TMS Pulses on the Frontal Eye Fields Break Coupling Between Visuospatial Attention and Eye Movements

2007 ◽  
Vol 98 (5) ◽  
pp. 2765-2778 ◽  
Author(s):  
S.F.W. Neggers ◽  
W. Huijbers ◽  
C. M. Vrijlandt ◽  
B.N.S. Vlaskamp ◽  
D.J.L.G. Schutter ◽  
...  
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Visual Processing ◽  
Discrimination Performance ◽  
Visuospatial Attention ◽  
Movement Direction ◽  
Frontal Eye Fields ◽  
Functional Magnetic Resonance ◽  
And Shifts ◽  
Saccade Preparation

While preparing a saccadic eye movement, visual processing of the saccade goal is prioritized. Here, we provide evidence that the frontal eye fields (FEFs) are responsible for this coupling between eye movements and shifts of visuospatial attention. Functional magnetic resonance imaging (fMRI)–guided transcranial magnetic stimulation (TMS) was applied to the FEFs 30 ms before a discrimination target was presented at or next to the target of a saccade in preparation. Results showed that the well-known enhancement of discrimination performance on locations to which eye movements are being prepared was diminished by TMS contralateral to eye movement direction. Based on the present and other reports, we propose that saccade preparatory processes in the FEF affect selective visual processing within the visual cortex through feedback projections, in that way coupling saccade preparation and visuospatial attention.

fMRI-Guided TMS on Cortical Eye Fields: The Frontal But Not Intraparietal Eye Fields Regulate the Coupling Between Visuospatial Attention and Eye Movements

2009 ◽  
Vol 102 (6) ◽  
pp. 3469-3480 ◽  
Author(s):  
H. M. Van Ettinger-Veenstra ◽  
W. Huijbers ◽  
T. P. Gutteling ◽  
M. Vink ◽  
J. L. Kenemans ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Eye Movements ◽  
Visual Processing ◽  
Discrimination Performance ◽  
Visual Image ◽  
Single Pulse ◽  
Visuospatial Attention ◽  
Movement Direction ◽  
Key Factor ◽  
And Shifts

It is well known that parts of a visual scene are prioritized for visual processing, depending on the current situation. How the CNS moves this focus of attention across the visual image is largely unknown, although there is substantial evidence that preparation of an action is a key factor. Our results support the view that direct corticocortical feedback connections from frontal oculomotor areas to the visual cortex are responsible for the coupling between eye movements and shifts of visuospatial attention. Functional magnetic resonance imaging (fMRI)–guided transcranial magnetic stimulation (TMS) was applied to the frontal eye fields (FEFs) and intraparietal sulcus (IPS). A single pulse was delivered 60, 30, or 0 ms before a discrimination target was presented at, or next to, the target of a saccade in preparation. Results showed that the known enhancement of discrimination performance specific to locations to which eye movements are being prepared was enhanced by early TMS on the FEF contralateral to eye movement direction, whereas TMS on the IPS resulted in a general performance increase. The current findings indicate that the FEF affects selective visual processing within the visual cortex itself through direct feedback projections.

Visual Field Accuracy and Eye Movement Direction: A Child's Eye View

1980 ◽  
Vol 50 (2) ◽  
pp. 631-636
Author(s):  
Evans Mandes
Keyword(s):  
Eye Movements ◽  
Visual Field ◽  
Eye Movement ◽  
Visual Fields ◽  
Movement Direction

Post-exposural eye movements were studied in 32 adults and 24 7-yr.-old children. Stimuli were binary figures exposed tachistoscopically in both visual fields simultaneously. The data showed significant correlations between direction of eye movement and locus of recognition for both children and adults. No significant differences were found in frequencies of eye movements of children and adults. The data are interpreted in terms of the facilitative effects of post-exposural eye movements upon perception for both groups.

