The Role of Subcortical Visual Structures in Target Foveation Control

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 291-291
Author(s):  
G I Novikov
Keyword(s):  
Eye Movements ◽  
Visual Target ◽  
Receptive Fields ◽  
Movement Control ◽  
Lateral Geniculate Body ◽  
Electrophysiological Data ◽  
Electrical Microstimulation ◽  
Neuronal Populations

The role of subcortical levels—the lateral geniculate body (LGB) and superior colliculus (SC) of cat—in the control of foveation eye movements is described by a model based on our own electrophysiological data. These data include the characteristics of eye movements elicited by local electrical microstimulation of neuronal structures in the LGB and the SC. The model represents a multilevel system forming the program of foveation eye movements by performing the following actions in temporal sequence: determination of the position of the visual target in retinotopic coordinates, determination of its craniotopic coordinates and determination of the direction and calculation of the velocity of the moving visual target. I discuss algorithms and neuronal mechanisms (including electrophysiological data on single neurons and neuronal populations) of subcortical levels of the cat visual system taking part in foveation eye-movement control for stationary and moving visual objects, as well as the role of directional and orientation properties of receptive fields of subcortical neurons in this control.

scholarly journals Role of Primate Cerebellar Hemisphere in Voluntary Eye Movement Control Revealed by Lesion Effects

2009 ◽  
Vol 101 (2) ◽  
pp. 934-947 ◽  
Author(s):  
Masafumi Ohki ◽  
Hiromasa Kitazawa ◽  
Takahito Hiramatsu ◽  
Kimitake Kaga ◽  
Taiko Kitamura ◽  
...  
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Smooth Pursuit ◽  
Movement Control ◽  
Cerebellar Hemisphere ◽  
Target Velocity ◽  
Eye Movement Control ◽  
Pursuit Eye Movements ◽  
Catch Up

The anatomical connection between the frontal eye field and the cerebellar hemispheric lobule VII (H-VII) suggests a potential role of the hemisphere in voluntary eye movement control. To reveal the involvement of the hemisphere in smooth pursuit and saccade control, we made a unilateral lesion around H-VII and examined its effects in three Macaca fuscata that were trained to pursue visually a small target. To the step (3°)-ramp (5–20°/s) target motion, the monkeys usually showed an initial pursuit eye movement at a latency of 80–140 ms and a small catch-up saccade at 140–220 ms that was followed by a postsaccadic pursuit eye movement that roughly matched the ramp target velocity. After unilateral cerebellar hemispheric lesioning, the initial pursuit eye movements were impaired, and the velocities of the postsaccadic pursuit eye movements decreased. The onsets of 5° visually guided saccades to the stationary target were delayed, and their amplitudes showed a tendency of increased trial-to-trial variability but never became hypo- or hypermetric. Similar tendencies were observed in the onsets and amplitudes of catch-up saccades. The adaptation of open-loop smooth pursuit velocity, tested by a step increase in target velocity for a brief period, was impaired. These lesion effects were recognized in all directions, particularly in the ipsiversive direction. A recovery was observed at 4 wk postlesion for some of these lesion effects. These results suggest that the cerebellar hemispheric region around lobule VII is involved in the control of smooth pursuit and saccadic eye movements.

scholarly journals Simple Configuration Effects on Eye Movements in Horizontal Scanning Tasks

2015 ◽  
Vol 8 (3) ◽  
Author(s):  
Ilze Laicane ◽  
Jurgis Skilters ◽  
Ivars Lacis
Keyword(s):  
Eye Movements ◽  
Perceptual Grouping ◽  
Movement Control ◽  
Oculomotor Control ◽  
Low Level ◽  
Reading Text ◽  
And Shifts ◽  
Meaningful Text ◽  
Gaze Fixations

