Oculomotor Tracking in Two Dimensions

1999 ◽  
Vol 81 (4) ◽  
pp. 1597-1602 ◽  
Author(s):  
Kevin C. Engel ◽  
John H. Anderson ◽  
John F. Soechting
Keyword(s):  
Smooth Pursuit ◽  
Target Location ◽  
Two Dimensions ◽  
Positional Error ◽  
Additional Insight ◽  
Saccade Onset ◽  
Straight Line ◽  
Average Slope ◽  
Pursuit Movement ◽  
Pursuit Velocity

Oculomotor tracking in two dimensions. Results from studies of oculomotor tracking in one dimension have indicated that saccades are driven primarily by errors in position, whereas smooth pursuit movements are driven primarily by errors in velocity. To test whether this result generalizes to two-dimensional tracking, we asked subjects to track a target that moved initially in a straight line then changed direction. We found that the general premise does indeed hold true; however, the study of oculomotor tracking in two dimensions provides additional insight. The first saccade was directed slightly in advance of target location at saccade onset. Thus its direction was related primarily to angular positional error. The direction of the smooth pursuit movement after the saccade was related linearly to the direction of target motion with an average slope of 0.8. Furthermore the magnitude and direction of smooth pursuit velocity did not change abruptly; consequently the direction of smooth pursuit appeared to rotate smoothly over time.

Perisaccadic Mislocalization of Visual Targets by Head-Free Gaze Shifts: Visual or Motor?

2008 ◽  
Vol 100 (4) ◽  
pp. 1848-1867 ◽  
Author(s):  
Sigrid M. C. I. van Wetter ◽  
A. John van Opstal
Keyword(s):  
Target Location ◽  
Saccadic Eye Movements ◽  
Open Loop ◽  
Spatial Updating ◽  
Gaze Shifts ◽  
Gaze Shift ◽  
The Gaze ◽  
Visual Probe ◽  
Saccade Onset ◽  
Saccade Direction

Such perisaccadic mislocalization is maximal in the direction of the saccade and varies systematically with the target-saccade onset delay. We have recently shown that under head-fixed conditions perisaccadic errors do not follow the quantitative predictions of current visuomotor models that explain these mislocalizations in terms of spatial updating. These models all assume sluggish eye-movement feedback and therefore predict that errors should vary systematically with the amplitude and kinematics of the intervening saccade. Instead, we reported that errors depend only weakly on the saccade amplitude. An alternative explanation for the data is that around the saccade the perceived target location undergoes a uniform transient shift in the saccade direction, but that the oculomotor feedback is, on average, accurate. This “ visual shift” hypothesis predicts that errors will also remain insensitive to kinematic variability within much larger head-free gaze shifts. Here we test this prediction by presenting a brief visual probe near the onset of gaze saccades between 40 and 70° amplitude. According to models with inaccurate gaze-motor feedback, the expected perisaccadic errors for such gaze shifts should be as large as 30° and depend heavily on the kinematics of the gaze shift. In contrast, we found that the actual peak errors were similar to those reported for much smaller saccadic eye movements, i.e., on average about 10°, and that neither gaze-shift amplitude nor kinematics plays a systematic role. Our data further corroborate the visual origin of perisaccadic mislocalization under open-loop conditions and strengthen the idea that efferent feedback signals in the gaze-control system are fast and accurate.

scholarly journals Saccades and smooth pursuit eye movements trigger equivalent gaze-cued orienting effects

2018 ◽  
Vol 71 (9) ◽  
pp. 1860-1872 ◽  
Author(s):  
Stephen RH Langton ◽  
Alex H McIntyre ◽  
Peter JB Hancock ◽  
Helmut Leder
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Target Location ◽  
Eye Gaze ◽  
Saccadic Eye Movements ◽  
Gaze Shift ◽  
The Gaze ◽  
Orienting Effect ◽  
Motion Speed ◽  
Uncued Target

Research has established that a perceived eye gaze produces a concomitant shift in a viewer’s spatial attention in the direction of that gaze. The two experiments reported here investigate the extent to which the nature of the eye movement made by the gazer contributes to this orienting effect. On each trial in these experiments, participants were asked to make a speeded response to a target that could appear in a location toward which a centrally presented face had just gazed (a cued target) or in a location that was not the recipient of a gaze (an uncued target). The gaze cues consisted of either fast saccadic eye movements or slower smooth pursuit movements. Cued targets were responded to faster than uncued targets, and this gaze-cued orienting effect was found to be equivalent for each type of gaze shift both when the gazes were un-predictive of target location (Experiment 1) and counterpredictive of target location (Experiment 2). The results offer no support for the hypothesis that motion speed modulates gaze-cued orienting. However, they do suggest that motion of the eyes per se, regardless of the type of movement, may be sufficient to trigger an orienting effect.