Optokinetic Eye Movements Elicited by Radial Optic Flow in the Macaque Monkey

1998 ◽  
Vol 79 (3) ◽  
pp. 1461-1480 ◽  
Author(s):  
Markus Lappe ◽  
Martin Pekel ◽  
Klaus-Peter Hoffmann
Keyword(s):  
Eye Movements ◽  
Flow Field ◽  
Eye Movement ◽  
Optic Flow ◽  
Macaque Monkey ◽  
Flow Fields ◽  
Movement Direction ◽  
Slow Phase ◽  
Eye Position ◽  
Self Motion

Lappe, Markus, Martin Pekel, and Klaus-Peter Hoffmann. Optokinetic eye movements elicited by radial optic flow in the macaque monkey. J. Neurophysiol. 79: 1461–1480, 1998. We recorded spontaneous eye movements elicited by radial optic flow in three macaque monkeys using the scleral search coil technique. Computer-generated stimuli simulated forward or backward motion of the monkey with respect to a number of small illuminated dots arranged on a virtual ground plane. We wanted to see whether optokinetic eye movements are induced by radial optic flow stimuli that simulate self-movement, quantify their parameters, and consider their effects on the processing of optic flow. A regular pattern of interchanging fast and slow eye movements with a frequency of 2 Hz was observed. When we shifted the horizontal position of the focus of expansion (FOE) during simulated forward motion (expansional optic flow), median horizontal eye position also shifted in the same direction but only by a smaller amount; for simulated backward motion (contractional optic flow), median eye position shifted in the opposite direction. We relate this to a change in Schlagfeld typically observed in optokinetic nystagmus. Direction and speed of slow phase eye movements were compared with the local flow field motion in gaze direction (the foveal flow). Eye movement direction matched well the foveal motion. Small systematic deviations could be attributed to an integration of the global motion pattern. Eye speed on average did not match foveal stimulus speed, as the median gain was only ∼0.5–0.6. The gain was always lower for expanding than for contracting stimuli. We analyzed the time course of the eye movement immediately after each saccade. We found remarkable differences in the initial development of gain and directional following for expansion and contraction. For expansion, directional following and gain were initially poor and strongly influenced by the ongoing eye movement before the saccade. This was not the case for contraction. These differences also can be linked to properties of the optokinetic system. We conclude that optokinetic eye movements can be elicited by radial optic flow fields simulating self-motion. These eye movements are linked to the parafoveal flow field, i.e., the motion in the direction of gaze. In the retinal projection of the optic flow, such eye movements superimpose retinal slip. This results in complex retinal motion patterns, especially because the gain of the eye movement is small and variable. This observation has special relevance for mechanisms that determine self-motion from retinal flow fields. It is necessary to consider the influence of eye movements in optic flow analysis, but our results suggest that direction and speed of an eye movement should be treated differently.

Localization of human frontal eye fields: anatomical and functional findings of functional magnetic resonance imaging and intracerebral electrical stimulation

2001 ◽  
Vol 95 (5) ◽  
pp. 804-815 ◽  
Author(s):  
Elie Lobel ◽  
Philippe Kahane ◽  
Ute Leonards ◽  
Marie-Hélène Grosbras ◽  
Stéphane Lehéricy ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Eye Movements ◽  
Magnetic Resonance ◽  
3 Tesla ◽  
Frontal Eye Fields ◽  
Precentral Gyrus ◽  
Functional Magnetic Resonance ◽  
Content Type ◽  
Cortical Areas ◽  
Fine Print

