scholarly journals Saccadic eye movements are coordinated with head movements in walking chickens

1982 ◽  
Vol 97 (1) ◽  
pp. 217-223
Author(s):  
D. W. Pratt
Keyword(s):  
Eye Movements ◽  
Saccadic Eye Movements ◽  
Head Movements ◽  
Clear Vision ◽  
Head Bobbing ◽  
Insufficient Time ◽  
Made In

1. Saccadic eye movements during walking were studied in chickens using cinematography. 2. Saccades were made during about 80% of the thrust phases of head bobbing, and not made in the hold phases. 3. The coordination of saccades with head movements maintains clear vision for the largest possible proportion of the time. 4. The absence of saccades in hold phases and in some thrusts is probably not the result of insufficient time to organize a saccade.

scholarly journals Coupling Between Horizontal and Vertical Components of Saccadic Eye Movements During Constant Amplitude and Direction Gaze Shifts in the Rhesus Monkey

2008 ◽  
Vol 100 (6) ◽  
pp. 3375-3393 ◽  
Author(s):  
Edward G. Freedman
Keyword(s):  
Eye Movements ◽  
Saccadic Eye Movements ◽  
Head Movements ◽  
Horizontal Meridian ◽  
Constant Amplitude ◽  
Saccade Amplitude ◽  
Gaze Shifts ◽  
Horizontal Saccade ◽  
Vertical Saccade ◽  
Saccade Duration

When the head is free to move, changes in the direction of the line of sight (gaze shifts) can be accomplished using coordinated movements of the eyes and head. During repeated gaze shifts between the same two targets, the amplitudes of the saccadic eye movements and movements of the head vary inversely as a function of the starting positions of the eyes in the orbits. In addition, as head-movement amplitudes and velocities increase, saccade velocities decline. Taken together these observations lead to a reversal in the expected correlation between saccade duration and amplitude: small-amplitude saccades associated with large head movements can have longer durations than larger-amplitude saccades associated with small head movements. The data in this report indicate that this reversal occurs during gaze shifts along the horizontal meridian and also when considering the horizontal component of oblique saccades made when the eyes begin deviated only along the horizontal meridian. Under these conditions, it is possible to determine whether the variability in the duration of the constant amplitude vertical component of oblique saccades is accounted for better by increases in horizontal saccade amplitude or increases in horizontal saccade duration. Results show that vertical saccade duration can be inversely related to horizontal saccade amplitude (or unrelated to it) but that horizontal saccade duration is an excellent predictor of vertical saccade duration. Modifications to existing hypotheses of gaze control are assessed based on these new observations and a mechanism is proposed that can account for these data.

Properties of signals that determine the amplitude and direction of saccadic eye movements in monkeys

1986 ◽  
Vol 56 (1) ◽  
pp. 196-207 ◽  
Author(s):  
A. McKenzie ◽  
S. G. Lisberger
Keyword(s):  
Eye Movements ◽  
Saccadic Eye Movements ◽  
Head Movements ◽  
Polar Coordinates ◽  
Eye Position ◽  
Spatial Error ◽  
Internal Feedback ◽  
The Neural Network ◽  
Smooth Change ◽  
Highly Correlated

Monkeys were trained to make saccades to briefly flashed targets. We presented the flash during smooth pursuit of another target, so that there was a smooth change in eye position after the flash. We could then determine whether the flash-evoked saccades compensated for the intervening smooth eye movements to point the eyes at the position of the flash in space. We defined the "retinal error" as the vector from the position of the eye at the time of the flash to the position of the target. We defined "spatial error" as the vector from the position of the eye at the time of the saccade to the position of the flashed target in space. The direction of the saccade (in polar coordinates) was more highly correlated with the direction of the retinal error than with the direction of the spatial error. Saccade amplitude was also better correlated with the amplitude of the retinal error. We obtained the same results whether the flash was presented during pursuit with the head fixed or during pursuit with combined eye-head movements. Statistical analysis demonstrated that the direction of the saccade was determined only by the retinal error in two of the three monkeys. In the third monkey saccade direction was determined primarily by retinal error but had a consistent bias toward spatial error. The bias can be attributed to this monkey's earlier practice in which the flashed target was reilluminated so he could ultimately make a saccade to the correct position in space. These data suggest that the saccade generator does not normally use nonvisual feedback about smooth changes in eye or gaze position. In two monkeys we also provided sequential target flashes during pursuit with the second flash timed so that it occurred just before the first saccade. As above, the first saccade was appropriate for the retinal error provided by the first flash. The second saccade compensated for the first and pointed the eyes at the position of the second target in space. We conclude, as others have before (12, 21), that the saccade generator receives feedback about its own output, saccades. Our results require revision of existing models of the neural network that generates saccades. We suggest two models that retain the use of internal feedback suggested by others. We favor a model that accounts for our data by assuming that internal feedback originates directly from the output of the saccade generator and reports only saccadic changes in eye position.

