Effects of Asymmetric Vergence on Compensatory Eye Movements During Active Head Rotation1

1991 ◽  
Vol 1 (4) ◽  
pp. 357-371
Author(s):  
Trevor Hine

The kinematics of the horizontal VOR for near fixation demand that VOR gain should change dependent on the target distance and the orientation of the head with respect to the target, or, equivalently, the amount of ocular vergence and the asymmetry of this vergence. Across two experiments, the gain of the VOR was measured in the right eye of humans who rotated their heads to the right or left while viewing a target placed either 22, 32.5 or 200 cm from the center of head rotation, in conditions with and without visual feedback. When tbe eye was in-line with the target, the measured VOR gain was up to 43% greater than when the eye was in an eccentric position. However, in the eccentric position, higher VOR gains were achieved with visual feedback of the target than without feedback, indicative of a visual component in the compensatory eye movement. Also, by changing the posture of the left eye but keeping the right eye constant, the VOR gain in the right eye was changed substantially during a subsequent head rotation. Hence, the positions of both eyes in their orbits determine the gain of the VOR in each eye.

1993 ◽  
Vol 46 (1) ◽  
pp. 51-82 ◽  
Author(s):  
Harold Pashler ◽  
Mark Carrier ◽  
James Hoffman

Four dual-task experiments required a speeded manual choice response to a tone in a close temporal proximity to a saccadic eye movement task. In Experiment 1, subjects made a saccade towards a single transient; in Experiment 2, a red and a green colour patch were presented to left and right, and the saccade was to which ever patch was the pre-specified target colour. There was some slowing of the eye movement, but neither task combination showed typical dual-task interference (the “psychological refractory effect”). However, more interference was observed when the direction of the saccade depended on whether a central colour patch was red or green, or when the saccade was directed towards the numerically higher of two large digits presented to the left and the right. Experiment 5 examined a vocal second task, for comparison. The findings might reflect the fact that eye movements can be directed by two separate brain systems–-the superior colliculus and the frontal eye fields; commands from the latter but not the former may be delayed by simultaneous unrelated sensorimotor tasks.


Perception ◽  
1979 ◽  
Vol 8 (1) ◽  
pp. 21-30 ◽  
Author(s):  
Keith Rayner

Three broad categories of models of eye movement guidance in reading are described. According to one category, eye movements in reading are not under stimulus or cognitive control; the other two categories indicate that cognitive activities or stimulus characteristics are involved in eye guidance. In this study a number of descriptive analyses of eye movements in reading were carried out. These analyses dealt with fixation locations on letters within words of various lengths, conditional probabilities that a word will be fixated given that a prior word was or was not fixated, and average saccade length as a function of the length of the word to the right of the fixated word. The results of these analyses were supportive of models which suggest that determining where to look next while reading is made on a nonrandom basis.


1999 ◽  
Vol 81 (5) ◽  
pp. 2340-2346 ◽  
Author(s):  
Carl R. Olson ◽  
Sonya N. Gettner

Macaque SEF neurons encode object-centered directions of eye movements regardless of the visual attributes of instructional cues. Neurons in the supplementary eye field (SEF) of the macaque monkey exhibit object-centered direction selectivity in the context of a task in which a spot flashed on the right or left end of a sample bar instructs a monkey to make an eye movement to the right or left end of a target bar. To determine whether SEF neurons are selective for the location of the cue, as defined relative to the sample bar, or, alternatively, for the location of the target, as defined relative to the target bar, we carried out recording while monkeys performed a new task. In this task, the color of a cue-spot instructed the monkey to which end of the target bar an eye movement should be made (blue for the left end and yellow for the right end). Object-centered direction selectivity persisted under this condition, indicating that neurons are selective for the location of the target relative to the target bar. However, object-centered signals developed at a longer latency (by ∼200 ms) when the instruction was conveyed by color than when it was conveyed by the location of a spot on a sample bar.


