scholarly journals Expansion of Visual Space During Optokinetic Afternystagmus (OKAN)

2008 ◽  
Vol 99 (5) ◽  
pp. 2470-2478 ◽  
Author(s):  
André Kaminiarz ◽  
Bart Krekelberg ◽  
Frank Bremmer
Keyword(s):  
Eye Movements ◽  
Visual Space ◽  
Eye Position ◽  
Control Mechanisms ◽  
Position Information ◽  
Fast Phase ◽  
Optokinetic Afternystagmus ◽  
Perceptual Stability ◽  
Voluntary Eye Movements ◽  
The Brain

The mechanisms underlying visual perceptual stability are usually investigated using voluntary eye movements. In such studies, errors in perceptual stability during saccades and pursuit are commonly interpreted as mismatches between actual eye position and eye-position signals in the brain. The generality of this interpretation could in principle be tested by investigating spatial localization during reflexive eye movements whose kinematics are very similar to those of voluntary eye movements. Accordingly, in this study, we determined mislocalization of flashed visual targets during optokinetic afternystagmus (OKAN). These eye movements are quite unique in that they occur in complete darkness and are generated by subcortical control mechanisms. We found that during horizontal OKAN slow phases, subjects mislocalize targets away from the fovea in the horizontal direction. This corresponds to a perceived expansion of visual space and is unlike mislocalization found for any other voluntary or reflexive eye movement. Around the OKAN fast phases, we found a bias in the direction of the fast phase prior to its onset and opposite to the fast-phase direction thereafter. Such a biphasic modulation has also been reported in the temporal vicinity of saccades and during optokinetic nystagmus (OKN). A direct comparison, however, showed that the modulation during OKAN was much larger and occurred earlier relative to fast-phase onset than during OKN. A simple mismatch between the current eye position and the eye-position signal in the brain is unlikely to explain such disparate results across similar eye movements. Instead, these data support the view that mislocalization arises from errors in eye-centered position information.

Eye position effects in saccadic adaptation

2011 ◽  
Vol 106 (5) ◽  
pp. 2536-2545 ◽  
Author(s):  
Katharina Havermann ◽  
Eckart Zimmermann ◽  
Markus Lappe
Keyword(s):  
Eye Movements ◽  
Visual Space ◽  
Initial Position ◽  
Head Movements ◽  
Eye Position ◽  
Saccade Amplitude ◽  
Position Effects ◽  
Position Information ◽  
Saccadic Adaptation ◽  
Visual Error

Saccades are used by the visual system to explore visual space with the high accuracy of the fovea. The visual error after the saccade is used to adapt the control of subsequent eye movements of the same amplitude and direction in order to keep saccades accurate. Saccadic adaptation is thus specific to saccade amplitude and direction. In the present study we show that saccadic adaptation is also specific to the initial position of the eye in the orbit. This is useful, because saccades are normally accompanied by head movements and the control of combined head and eye movements depends on eye position. Many parts of the saccadic system contain eye position information. Using the intrasaccadic target step paradigm, we adaptively reduced the amplitude of reactive saccades to a suddenly appearing target at a selective position of the eyes in the orbitae and tested the resulting amplitude changes for the same saccade vector at other starting positions. For central adaptation positions the saccade amplitude reduction transferred completely to eccentric starting positions. However, for adaptation at eccentric starting positions, there was a reduced transfer to saccades from central starting positions or from eccentric starting positions in the opposite hemifield. Thus eye position information modifies the transfer of saccadic amplitude changes in the adaptation of reactive saccades. A gain field mechanism may explain the eye position dependence found.

The Main Sequence of Human Optokinetic Afternystagmus (OKAN)

2009 ◽  
Vol 101 (6) ◽  
pp. 2889-2897 ◽  
Author(s):  
Andre Kaminiarz ◽  
Kerstin Königs ◽  
Frank Bremmer
Keyword(s):  
Neural Networks ◽  
Eye Movements ◽  
Main Sequence ◽  
Critical Role ◽  
Saccade Target ◽  
Control Mechanisms ◽  
Visually Guided ◽  
Background Characteristics ◽  
Optokinetic Afternystagmus