Visual-Vestibular Interaction with Telescopic Spectacles

1991 ◽  
Vol 1 (3) ◽  
pp. 263-277 ◽  
Author(s):  
J.L. Demer ◽  
J. Goldberg ◽  
F.I. Porter ◽  
H.A. Jenkins ◽  
K. Schmidt
Keyword(s):  
Eye Movements ◽  
Retinal Image ◽  
Head Rotation ◽  
Normal Subjects ◽  
Head Movements ◽  
Head Velocity ◽  
Ocular Reflex ◽  
Clear Vision ◽  
Visual Vestibular Interaction ◽  
Vestibulo Ocular Reflex

Vestibularly and visually driven eye movements interact to compensate for head movements to maintain the necessary retinal image stability for clear vision. The wearing of highly magnifying telescopic spectacles requires that such compensatory visual-vestibular interaction operate in a quantitative regime much more demanding than that normally encountered. We employed electro-oculography to investigate the effect of wearing of 2×, 4×, and 6× binocular telescopic spectacles on visual-vestibular interactions during sinusoidal head rotation in 43 normal subjects. All telescopic spectacle powers produced a large, immediate increase in the gain (eye velocity/head velocity) of compensatory eye movements, called the visual-vestibulo-ocular reflex (VVOR). However, the amount of VVOR gain augmentation became limited as spectacle magnification and the amplitude of head velocity increased. Optokinetic responses during wearing of telescopic spectacles exhibited a similar nonlinearity with respect to stimulus amplitude and spectacle magnification. Computer simulation was used to demonstrate that the nonlinear response of the VVOR with telescopic spectacles is a result of nonlinearities in visually guided tracking movements. Immediate augmentation of VVOR gain by telescopic spectacles declined significantly with increasing age in the subject pool studied. Presentation of unmagnified visual field peripheral to the telescopic spectacles reduced the immediate VVOR gain-enhancing effect of central magnified vision. These results imply that the VVOR may not be adequate to maintain retinal image stability during head movements when strongly magnifying telescopic spectacles are worn.

Subcortical contributions to head movements in macaques. I. Contrasting effects of electrical stimulation of a medial pontomedullary region and the superior colliculus

1994 ◽  
Vol 72 (6) ◽  
pp. 2648-2664 ◽  
Author(s):  
R. J. Cowie ◽  
D. L. Robinson
Keyword(s):  
Electrical Stimulation ◽  
Eye Movements ◽  
Superior Colliculus ◽  
Head Movement ◽  
Saccadic Eye Movements ◽  
Head Movements ◽  
Reticular Nucleus ◽  
Gaze Shifts ◽  
Gigantocellular Reticular Nucleus ◽  
External Events