2020 ◽  
Vol 123 (1) ◽  
pp. 243-258 ◽  
Author(s):  
Kristin N. Hageman ◽  
Margaret R. Chow ◽  
Dale Roberts ◽  
Charles C. Della Santina

Head rotation, translation, and tilt with respect to a gravitational field elicit reflexive eye movements that partially stabilize images of Earth-fixed objects on the retinas of humans and other vertebrates. Compared with the angular vestibulo-ocular reflex, responses to translation and tilt, collectively called the otolith-ocular reflex (OOR), are less completely characterized, typically smaller, generally disconjugate (different for the 2 eyes) and more complicated in their relationship to the natural stimuli that elicit them. We measured binocular 3-dimensional OOR responses of 6 alert normal chinchillas in darkness during whole body tilts around 16 Earth-horizontal axes and translations along 21 axes in horizontal, coronal, and sagittal planes. Ocular countertilt responses to 40-s whole body tilts about Earth-horizontal axes grew linearly with head tilt amplitude, but responses were disconjugate, with each eye’s response greatest for whole body tilts about axes near the other eye’s resting line of sight. OOR response magnitude during 1-Hz sinusoidal whole body translations along Earth-horizontal axes also grew with stimulus amplitude. Translational OOR responses were similarly disconjugate, with each eye’s response greatest for whole body translations along its resting line of sight. Responses to Earth-horizontal translation were similar to those that would be expected for tilts that would cause a similar peak deviation of the gravitoinertial acceleration (GIA) vector with respect to the head, consistent with the “perceived tilt” model of the OOR. However, that model poorly fit responses to translations along non-Earth-horizontal axes and was insufficient to explain why responses are larger for the eye toward which the GIA vector deviates. NEW & NOTEWORTHY As the first in a pair of papers on Binocular 3D Otolith-Ocular Reflexes, this paper characterizes binocular 3D eye movements in normal chinchillas during tilts and translations. The eye movement responses were used to create a data set to fully define the normal otolith-ocular reflexes in chinchillas. This data set provides the foundation to use otolith-ocular reflexes to back-project direction and magnitude of eye movement to predict tilt axis as discussed in the companion paper.


1996 ◽  
Vol 49 (4) ◽  
pp. 940-949 ◽  
Author(s):  
Mary M. Smyth

We have previously argued that rehearsal in spatial working memory is interfered with by spatial attention shifts rather than simply by movements to locations in space (Smyth & Scholey, 1994). It is possible, however, that the stimuli intended to induce attention shifts in our experiments also induced eye movements and interfered either with an overt eye movement rehearsal strategy or with a covert one. In the first experiment reported here, subjects fixated while they maintained a sequence of spatial items in memory before recalling them in order. Fixation did not affect recall, but auditory spatial stimuli presented during the interval did decrease performance, and it was further decreased if the stimuli were categorized as coming from the right or the left. A second experiment investigated the effects of auditory spatial stimuli to which no response was ever required and found that these did not interfere with performance, indicating that it is the spatial salience of targets that leads to interference. This interference from spatial input in the absence of any overt movement of the eyes or limbs is interpreted in terms of shifts of spatial attention or spatial monitoring, which Morris (1989) has suggested affects spatial encoding and which our findings suggest also affects reactivation in rehearsal.


1990 ◽  
Vol 64 (2) ◽  
pp. 489-508 ◽  
Author(s):  
M. E. Goldberg ◽  
C. J. Bruce

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)


1988 ◽  
Vol 67 (3) ◽  
pp. 943-954 ◽  
Author(s):  
Carolyn E. Kerr ◽  
Warren S. Brown

The relationship between personality and preference for use of the right or left hemisphere of the brain in cognitive processing was investigated. Lateral eye movements were recorded as 50 female and 20 male right-handed subjects considered questions requiring reflection. The questions were not obviously “verbal” or “spatial” in nature but did require differing levels of reflection. Questions requiring higher levels of reflection produced a higher rate of lateral eye movement responses. Percent right eye movement for individual subjects was then correlated with scores on the Sixteen Personality Factor Questionnaire, using both first-order factors and the second-order factor Cortertia, which has some face validity as describing the personality generally ascribed to those who produce mostly right lateral eye movements. No correlation was found between the preferred directions of eye movements and 16 PF factors, which suggests that the lateral eye movements reflect thinking and problem-solving strategies but are not associated with personality styles.