Object. The goal of this study was to investigate the anatomical localization and functional role of human frontal eye fields (FEFs) by comparing findings from two independently conducted studies. Methods. In the first study, 3-tesla functional magnetic resonance (fMR) imaging was performed in 14 healthy volunteers divided into two groups: the first group executed self-paced voluntary saccades in complete darkness and the second group repeated newly learned or familiar sequences of saccades. In the second study, intracerebral electrical stimulation (IES) was performed in 38 patients with epilepsy prior to surgery, and frontal regions where stimulation induced versive eye movements were identified. These studies showed that two distinct oculomotor areas (OMAs) could be individualized in the region classically corresponding to the FEFs. One OMA was consistently located at the intersection of the superior frontal sulcus with the fundus of the superior portion of the precentral sulcus, and was the OMA in which saccadic eye movements could be the most easily elicited by electrical stimulation. The second OMA was located more laterally, close to the surface of the precentral gyrus. The fMR imaging study and the IES study demonstrated anatomical and stereotactic agreement in the identification of these cortical areas. Conclusions. These findings indicate that infracentimetric localization of cortical areas can be achieved by measuring the vascular signal with the aid of 3-tesla fMR imaging and that neuroimaging and electrophysiological recording can be used together to obtain a better understanding of the human cortical functional anatomy.

scholarly journals The Contributions of Eye Gaze Fixations and Target-Lure Similarity to Behavioral and fMRI Indices of Pattern Separation and Pattern Completion

2021 ◽  
Author(s):  
Daniel K Bjornn ◽  
Julie Van ◽  
Brock Kirwan
Keyword(s):  
Eye Movements ◽  
False Alarm ◽  
Eye Movement ◽  
Eye Gaze ◽  
Recognition Task ◽  
Discrimination Performance ◽  
Pattern Separation ◽  
Fmri Data ◽  
Pattern Completion ◽  
Gaze Fixations

Pattern separation and pattern completion are generally studied in humans using mnemonic discrimination tasks such as the Mnemonic Similarity Task (MST) where participants identify similar lures and repeated items from a series of images. Failures to correctly discriminate lures are thought to reflect a failure of pattern separation and a propensity toward pattern completion. Recent research has challenged this perspective, suggesting that poor encoding rather than pattern completion accounts for the occurrence of false alarm responses to similar lures. In two experiments, participants completed a continuous recognition task version of the MST while eye movement (Experiment 1 and 2) and fMRI data (Experiment 2) were collected. While we replicated the result that fixation counts at study predicted accuracy on lure trials, we found that target-lure similarity was a much stronger predictor of accuracy on lure trials across both experiments. Lastly, we found that fMRI activation changes in the hippocampus were significantly correlated with the number of fixations at study for correct but not incorrect mnemonic discrimination judgments when controlling for target-lure similarity. Our findings indicate that while eye movements during encoding predict subsequent hippocampal activation changes, mnemonic discrimination performance is better described by pattern separation and pattern completion processes that are influenced by target-lure similarity than simply poor encoding.

Canceling of Pursuit and Saccadic Eye Movements in Humans and Monkeys

2003 ◽  
Vol 89 (6) ◽  
pp. 2984-2999 ◽  
Author(s):  
Krista Kornylo ◽  
Natalie Dill ◽  
Melissa Saenz ◽  
Richard J. Krauzlis
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Inhibitory Control ◽  
Saccadic Eye Movements ◽  
Preceding Trial ◽  
Stop Signal ◽  
Motor Pathways ◽  
The Subject ◽  
Saccade Preparation ◽  
Countermanding Task