Mapping with Monocular Vision in Two Dimensions

2010 ◽  
Vol 1 (4) ◽  
pp. 56-65 ◽  
Author(s):  
Nicolau Leal Werneck ◽  
Anna Helena Reali Costa
Keyword(s):  
Optical Axis ◽  
Two Dimensions ◽  
Obstacle Detection ◽  
Uniform Motion ◽  
Mapping Algorithms ◽  
Multiple Images ◽  
Line Segments ◽  
Straight Line ◽  
Camera Intrinsic Parameters ◽  
Over Time

This article presents the problem of building bi-dimensional maps of environments when the sensor available is a camera used to detect edges crossing a single line of pixels and motion is restricted to a straight line along the optical axis. The position over time must be provided or assumed. Mapping algorithms for these conditions can be built with the landmark parameters estimated from sets of matched detection from multiple images. This article shows how maps that are correctly up to scale can be built without knowledge of the camera intrinsic parameters or speed during uniform motion, and how performing an inverse parameterization of the image coordinates turns the mapping problem into the fitting of line segments to a group of points. The resulting technique is a simplified form of visual SLAM that can be better suited for applications such as obstacle detection in mobile robots.

Activity of Mesencephalic Vertical Burst Neurons During Saccades and Smooth Pursuit

2000 ◽  
Vol 83 (4) ◽  
pp. 2080-2092 ◽  
Author(s):  
M. Missal ◽  
S. de Brouwer ◽  
P. Lefèvre ◽  
E. Olivier
Keyword(s):  
Vertical Velocity ◽  
Smooth Pursuit ◽  
Medial Longitudinal Fasciculus ◽  
Eye Position ◽  
Interstitial Nucleus Of Cajal ◽  
Burst Neurons ◽  
Preferred Direction ◽  
Saccade Onset ◽  
Vertical Saccades ◽  
Eye Velocity

The activity of vertical burst neurons (BNs) was recorded in the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF-BNs) and in the interstitial nucleus of Cajal (NIC-BNs) in head-restrained cats while performing saccades or smooth pursuit. BNs emitted a high-frequency burst of action potentials before and during vertical saccades. On average, these bursts led saccade onset by 14 ± 4 ms (mean ± SD, n = 23), and this value was in the range of latencies (∼5–15 ms) of medium-lead burst neurons (MLBNs). All NIC-BNs ( n = 15) had a downward preferred direction, whereas riMLF-BNs showed either a downward ( n = 3) or an upward ( n = 5) preferred direction. We found significant correlations between saccade and burst parameters in all BNs: vertical amplitude was correlated with the number of spikes, maximum vertical velocity with maximum of the spike density, and saccade duration with burst duration. A correlation was also found between instantaneous vertical velocity and neuronal activity during saccades. During fixation, all riMLF-BNs and ∼50% of NIC-BNs (7/15) were silent. Among NIC-BNs active during fixation (8/15), only two cells had an activity correlated with the eye position in the orbit. During smooth pursuit, most riMLF-BNs were silent (7/8), but all NIC-BNs showed an activity that was significantly correlated with the eye velocity. This activity was unaltered during temporary disappearance of the visual target, demonstrating that it was not visual in origin. For a given neuron, its on-direction during smooth pursuit and saccades remained identical. The activity of NIC-BNs during both saccades and smooth pursuit can be described by a nonlinear exponential function using the velocity of the eye as independent variable. We suggest that riMLF-BNs, which were not active during smooth pursuit, are vertical MLBNs responsible for the generation of vertical saccades. Because NIC-BNs discharged during both saccades and pursuit, they cannot be regarded as MLBNs as usually defined. NIC-BNs could, however, be the site of convergence of both the saccadic and smooth pursuit signals at the premotoneuronal level. Alternatively, NIC-BNs could participate in the integration of eye velocity to eye position signals and represent input neurons to a common integrator.

Effects of Learning on Smooth Pursuit During Transient Disappearance of a Visual Target

2003 ◽  
Vol 90 (2) ◽  
pp. 972-982 ◽  
Author(s):  
Laurent Madelain ◽  
Richard J. Krauzlis
Keyword(s):  
Smooth Pursuit ◽  
Visual Target ◽  
Visual Signals ◽  
Control Group ◽  
Long Term Effects ◽  
Velocity Gain ◽  
Visual Inputs ◽  
Before And After ◽  
Pursuit Velocity