1977 ◽  
Vol 44 (3) ◽  
pp. 683-689 ◽  
Author(s):  
Amos S. Cohen ◽  
Herbert Studach

The eye fixations of 5 experienced and 4 inexperienced car drivers were analyzed while driving curves to the left and to the right. For experienced drivers in a curve to the left the mean duration of eye fixations was longer and the amplitude of the eye movements greater than in a curve to the right. No such difference was observed in inexperienced drivers who manifested neither uniformity within the same curves nor differentiation between the two types of curves. Mean duration of eye fixations of experienced subjects was shorter while driving in a curve to right, but their amplitude of eye movement was greater in a curve to left than those of inexperienced drivers. In Exp. 2, it was pointed out that there is already a change in the pattern of eye movements prior to entering a curve. Upon approaching the curve the mean duration of eye fixation decreased, and the fixations were mainly shifted toward the future driving path. Results are interpreted in terms of the adequacy of the eye fixations (supposedly influenced by prior long-term learning) for information at near distance for vehicle control and at longer distances for setting up proprioceptive forward programs for possible future sensomotoric activity.


Author(s):  
Martin H. Fischer ◽  
Nele Warlop ◽  
Robin L. Hill ◽  
Wim Fias

Abstract. Previous research with manual response methods has found evidence for an association between numbers and space. The present study investigated whether eye movements also show this association. Eye movement responses were recorded from 15 healthy participants as they categorized the digits 0-9 as odd or even. Responses were initiated faster to the left in response to small digits and faster to the right in response to large digits. Movement amplitudes were not systematically affected by either number magnitude or parity. These results provide further evidence for a spatially oriented “mental number line”.


1994 ◽  
Vol 72 (2) ◽  
pp. 909-927 ◽  
Author(s):  
S. G. Lisberger ◽  
T. A. Pavelko ◽  
D. M. Broussard

1. We have identified a group of brain stem cells called “flocculus target neurons” (or FTNs) because they are inhibited at monosynaptic latencies by stimulation of the flocculus and the ventral paraflocculus with single electrical pulses. We report the responses of FTNs, as well as those of other brain stem cells, during horizontal eye movements with the head stationary and during natural vestibular stimulation in monkeys. 2. FTNs discharged primarily in relation to eye movements. The majority (71%) showed increased firing for eye movement away from the side of the recording (“contraversive”), which is consistent with their inhibition by Purkinje cells that show increased firing for eye movement toward the side of recording. However, a significant and surprisingly large percentage (29%) of FTNs showed increased firing for eye movement toward the side of recording (“ipsiversive”). 3. The firing rate of FTNs showed strong modulation during pursuit of sinusoidal target motion with the head stationary and during the compensatory eye movements evoked by fixation of an earth-stationary target with sinusoidal head rotation. In addition, firing rate was related to eye position during steady fixation at different positions. Of the FTNs that showed increased firing for contraversive eye motion during pursuit with the head stationary, most had an infection in the relationship between firing rate and eye position so that the sensitivity to eye position was low for eye positions ipsilateral to straight-ahead gaze and high for eye positions contralateral to straight-ahead gaze. 4. When the monkey canceled the vestibuloocular reflex (VOR) by tracking a target that moved exactly with him during sinusoidal head rotation, the firing rate of FTNs was modulated much less strongly than during pursuit with the head stationary. In the FTNs that showed increased firing for contraversive eye motion during pursuit, firing rate during cancellation of the VOR increased for contraversive head motion during sinusoidal vestibular rotation at 0.4 Hz but was only weakly modulated during rotation at 0.2 Hz. 5. The position-vestibular-pause cells (PVP-cells), previously identified as interneurons in the disynaptic VOR pathways, were not inhibited by stimulation of the flocculus and ventral paraflocculus and had response properties that were different from FTNs. The majority (69%) showed increased firing for contraversive eye motion during pursuit and for ipsiversive head motion during cancellation of the VOR, whereas some (31%) showed the opposite direction preferences under both conditions.(ABSTRACT TRUNCATED AT 250 WORDS)


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