Different types of fast eye movements, including saccades and fast phases of optokinetic nystagmus (OKN) and optokinetic afternystagmus (OKAN), are coded by only partially overlapping neural networks. This is a likely cause for the differences that have been reported for the dynamic parameters of fast eye movements. The dependence of two of these parameters—peak velocity and duration—on saccadic amplitude has been termed “main sequence.” The main sequence of OKAN fast phases has not yet been analyzed. These eye movements are unique in that they are generated by purely subcortical control mechanisms and that they occur in complete darkness. In this study, we recorded fast phases of OKAN and OKN as well as visually guided and spontaneous saccades under identical background conditions because background characteristics have been reported to influence the main sequence of saccades. Our data clearly show that fast phases of OKAN and OKN differ with respect to their main sequence. OKAN fast phases were characterized by their lower peak velocities and longer durations compared with those of OKN fast phases. Furthermore we found that the main sequence of spontaneous saccades depends heavily on background characteristics, with saccades in darkness being slower and lasting longer. On the contrary, the main sequence of visually guided saccades depended on background characteristics only very slightly. This implies that the existence of a visual saccade target largely cancels out the effect of background luminance. Our data underline the critical role of environmental conditions (light vs. darkness), behavioral tasks (e.g., spontaneous vs. visually guided), and the underlying neural networks for the exact spatiotemporal characteristics of fast eye movements.

Recasting the Smooth Pursuit Eye Movement System

2004 ◽  
Vol 91 (2) ◽  
pp. 591-603 ◽  
Author(s):  
Richard J. Krauzlis
Keyword(s):  
Eye Movements ◽  
Brain Stem ◽  
Smooth Pursuit ◽  
Visual Motion ◽  
Saccadic Eye Movements ◽  
Extrastriate Cortex ◽  
High Acuity ◽  
Voluntary Eye Movements ◽  
New Perspective ◽  
The Brain

Primates use a combination of smooth pursuit and saccadic eye movements to stabilize the retinal image of selected objects within the high-acuity region near the fovea. Pursuit has traditionally been viewed as a relatively automatic behavior, driven by visual motion signals and mediated by pathways that connect visual areas in the cerebral cortex to motor regions in the cerebellum. However, recent findings indicate that this view needs to be reconsidered. Rather than being controlled primarily by areas in extrastriate cortex specialized for processing visual motion, pursuit involves an extended network of cortical areas, and, of these, the pursuit-related region in the frontal eye fields appears to exert the most direct influence. The traditional pathways through the cerebellum are important, but there are also newly identified routes involving structures previously associated with the control of saccades, including the basal ganglia, the superior colliculus, and nuclei in the brain stem reticular formation. These recent findings suggest that the pursuit system has a functional architecture very similar to that of the saccadic system. This viewpoint provides a new perspective on the processing steps that occur as descending control signals interact with circuits in the brain stem and cerebellum responsible for gating and executing voluntary eye movements. Although the traditional view describes pursuit and saccades as two distinct neural systems, it may be more accurate to consider the two movements as different outcomes from a shared cascade of sensory–motor functions.

Does the world rock when the eyes roll?

2000 ◽  
Vol 59 (2) ◽  
pp. 89-101 ◽  
Author(s):  
Fred W. Mast
Keyword(s):  
Inertial Force ◽  
Neural Mechanism ◽  
Visual Orientation ◽  
Eye Position ◽  
Position Information ◽  
Reference Information ◽  
Ocular Counterroll ◽  
Short Line Segment ◽  
Visual Vertical ◽  
The Brain

When the head is inclined sideways, the eyes are counter-rotated with respect to the head (ocular-counterroll, OCR). In man, the gain of OCR in static body tilts is limited to about 10% of the angle of roll tilt, which suggests that its function is vestigial. However, it is still unclear how the residual OCR is related to the perceived orientation of visual stimuli. Wade and Curthoys (1997) claim that the brain does not “take into account” the OCR, so that the eye position directly interferes with perception of visual orientation. Alternately, it has been argued that OCR is partly compensated by an extraretinal eye-position information such as, e.g., an efference copy ( Haustein, 1992 ; Haustein & Mittelstaedt, 1990 ). The two experiments reported in this study are targeted towards critically examining this inter-relation between OCR and perceived visual orientation. The latter was assessed via the subjective visual vertical, SVV, which is determined when a subject judges the orientation of an indicator (e.g., a short line segment) as apparently vertical. The OCR was measured by using a video-oculographic system. In Experiment 1, a human centrifuge was used to test the effect of an increase of the gravito-inertial force (GIF) on SVV and OCR. Experiment 2 was inspired by the fact that OCR can also be elicited during “barbecue rotation”. Again, it was the aim to compare OCR and SVV in different body positions, such as pure roll and barbecue rotated tilts. The present study provides convincing experimental evidence that SVV is widely uninfluenced by the course of OCR. Increasing the GIF in Experiment 1 had a divergent effect on SVV and OCR; the gain of OCR increases whereas the SVV changed differently, at obtuse tilt angles even in the opposite direction. OCR and SVV were again found to dissociate in Experiment 2, which emphasizes the fact that the SVV and OCR are not controlled by the same neural mechanism, but rather use different spatial reference information.