The countermanding paradigm provides a useful tool for examining the mechanisms responsible for canceling eye movements. The key feature of this paradigm is that, on a minority of trials, a stop signal is introduced some time after the appearance of the target, indicating that the subject should cancel the incipient eye movement. If the delay in giving the stop signal is too long, subjects fail to cancel the eye movement to the target stimulus. By modeling this performance as a race between a go process triggered by the appearance of the target and a stop process triggered by the appearance of the stop signal, it is possible to estimate the processing interval associated with canceling the movement. We have now used this paradigm to analyze the canceling of pursuit and saccades. For pursuit, we obtained consistent estimates of the stop process regardless of our technique or assumptions—it took 50–60 ms to cancel pursuit in both humans and monkeys. For saccades, we found different values depending on our assumptions. When we assumed that saccade preparation was under inhibitory control up until movement onset, we found that saccades took longer to cancel (humans: ∼110, monkeys: ∼80 ms) than pursuit. However, when we assumed that saccade preparation includes a final “ballistic” interval not under inhibitory control, we found that the same rapid stop process that accounted for our pursuit results could also account for the canceling of saccades. We favor this second interpretation because canceling pursuit or saccades amounts to maintaining a state of fixation, and it is more parsimonious to assume that this involves a single inhibitory process associated with the fixation system, rather than two separate inhibitory processes depending on which type of eye movement will not be made. From our behavioral data, we estimate that this ballistic interval has a duration of 9–25 ms in monkeys, consistent with the known physiology of the final motor pathways for saccades, although we obtained longer values in humans (28–60 ms). Finally, we examined the effect of trial sequence during the countermanding task and found that pursuit and saccade latencies tended to be longer if the previous trial contained a stop signal than if it did not; these increases occurred regardless of whether the preceding trial was associated with the same or different type of eye movement. Together, these results suggest that a common inhibitory mechanism regulates the initiation of pursuit and saccades.

Primate frontal eye fields. III. Maintenance of a spatially accurate saccade signal

1990 ◽  
Vol 64 (2) ◽  
pp. 489-508 ◽  
Author(s):  
M. E. Goldberg ◽  
C. J. Bruce
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Saccadic Eye Movements ◽  
Frontal Eye Field ◽  
Frontal Eye Fields ◽  
Significant Activity ◽  
Double Step ◽  
Retinal Stimulation ◽  
Movement Field ◽  
The Right

1. We studied the activity of single neurons in the monkey frontal eye fields during oculomotor tasks designed to assess the activity of these neurons when there was a dissonance between the spatial location of a target and its position on the retina. 2. Neurons with presaccadic activity were first studied to determine their receptive or movement fields and to classify them as visual, visuomovement, or movement cells with the use of the criteria described previously (Bruce and Goldberg 1985). The neurons were then studied by the use of double-step tasks that dissociated the retinal coordinates of visual targets from the dimensions of saccadic eye movements necessary to acquire those targets. These tasks required that the monkeys make two successive saccades to follow two sequentially flashed targets. Because the second target disappeared before the first saccade occurred, the dimensions of the second saccade could not be based solely on the retinal coordinates of the target but also depended on the dimensions of the first saccade. We used two versions of the double-step task. In one version neither target appeared in the cell's receptive or movement field, but the second eye movement was the optimum amplitude and direction for the cell (right-EM/wrong-RF task). In the other the second stimulus appeared in the cell's receptive field, but neither eye movement was appropriate for the cell (wrong-EM/right-RF task). 3. Most frontal-eye-field cells discharged in the right-EM/wrong-RF version of the double-step task. Their discharge began after the first saccade and continued until the second saccade was made. They usually discharged even on occasional trials in which the monkey failed to make the second saccade. They discharged much less, or not at all, in the wrong-EM/right-RF version of the double-step paradigm. Thus most presaccadic cells in the frontal eye fields were tuned to the dimensions of saccadic eye movements rather than to the coordinates of retinal stimulation. 4. Eleven movement cells (including 1 which also had independent postsaccadic activity for saccades opposite its presaccadic movement field) were studied, and all had significant activity in the right-EM/wrong-RF task. 5. Almost all (28/32) visuomovement cells, including 12 with independent postsaccadic activity, discharged in the right-EM/wrong-RF task. None of the four that failed had independent postsaccadic activity. 6. The majority (26/40) of visual cells were responsive in the right-EM/wrong-RF task.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Selective modulation of visual sensitivity during fixation

2018 ◽  
Vol 119 (6) ◽  
pp. 2059-2067 ◽  
Author(s):  
Chris Scholes ◽  
Paul V. McGraw ◽  
Neil W. Roach
Keyword(s):  
Eye Movements ◽  
Spatial Frequency ◽  
Contrast Sensitivity ◽  
Eye Movement ◽  
Visual Processing ◽  
Spatial Scales ◽  
Gain Control ◽  
Visual Sensitivity ◽  
Ocular Movements ◽  
Spatial Frequencies