When reading text, observers alternate periods of stable gaze (fixations) and shifts of gaze (saccades). An important debate in the literature concerns the processes that drive the control of these eye movements. Past studies using strings of letters rather than meaningful text ('z-reading') suggest that eye movement control during reading is, to a large extent, controlled by low-level image properties. These studies, however, have failed to take into account perceptual grouping processes that could drive these low-level effects. We here study the role of various grouping factors in horizontal scanning eye movements, and compare these to reading meaningful text. The results show that sequential horizontal scanning of meaningless and visually distinctive stimuli is slower than for meaningful stimuli (e.g. letters instead of dots). Moreover, we found strong evidence for anticipatory processes in saccadic processing during horizontal scanning tasks. These results suggest a strong role of perceptual grouping in oculomotor control in reading.

scholarly journals Learning to search. The importance of eye movements in the decrease of response times during a visual choice reaction time task

2016 ◽  
Vol 9 (5) ◽  
Author(s):  
Aleksandra Kroll ◽  
Monika Mak ◽  
Jerzy Samochowiec
Keyword(s):  
Eye Movements ◽  
Reaction Time ◽  
Choice Reaction Time ◽  
Visual Target ◽  
Response Times ◽  
Reaction Times ◽  
Reaction Time Task ◽  
Visual Tasks ◽  
Target Searching

Reaction times are often used as an indicator of the efficiency of the processes in thecentral nervous system. While extensive research has been conducted on the possibleresponse time correlates, the role of eye movements in visual tasks is yet unclear. Here wereport data to support the role of eye movements during visual choice reaction time training.Participant performance, reaction times, and total session duration improved. Eyemovementsshowed expected changes in saccade amplitude and resulted in improvementin visual target searching.

scholarly journals Beyond Fixation: detailed characterization of neural selectivity in free-viewing primates

2021 ◽  
Author(s):  
Jacob L Yates ◽  
Shanna H Coop ◽  
Gabriel H Sarch ◽  
Ruei-Jr Wu ◽  
Daniel A Butts ◽  
...  
Keyword(s):  
Eye Movements ◽  
Receptive Fields ◽  
Natural Behavior ◽  
Visual Neurons ◽  
Trained Subjects ◽  
V1 Neurons ◽  
Fixational Eye Movements ◽  
Neural Selectivity

Virtually all vision studies use a fixation point to stabilize gaze, rendering stimuli on video screens fixed to retinal coordinates. This approach requires trained subjects, is limited by the accuracy of fixational eye movements, and ignores the role of eye movements in shaping visual input. To overcome these limitations, we developed a suite of hardware and software tools to study vision during natural behavior in untrained subjects. We show this approach recovers receptive fields and tuning properties of visual neurons from multiple cortical areas of marmoset monkeys. Combined with high-precision eye-tracking, it achieves sufficient resolution to recover the receptive fields of foveal V1 neurons. These findings demonstrate the power of this approach for characterizing neural response while simultaneously studying the dynamics of natural behavior.

The Role of Eye Movements in the Perception of the Horizontal—Vertical Illusion

Perception ◽  
1974 ◽  
Vol 3 (1) ◽  
pp. 49-52 ◽  
Author(s):  
H R Schiffman ◽  
J Thompson
Keyword(s):  
Eye Movements ◽  
Major Result ◽  
Secondary Role

An experiment examining the role of eye movements in the determination of magnitude of the horizontal—vertical illusion (HVI) was performed by presenting the stimulus figures in conditions where eye movements or tendencies to eye movements were eliminated (i.e. presenting small figures tachistoscopically). The major result was that the illusion occurred within these conditions, indicating that eye movements do not play a major role in the production of the HVI. However, the finding that the magnitude of the HVI was positively affected in the conditions where tendencies to make eye movements were possible suggests that they exert a secondary role.

scholarly journals Motor learning by selection in visual working memory

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ilja Wagner ◽  
Christian Wolf ◽  
Alexander C. Schütz
Keyword(s):  
Working Memory ◽  
Eye Movements ◽  
Visual Working Memory ◽  
Movement Control ◽  
Saccadic Eye Movements ◽  
Neural Basis ◽  
Temporal Window ◽  
Optimal Movement ◽  
Saccade Adaptation