Dynamic Circuitry for Updating Spatial Representations. II. Physiological Evidence for Interhemispheric Transfer in Area LIP of the Split-Brain Macaque

2005 ◽  
Vol 94 (5) ◽  
pp. 3249-3258 ◽  
Author(s):  
Laura M. Heiser ◽  
Rebecca A. Berman ◽  
Richard C. Saunders ◽  
Carol L. Colby
Keyword(s):  
Eye Movements ◽  
Visual Representations ◽  
The Other ◽  
Spatial Representations ◽  
Lateral Intraparietal Area ◽  
Split Brain ◽  
Perceptual Stability ◽  
Visual Hemifield ◽  
Principal Finding ◽  
The Brain

With each eye movement, a new image impinges on the retina, yet we do not notice any shift in visual perception. This perceptual stability indicates that the brain must be able to update visual representations to take our eye movements into account. Neurons in the lateral intraparietal area (LIP) update visual representations when the eyes move. The circuitry that supports these updated representations remains unknown, however. In this experiment, we asked whether the forebrain commissures are necessary for updating in area LIP when stimulus representations must be updated from one visual hemifield to the other. We addressed this question by recording from LIP neurons in split-brain monkeys during two conditions: stimulus traces were updated either across or within hemifields. Our expectation was that across-hemifield updating activity in LIP would be reduced or abolished after transection of the forebrain commissures. Our principal finding is that LIP neurons can update stimulus traces from one hemifield to the other even in the absence of the forebrain commissures. This finding provides the first evidence that representations in parietal cortex can be updated without the use of direct cortico-cortical links. The second main finding is that updating activity in LIP is modified in the split-brain monkey: across-hemifield signals are reduced in magnitude and delayed in onset compared with within-hemifield signals, which indicates that the pathways for across-hemifield updating are less effective in the absence of the forebrain commissures. Together these findings reveal a dynamic circuit that contributes to updating spatial representations.

Neuronal death of the cancellation theory?

1994 ◽  
Vol 17 (2) ◽  
pp. 274-275
Author(s):  
Claude Prablanc
Keyword(s):  
Eye Movements ◽  
Clinical Observation ◽  
Saccadic Eye Movements ◽  
Analytic Solutions ◽  
Visual Stability ◽  
Perceptual Stability ◽  
Stable Representation ◽  
The Subject ◽  
The Stability ◽  
The Brain

The question of how the brain can construct a stable representation of the external world despite eye movements is a very old one. If there have been some wrong statements of problems (such as the inverted retinal image), other statements are less naive and have led to analytic solutions possibly adopted by the brain to counteract the spurious effects of eye movements. Following the MacKay (1973) objections to the analytic view of perceptual stability, Bridgeman et al. claim that the idea that signals canceling the effects of saccadic eye movements are needed is also a misconception, as is the claim that stability and position encoding are two distinct problems. It must be remembered, however, that what made the theory of “cancellation” formulated by von Holst and Mittelstaedt (1950) so appealing was the clinical observation of perceptual instability following ocular paralysis. Following the concept of corollary discharge, the theory of efference copy had the advantage of simultaneously solving three problems: the stability of the visual world during the saccade, the same visual stability across saccades, and the visual constancy problem of allowing the subject to know where an object in space is.

Modulation of pursuit eye movements by stimulation of cortical areas MT and MST

1989 ◽  
Vol 62 (1) ◽  
pp. 31-47 ◽  
Author(s):  
H. Komatsu ◽  
R. H. Wurtz
Keyword(s):  
Eye Movements ◽  
Visual Motion ◽  
Directional Bias ◽  
Position Information ◽  
Temporal Area ◽  
Pursuit Eye Movements ◽  
Visual Motion Processing ◽  
Pursuit System ◽  
Pursuit Velocity ◽  
The Brain

