink adaptation’ (Lau & Maus, 2018; Maus et al., 2017). In the present study, we investigate if this corrective mechanism also occurs for errors induced by displacing the target in depth during an eye blink. Across two conditions, subjects were asked to fixate on a target, whose disparity was increased or decreased when the eyelids were completely closed during a blink. We found that participants recalibrated their gaze for both conditions, with more automatic vergence eye movements occurring during the blink in the direction required to correct for the disjunctive step of the target. This corrective effect was generally larger for the condition with decreasing stimulus disparity as compared to increasing disparity. Our results reveal that blink adaptation is a general recalibration mechanism in oculomotor control, which can be driven by both monocular errors that correct for conjugate gaze targeting errors, or by binocular errors that correct for disconjugate vergence errors.

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