1. These studies were initiated to understand the neural sites and mechanisms controlling head movements during gaze shifts. Gaze shifts are made by saccadic eye movements with and without head movements. Sites were stimulated electrically within the brain stem of awake, trained monkeys relatively free to make head movements to study the head-movement components of gaze shifts. 2. Electrical stimulation in and around the gigantocellular reticular nucleus evoked head movements in the ipsilateral direction. Gaze shifts were never evoked from these sites, presumably because the vestibulo-ocular reflex compensated. The rough topography of this region included large head movements laterally, small movements medially, downward movements from dorsal sites, and upward movements more ventrally. 3. The initial position of the head influenced the magnitude of the elicited movement with larger movements produced when the head was directed to the contralateral side. Attentive fixation was associated with larger and faster head movements when compared with those evoked during spontaneous behavior. 4. The superior colliculus makes a significant contribution to gaze shifts and has been shown to contribute to head movements. Because the colliculus is a major source of afferents to the gigantocellular reticular nucleus, comparable stimulation studies of the superior colliculus were conducted. When the colliculus was excited, shifts of gaze in the contralateral direction were predominant. These were most often accomplished by saccadic eye movements, however, we frequently elicited head movements that had an average latency 10 ms longer than those elicited from the reticular head movement region. Sites evoking head movements tended to be deeper and more caudal than loci eliciting eye movements. Neither the onset latencies, amplitudes, nor peak velocities of head movements and eye movements were correlated. Gaze shifts evoked from the caudal colliculus with the head free were larger than those elicited from the same site with the head fixed. 5. These studies demonstrate that both the superior colliculus and gigantocellular reticular nucleus mediate head movements. The colliculus plays a role in orienting to external events, and so collicular head movements predominantly were associated with gaze shifts, with the eye and head movements uncoupled. The medullary reticular system may play a role in the integration of a wider range of movements. Head movements from the medullary reticular sites probably participate in several forms of head movements, such as those that are related to postural reflexes, started volitionally, and/or oriented to external events.

A Survey of Eye Movements

2015 ◽  
pp. 1-23 ◽  
Author(s):  
R. John Leigh ◽  
David S. Zee
Keyword(s):  
Eye Movements ◽  
Experimental Design ◽  
Motor Learning ◽  
Functional Imaging ◽  
Head Movements ◽  
Line Of Sight ◽  
Clear Vision ◽  
Neural Substrate ◽  
Gaze Holding ◽  
The Relationship

This chapter reviews the visual requirements, properties, and neural substrate of eye movements and the advantages they offer to clinicians and scientists. Eye movements are easily observed, measured, and classified by the way they serve vision. The relationship between eye rotations and extraocular motoneuron discharge is approximately linear, making it possible to study how networks of neurons temporally integrate raw sensory signals. Gaze-holding vestibular eye movements act at short latency to guarantee clear vision during natural head movements. Gaze-shifting saccades, pursuit, and vergence movements are concerned with pointing each eye’s line of sight (fovea) at features of interest in the environment. By combining ingenious experimental design with functional imaging and electrophysiology, it has become possible to understand much about the neural substrate underlying each class of eye movements. Consequently, eye movements have become powerful tools to study cognition and memory, adaptation and motor learning, as well as aiding topological diagnosis.

Luxotonic responses of units in macaque striate cortex

1979 ◽  
Vol 42 (6) ◽  
pp. 1495-1517 ◽  
Author(s):  
Y. Kayama ◽  
R. R. Riso ◽  
J. R. Bartlett ◽  
R. W. Doty
Keyword(s):  
Eye Movements ◽  
Lateral Geniculate Nucleus ◽  
Striate Cortex ◽  
Ganglion Cells ◽  
Saccadic Eye Movements ◽  
Similar Response ◽  
Retinal Ganglion ◽  
Lateral Geniculate ◽  
The Face ◽  
Made In