Previous research has demonstrated learning in the pursuit system, but it is unclear whether these effects are the result of changes in visual or motor processing. The ability to maintain smooth pursuit during the transient disappearance of a visual target provides a way to assess pursuit properties in the absence of visual inputs. To study the long-term effects of learning on nonvisual signals for pursuit, we used an operant conditioning procedure. By providing a reinforcing auditory stimulus during periods of accurate tracking, we increased the pursuit velocity gain during target blanking from 0.59 in the baseline session to 0.89 after 8 to 10 daily sessions of training. Learning also reduced the occurrence of saccades. The learned effects generalized to untrained target velocities and persisted in the presence of a textured visual background. In a yoked-control group, the reinforcer was independent of the subjects' responses, and the velocity gain remained unchanged (from 0.6 to 0.63, respectively, before and after training). In a control group that received no reinforcer, gain increased slightly after repetition of the task (from 0.63 to 0.71, respectively, before and after training). Using a model of pursuit, we show that these effects of learning can be simulated by modifying the gain of an extra-retinal signal. Our results demonstrate that learned contingencies can increase eye velocity in the absence of visual signals and support the view that pursuit is regulated by extra-retinal signals that can undergo long-term plasticity.

Voluntary control of smooth pursuit velocity

1969 ◽  
Vol 9 (9) ◽  
pp. 1167-1171 ◽  
Author(s):  
Robert M. Steinman ◽  
Alexander A. Skavenski ◽  
Richard V. Sansbury
Keyword(s):  
Smooth Pursuit ◽  
Voluntary Control ◽  
Pursuit Velocity

Determination of Trackball and End Effector Diameters in Laparoscopic Tools

2005 ◽  
Vol 49 (18) ◽  
pp. 1710-1713
Author(s):  
A.E. Trejo ◽  
M.-C. Jung ◽  
M.S. Hallbeck
Keyword(s):  
Target Location ◽  
Target Position ◽  
Initial Position ◽  
End Effector ◽  
Independent Variables ◽  
Straight Line ◽  
Left And Right ◽  
Time Accuracy ◽  
Laparoscopic Tools

As part of a continuous effort of reaching the optimal use of the intuitool, a study was conducted to identify the optimal diameter combination between the trackball and the end effector ball. The task was to simulate the end effector movement during an operation, using different diameter combinations. Twenty students performed the trackball-controlling tasks to move the end effector from an initial position to designated circular-shaped targets. The trackball diameters were 19 mm and 40 mm, and those of the end effector balls were 3 mm, 5 mm, and 10 mm. There were four targets: right, left, up, and down. Travel time, accuracy, and trail deviation were measured as independent variables. Accuracy was not a significant factor showing that all participants followed instructions to reach each target as accurately as possible. The time to reach the target depended both on target location and trackball to end effector ratio individually and in their interaction. It was quickest to get to the upper target compared to all other locations. Trial deviation depended only on the target position and the target location and ratio interaction. The performance of going in a straight line was best for the left and right directions as opposed to up and down using the trackball.

The upper limit of human smooth pursuit velocity

1985 ◽  
Vol 25 (4) ◽  
pp. 561-563 ◽  
Author(s):  
Craig H. Meyer ◽  
Adrian G. Lasker ◽  
David A. Robinson
Keyword(s):  
Smooth Pursuit ◽  
Upper Limit ◽  
Pursuit Velocity

scholarly journals Similar prevalence and magnitude of auditory-evoked and visually evoked activity in the frontal eye fields: implications for multisensory motor control

2016 ◽  
Vol 115 (6) ◽  
pp. 3162-3173 ◽  
Author(s):  
Valeria C. Caruso ◽  
Daniel S. Pages ◽  
Marc A. Sommer ◽  
Jennifer M. Groh
Keyword(s):  
Target Location ◽  
Saccadic Eye Movements ◽  
Motor Output ◽  
Visual Signals ◽  
Frontal Eye Fields ◽  
Activity Levels ◽  
Population Activity ◽  
Movement Vector ◽  
Saccade Onset ◽  
Evoked Activity

Saccadic eye movements can be elicited by more than one type of sensory stimulus. This implies substantial transformations of signals originating in different sense organs as they reach a common motor output pathway. In this study, we compared the prevalence and magnitude of auditory- and visually evoked activity in a structure implicated in oculomotor processing, the primate frontal eye fields (FEF). We recorded from 324 single neurons while 2 monkeys performed delayed saccades to visual or auditory targets. We found that 64% of FEF neurons were active on presentation of auditory targets and 87% were active during auditory-guided saccades, compared with 75 and 84% for visual targets and saccades. As saccade onset approached, the average level of population activity in the FEF became indistinguishable on visual and auditory trials. FEF activity was better correlated with the movement vector than with the target location for both modalities. In summary, the large proportion of auditory-responsive neurons in the FEF, the similarity between visual and auditory activity levels at the time of the saccade, and the strong correlation between the activity and the saccade vector suggest that auditory signals undergo tailoring to match roughly the strength of visual signals present in the FEF, facilitating accessing of a common motor output pathway.

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