AbstractMotor adaptation maintains movement accuracy over the lifetime. Saccadic eye movements have been used successfully to study the mechanisms and neural basis of adaptation. Using behaviorally irrelevant targets, it has been shown that saccade adaptation is driven by errors only in a brief temporal interval after movement completion. However, under natural conditions, eye movements are used to extract information from behaviorally relevant objects and to guide actions manipulating these objects. In this case, the action outcome often becomes apparent only long after movement completion, outside the supposed temporal window of error evaluation. Here, we show that saccade adaptation can be driven by error signals long after the movement when using behaviorally relevant targets. Adaptation occurred when a task-relevant target appeared two seconds after the saccade, or when a retro-cue indicated which of two targets, stored in visual working memory, was task-relevant. Our results emphasize the important role of visual working memory for optimal movement control.

scholarly journals Edge Detection Model Based on Involuntary Tremors and Drifts of the Eye

2007 ◽  
Vol 11 (6) ◽  
pp. 648-654 ◽  
Author(s):  
András Róka ◽  
◽  
Ádám Csapó ◽  
Barna Reskó ◽  
Péter Baranyi
Keyword(s):  
Eye Movements ◽  
Edge Detection ◽  
Ganglion Cells ◽  
Dynamic Properties ◽  
Receptive Fields ◽  
Detection Algorithm ◽  
Point Of View ◽  
Detection Model ◽  
Detection Algorithms

Recent results in retinal research have shown that ganglion cell receptive fields cover the mammalian retina in a mosaic arrangement, with insignificant amounts of overlap in the central fovea. This means that the biological relevance of traditional and widely adapted edge-detection algorithms with convolution-based overlapping operator architectures has been disproved. However, using traditional filters with non-overlapping operator architectures leads to considerable losses in contour information. This paper introduces a novel, tremor- and drift-based edge-detection algorithm that reconciles these differences between the physiology of the retina and the overlapping architectures used by today’s widely adapted algorithms. The algorithm takes into consideration data convergence, as well as the dynamic properties of the retina, by incorporating a model of involuntary eye tremors and drifts and the impulse responses of ganglion cells. Based on the evaluation of the model, two hypotheses are formulated on the highly debated role of involuntary eye tremors: 1) The role of involuntary eye movements has information theoretical implications 2) From an information processing point of view, the functional role of involuntary eye movements extends to more than just the maintenance of action potentials. Involuntary eye-movements may be responsible for the compensation of information losses caused by a non-overlapping receptive field architecture.

A Ring Model for Direction-Selective Simple Cells in the Visual Cortex

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 164-164
Author(s):  
T Hamada ◽  
K Kato ◽  
M Yamashima
Keyword(s):  
Visual Cortex ◽  
Experimental Studies ◽  
Receptive Fields ◽  
Lateral Geniculate Body ◽  
Neural Model ◽  
Cortical Cells ◽  
Simple Cells ◽  
Ring Model ◽  
Gabor Functions

Experimental studies have shown that (1) direction-selective simple cells in the visual cortex have spatiotemporally inseparable receptive fields, whose spatial profiles at a given time are described by Gabor functions: a sinusoid multiplied by a Gaussian, with a phase parameter; (2) among simple cells, the phases are distributed not merely at 0 and pi/2 as for sine and cosine Gabor functions, but uniformly between 0 and 2pi (DeAngelis et al, 1993 Journal of Neurophysiology69 1091 – 1117); (3) anatomically, these simple cells receive inputs more from other cortical cells than from the lateral geniculate body (LGN) (Ahmed et al, 1994 Journal of Comparative Neurology341 39 – 49). We accordingly propose here a neural model for the simple cells whose receptive fields are assumed to be of the same spatial position and orientation. In the model, several cortical cells are arranged in a ring with mutual excitatory and inhibitory connections, and receive afferent signals from lagged and nonlagged cells in LGN (Saul and Humphrey, 1990 Journal of Neurophysiology64 206 – 224). Computer simulation shows that the cortical cells have spatiotemporally inseparable receptive fields with spatial profiles described by Gabor functions, and are directionally selective to a moving grating. The cells are found to be arranged so that their Gabor phases vary regularly from 0 to 2pi with rotation along the ring. The connection among the cortical cells has a role of amplification as in the canonical microcircuit model (Douglas et al, 1989 Neural Computation1 480 – 488).