1. Many cells in the superior temporal sulcus (STS) of the monkey that represent the foveal region of the visual field discharge during pursuit eye movements. Damage to these areas produces a deficit in the maintenance of pursuit eye movements when the target towards the side of the brain with the lesion. In the present experiments, we electrically stimulated these areas to better localize and understand the mechanisms underlying this directional pursuit deficit. 2. Monkeys were trained to pursue a moving target using a step-ramp task in which the target first stepped to an eccentric position and then moved smoothly across the screen. Trains of stimulation were applied after the monkey had begun to pursue the target to study stimulation effects of maintenance of pursuit. 3. Stimulation during pursuit frequently produced eye acceleration toward the side of the brain stimulated. Eye speed increased during pursuit toward the side stimulated and decreased during pursuit away from the side stimulated. This increase in velocity toward the side of the brain where stimulation presumably activated cells is consistent with the decrease in pursuit velocity toward the side of the brain after cells were removed by chemical lesions. 4. The increase or decrease in pursuit speed following stimulation produced a slip of the target on the retina. The pursuit system seemed to be insensitive to this slip during the period of stimulation, however, since the effect of stimulation during pursuit of a stabilized image (open-loop condition) was similar to that resulting from stimulation under normal pursuit conditions (closed-loop). This insensitivity to visual motion during stimulation suggests that the stimulation substitutes for that visual input. 5. The separation of eye and target position that resulted from stimulation did produce catch-up saccades. This provides added evidence that alteration of middle temporal area (MT) and medial superior temporal area (MST) modifies visual-motion but not visual-position information. 6. Stimulation that produced eye acceleration during pursuit produced only a slight effect during fixation of a stationary target. The effectiveness of the stimulation also increased as the speed of the pursuit increased between 5 and 25 degrees/s. These observations, which show that pursuit velocity altered the effect of stimulation, suggest that the stimulation acted on visual motion processing before information about the pursuit movement itself is incorporated. Since this stimulation produces directional pursuit effects, we hypothesize that the directional bias for pursuit originates in the visual signal conveyed to the pursuit system.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Eye position signals in the dorsal pulvinar during fixation and goal-directed saccades

2019 ◽  
Author(s):  
Lukas Schneider ◽  
Adan-Ulises Dominguez-Vargas ◽  
Lydia Gibson ◽  
Igor Kagan ◽  
Melanie Wilke
Keyword(s):  
Reference Frame ◽  
Visual Memory ◽  
Reference Frames ◽  
Gaze Direction ◽  
Small Subset ◽  
Eye Position ◽  
Position Information ◽  
Cortical Areas ◽  
Perceptual Stability ◽  
Postural Changes

AbstractMost sensorimotor cortical areas contain eye position information thought to ensure perceptual stability across saccades and underlie spatial transformations supporting goal-directed actions. One pathway by which eye position signals could be relayed to and across cortical areas is via the dorsal pulvinar. Several studies demonstrated saccade-related activity in the dorsal pulvinar and we have recently shown that many neurons exhibit post-saccadic spatial preference long after the saccade execution. In addition, dorsal pulvinar lesions lead to gaze-holding deficits expressed as nystagmus or ipsilesional gaze bias, prompting us to investigate the effects of eye position. We tested three starting eye positions (−15°/0°/15°) in monkeys performing a visually-cued memory saccade task. We found two main types of gaze dependence. First, ∼50% of neurons showed an effect of static gaze direction during initial and post-saccadic fixation. Eccentric gaze preference was more common than straight ahead. Some of these neurons were not visually-responsive and might be primarily signaling the position of the eyes in the orbit, or coding foveal targets in a head/body/world-centered reference frame. Second, many neurons showed a combination of eye-centered and gaze-dependent modulation of visual, memory and saccadic responses to a peripheral target. A small subset showed effects consistent with eye position-dependent gain modulation. Analysis of reference frames across task epochs from visual cue to post-saccadic target fixation indicated a transition from predominantly eye-centered encoding to representation of final gaze or foveated locations in non-retinocentric coordinates. These results show that dorsal pulvinar neurons carry information about eye position, which could contribute to steady gaze during postural changes and to reference frame transformations for visually-guided eye and limb movements.New & NoteworthyWork on the pulvinar focused on eye-centered visuospatial representations, but position of the eyes in the orbit is also an important factor that needs to be taken into account during spatial orienting and goal-directed reaching. Here we show that dorsal pulvinar neurons are influenced by eye position. Gaze direction modulated ongoing firing during stable fixation, as well as visual and saccade responses to peripheral targets, suggesting involvement of the dorsal pulvinar in spatial coordinate transformations.