During periods of steady fixation, we make small-amplitude ocular movements, termed microsaccades, at a rate of 1–2 every second. Early studies provided evidence that visual sensitivity is reduced during microsaccades—akin to the well-established suppression associated with larger saccades. However, the results of more recent work suggest that microsaccades may alter retinal input in a manner that enhances visual sensitivity to some stimuli. Here we parametrically varied the spatial frequency of a stimulus during a detection task and tracked contrast sensitivity as a function of time relative to microsaccades. Our data reveal two distinct modulations of sensitivity: suppression during the eye movement itself and facilitation after the eye has stopped moving. The magnitude of suppression and facilitation of visual sensitivity is related to the spatial content of the stimulus: suppression is greatest for low spatial frequencies, while sensitivity is enhanced most for stimuli of 1–2 cycles/°, spatial frequencies at which we are already most sensitive in the absence of eye movements. We present a model in which the tuning of suppression and facilitation is explained by delayed lateral inhibition between spatial frequency channels. Our data show that eye movements actively modulate visual sensitivity even during fixation: the detectability of images at different spatial scales can be increased or decreased depending on when the image occurs relative to a microsaccade. NEW & NOTEWORTHY Given the frequency with which we make microsaccades during periods of fixation, it is vital that we understand how they affect visual processing. We demonstrate two selective modulations of contrast sensitivity that are time-locked to the occurrence of a microsaccade: suppression of low spatial frequencies during each eye movement and enhancement of higher spatial frequencies after the eye has stopped moving. These complementary changes may arise naturally because of sluggish gain control between spatial channels.

scholarly journals Human Frontal Eye Fields and Visual Search

2003 ◽  
Vol 89 (6) ◽  
pp. 3340-3343 ◽  
Author(s):  
Neil G. Muggleton ◽  
Chi-Hung Juan ◽  
Alan Cowey ◽  
Vincent Walsh
Keyword(s):  
Visual Search ◽  
Eye Movements ◽  
False Alarm ◽  
Eye Movement ◽  
Magnetic Stimulation ◽  
Search Task ◽  
Scene Analysis ◽  
Frontal Eye Fields ◽  
Feature Search ◽  
Search Tasks

Recent physiological recording studies in monkeys have suggested that the frontal eye fields (FEFs) are involved in visual scene analysis even when eye movement commands are not required. We examined this proposed function of the human frontal eye fields during performance of visual search tasks in which difficulty was matched and eye movements were neither necessary nor required. Magnetic stimulation over FEF modulated performance on a conjunction search task and a simple feature search task in which the target was unpredictable from trial to trial, primarily by increasing false alarm responses. Simple feature search with a predictable target was not affected. The results establish that human FEFs are critical to visual selection, regardless of the need to generate a saccade command.

scholarly journals Is covert spatial orienting embodied or disembodied cognition? A historical review

2019 ◽  
Vol 73 (1) ◽  
pp. 20-28 ◽  
Author(s):  
Raymond M Klein
Keyword(s):  
Eye Movements ◽  
Embodied Cognition ◽  
Historical Review ◽  
Visuospatial Attention ◽  
Endogenous Control ◽  
Spatial Orienting ◽  
And Shifts ◽  
Attention Shifts

The possible relations between eye movements and shifts of attention are considered in the context of the contemporary proposal of embodied cognition. The focus of this historical review is Klein’s oculomotor readiness hypothesis for how visuospatial attention might be allocated when under endogenous control. When eye movements are actually executed, attention shifts in advance of these movements. But when eye movements are prepared but not executed, shifts of attention are not observed. Conversely, when attention is allocated endogenously and covertly to a location in space, eye movements to that location are not prepared. These findings suggest that covert spatial orienting when under endogenous control is more dis-embodied than embodied cognition.

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