1. Single units in striate cortex were studied in alert macaques while they viewed a ganzfeld. Of the 385 well-isolated units studied for 10 min to 2 h, 24% gave "luxotonic" responses, i.e., their rate of discharge for 1 min or more in diffuse, featureless, wideangle illumination (20-450 cd/m2) was at least double that during a comparable period in darkness, or vice versa, and not attributable to eye movements of blinking. Those discharging faster in the light, "photergic" units, outnumber those responding to darkness, "scotergic" units 1 by 4:1. 2. In the lateral geniculate nucleus, on the other hand, among 46 units studied, 28% were luxotonic, but scotergic units were the more common. Both types were present in both magno- and parvocellular laminae. 3. For striate cortex two-thirds of the luxotonic units were binocular. Some showed highly similar response for either eye alone, and essentially no summation binocularly; others had grossly differing responses from each eye, and complex binocular interaction. 4. Many units of all types at striate cortex showed significant modulation of their activity consequent to saccadic eye movements made in darkness, whereas comparable modulation was not observed at the lateral geniculate nucleus. 5. On the basis of these and other findings it is concluded that luxotonic cortical activity is prominent probably only in alert primates, and that this is a consequence of the fact that all retinal ganglion cells in primates synapse in the lateral geniculate nucleus (Ref. 9). Possible functions range from mere trophic input to providing a veridical image or a scaling factor for maintenance of perceptual constancy in the face of varying levels of general illumination.

Saccadic Eye Movements and Eye-Head Coordination in Children

1977 ◽  
Vol 44 (2) ◽  
pp. 599-610 ◽  
Author(s):  
Cynthia J. Funk ◽  
Marjorie E. Anderson
Keyword(s):  
Eye Movements ◽  
Movement Control ◽  
Saccadic Eye Movements ◽  
Head Movements ◽  
Reading Levels ◽  
Quantitative Measurements ◽  
Temporal And Spatial ◽  
Developmental Characteristics ◽  
Coordination Patterns ◽  
The Relationship

The eye and head movements of nine children, ages 6 through 10, were measured in order to establish quantitative characteristics of eye movements and eye-head coordination patterns of children with normal vision and reading levels. The relationship between saccade amplitude and duration was linear, but the slope of this relationship indicated that saccades in children may have higher velocities than they do in adults. One of three temporal patterns of head and saccadic eye movement occurred during shifts of gaze to visual targets, depending on the temporal and spatial predictability of the target. It is suggested that quantitative measurements such as these could be used to examine developmental characteristics of eye and eye-head movement control.

Contribution of the Frontal Eye Field to Gaze Shifts in the Head-Unrestrained Monkey: Effects of Microstimulation

2007 ◽  
Vol 97 (1) ◽  
pp. 618-634 ◽  
Author(s):  
Thomas A. Knight ◽  
Albert F. Fuchs
Keyword(s):  
Eye Movements ◽  
Stimulus Duration ◽  
Head Movement ◽  
Saccadic Eye Movements ◽  
Head Movements ◽  
Frontal Eye Field ◽  
Threshold Region ◽  
Gaze Shifts ◽  
Eye Field ◽  
Orbital Position

The role of the primate frontal eye field (FEF) has been inferred primarily from experiments investigating saccadic eye movements with the head restrained. Three recent reports investigating head-unrestrained gaze shifts disagree on whether head movements are evoked with FEF stimulation and thus whether the FEF participates in gaze movement commands. We therefore examined the eye, head, and overall gaze movement evoked by low-intensity microstimulation of the low-threshold region of the FEF in two head-unrestrained monkeys. Microstimulation applied at 200 or 350 Hz for 200 ms evoked large gaze shifts with substantial head movement components from most sites in the dorsomedial FEF, but evoked small, predominantly eye-only gaze shifts from ventrolateral sites. The size and direction of gaze and eye movements were strongly affected by the eye position before stimulation. Head movements exhibited little position dependency, but at some sites and initial eye positions, head-only movements were evoked. Stimulus-evoked gaze shifts and their eye and head components resembled those elicited naturally by visual targets. With stimulus train durations >200 ms, the evoked gaze shifts were more likely to be accomplished with a substantial head movement, which often continued for the entire stimulus duration. The amplitude, duration and peak velocity of the evoked head movement were more strongly correlated with stimulus duration than were those of the gaze or eye movements. We conclude that the dorsomedial FEF generates a gaze command signal that can produce eye, head, or combined eye–head movement depending on the initial orbital position of the eye.

The effect of task set on fixational saccadic eye movements

2013 ◽  
Author(s):  
Sara Spotorno ◽  
Guillaume S. Masson ◽  
Anna Montagnini
Keyword(s):  
Eye Movements ◽  
Saccadic Eye Movements ◽  
Task Set
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