scholarly journals Eye position signals in the dorsal pulvinar during fixation and goal-directed saccades

2020 ◽  
Vol 123 (1) ◽  
pp. 367-391 ◽  
Author(s):  
Lukas Schneider ◽  
Adan-Ulises Dominguez-Vargas ◽  
Lydia Gibson ◽  
Igor Kagan ◽  
Melanie Wilke
Keyword(s):  
Reference Frame ◽  
Visual Memory ◽  
Reference Frames ◽  
Gaze Direction ◽  
Small Subset ◽  
Eye Position ◽  
Position Information ◽  
Cortical Areas ◽  
Perceptual Stability ◽  
Postural Changes

Sensorimotor cortical areas contain eye position information thought to ensure perceptual stability across saccades and underlie spatial transformations supporting goal-directed actions. One pathway by which eye position signals could be relayed to and across cortical areas is via the dorsal pulvinar. Several studies have demonstrated saccade-related activity in the dorsal pulvinar, and we have recently shown that many neurons exhibit postsaccadic spatial preference. In addition, dorsal pulvinar lesions lead to gaze-holding deficits expressed as nystagmus or ipsilesional gaze bias, prompting us to investigate the effects of eye position. We tested three starting eye positions (−15°, 0°, 15°) in monkeys performing a visually cued memory saccade task. We found two main types of gaze dependence. First, ~50% of neurons showed dependence on static gaze direction during initial and postsaccadic fixation, and might be signaling the position of the eyes in the orbit or coding foveal targets in a head/body/world-centered reference frame. The population-derived eye position signal lagged behind the saccade. Second, many neurons showed a combination of eye-centered and gaze-dependent modulation of visual, memory, and saccadic responses to a peripheral target. A small subset showed effects consistent with eye position-dependent gain modulation. Analysis of reference frames across task epochs from visual cue to postsaccadic fixation indicated a transition from predominantly eye-centered encoding to representation of final gaze or foveated locations in nonretinocentric coordinates. These results show that dorsal pulvinar neurons carry information about eye position, which could contribute to steady gaze during postural changes and to reference frame transformations for visually guided eye and limb movements. NEW & NOTEWORTHY Work on the pulvinar focused on eye-centered visuospatial representations, but position of the eyes in the orbit is also an important factor that needs to be taken into account during spatial orienting and goal-directed reaching. We show that dorsal pulvinar neurons are influenced by eye position. Gaze direction modulated ongoing firing during stable fixation, as well as visual and saccade responses to peripheral targets, suggesting involvement of the dorsal pulvinar in spatial coordinate transformations.

scholarly journals Eye movements shape visual learning

2020 ◽  
Vol 117 (14) ◽  
pp. 8203-8211 ◽  
Author(s):  
Pooya Laamerad ◽  
Daniel Guitton ◽  
Christopher C. Pack
Keyword(s):  
Eye Movements ◽  
Visual Processing ◽  
Visual Learning ◽  
Visual Space ◽  
Saccadic Eye Movements ◽  
Spatial Integration ◽  
Perceptual Stability ◽  
Extensive Training ◽  
Visual Tasks ◽  
Saccade Task

Most people easily learn to recognize new faces and places, and with more extensive practice they can become experts at visual tasks as complex as radiological diagnosis and action video games. Such perceptual plasticity has been thoroughly studied in the context of training paradigms that require constant fixation. In contrast, when observers learn under more natural conditions, they make frequent saccadic eye movements. Here we show that such eye movements can play an important role in visual learning. Observers performed a task in which they executed a saccade while discriminating the motion of a cued visual stimulus. Additional stimuli, presented simultaneously with the cued one, permitted an assessment of the perceptual integration of information across visual space. Consistent with previous results on perisaccadic remapping [M. Szinte, D. Jonikaitis, M. Rolfs, P. Cavanagh, H. Deubel,J. Neurophysiol.116, 1592–1602 (2016)], most observers preferentially integrated information from locations representing the presaccadic and postsaccadic retinal positions of the cue. With extensive training on the saccade task, these observers gradually acquired the ability to perform similar motion integration without making eye movements. Importantly, the newly acquired pattern of spatial integration was determined by the metrics of the saccades made during training. These results suggest that oculomotor influences on visual processing, long thought to subserve the function of perceptual stability, also play a role in visual plasticity.

Sign in / Sign up

Export Citation Format

Share Document