Decorrelation of neural activity during fixational instability: Possible implications for the refinement of V1 receptive fields

2004 ◽  
Vol 21 (5) ◽  
pp. 725-738 ◽  
Author(s):  
MICHELE RUCCI ◽  
ANTONINO CASILE
Keyword(s):  
Eye Movements ◽  
Neural Activity ◽  
Receptive Fields ◽  
Natural Scenes ◽  
Neural Responses ◽  
Response Characteristics ◽  
Neuronal Populations ◽  
Fixational Eye Movements ◽  
Eye Opening ◽  
Oculomotor Activity

Early in life, visual experience appears to influence the refinement and maintenance of the orientation-selective responses of neurons in the primary visual cortex. After eye opening, the statistical structure of visually driven neural responses depends not only on the stimulus, but also on how the stimulus is scanned during behavior. Modulations of neural activity due to behavior may thus play a role in the experience-dependent refinement of cell response characteristics. To investigate the possible influences of eye movements on the maturation of thalamocortical connectivity, we have simulated the responses of neuronal populations in the lateral geniculate nucleus (LGN) and V1 of the cat while images of natural scenes were scanned in a way that replicated the cat's oculomotor activity. In the model, fixational eye movements were essential to attenuate neural sensitivity to the broad correlational structure of natural visual input, decorrelate neural responses, and establish a regime of neural activity that was compatible with a Hebbian segregation of geniculate afferents to the cortex. We show that this result is highly robust and does not depend on the precise characteristics of the model.

Facilitation of Smooth Pursuit Initiation by Electrical Stimulation in the Supplementary Eye Fields

2001 ◽  
Vol 86 (5) ◽  
pp. 2413-2425 ◽  
Author(s):  
M. Missal ◽  
S. J. Heinen
Keyword(s):  
Electrical Stimulation ◽  
Eye Movements ◽  
Smooth Pursuit ◽  
Electrical Microstimulation ◽  
Pursuit Initiation ◽  
Fixation Task ◽  
Catch Up ◽  
Eye Velocity ◽  
Supplementary Eye Fields

The role of the supplementary eye fields (SEF) during smooth pursuit was investigated with electrical microstimulation. We found that stimulation in the SEF increased the acceleration and velocity of the eyes in the direction of target motion during smooth pursuit initiation but not during sustained pursuit. The increase in eye velocity during initiation will be referred to as pursuit facilitation and was observed at sites where saccades could not be evoked with the same stimulation parameters. On average, electrical stimulation increased eye velocity by ∼20%. At most sites, the threshold for a significant facilitation was 50 μA with a stimulation frequency of 300 Hz. Facilitation of pursuit initiation depended on the timing of stimulation trains. The effect was most pronounced if the stimulation was delivered before smooth pursuit initiation. On average, eye velocity in stimulation trials increased linearly as a function of eye velocity in control trials, and this function had a slope greater than one, suggesting a multiplicative influence of the stimulation. Stimulation during a fixation task did not evoke smooth eye movements. The latency of catch-up saccades was increased during facilitation, but their accuracy was not affected. Saccades toward stationary targets were not affected by the stimulation. The results are further evidence that the SEF plays a role in smooth pursuit in addition to its known role in saccade planning and suggest that this role may be to control the gain of smooth pursuit during initiation. The covariance between pursuit facilitation and the timing of the catch-up saccade as a result of stimulation suggests that these different eye movements systems are coordinated to achieve a common goal.

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