Context-specific adaptation of saccade gain in parabolic flight

2003 ◽  
Vol 12 (5-6) ◽  
pp. 211-221 ◽  
Author(s):  
Mark Shelhamer ◽  
Richard A. Clendaniel ◽  
Dale C. Roberts

Previous studies established that vestibular reflexes can have two adapted states (e.g., gains) simultaneously, and that a context cue (e.g., vertical eye position) can switch between the two states. Our earlier work demonstrated this phenomenon of context-specific adaptation for saccadic eye movements: we asked for gain decrease in one context state and gain increase in another context state, and then determined if a change in the context state would invoke switching between the adapted states. Horizontal and vertical eye position and head orientation could serve, to varying degrees, as cues for switching between two different saccade gains. In the present study, we asked whether gravity magnitude could serve as a context cue: saccade adaptation was performed during parabolic flight, which provides alternating levels of gravitoinertial force (0 g and 1.8 g). Results were less robust than those from ground experiments, but established that different saccade magnitudes could be associated with different gravity levels.

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Afsheen Khan ◽  
Sally A. McFadden ◽  
Mark Harwood ◽  
Josh Wallman

When saccadic eye movements consistently fail to land on their intended target, saccade accuracy is maintained by gradually adapting the movement size of successive saccades. The proposed error signal for saccade adaptation has been based on the distance between where the eye lands and the visual target (retinal error). We studied whether the error signal could alternatively be based on the distance between the predicted and actual locus of attention after the saccade. Unlike conventional adaptation experiments that surreptitiously displace the target once a saccade is initiated towards it, we instead attempted to draw attention away from the target by briefly presenting salient distractor images on one side of the target after the saccade. To test whether less salient, more predictable distractors would induce less adaptation, we separately used fixed random noise distractors. We found that both visual attention distractors were able to induce a small degree of downward saccade adaptation but significantly more to the more salient distractors. As in conventional adaptation experiments, upward adaptation was less effective and salient distractors did not significantly increase amplitudes. We conclude that the locus of attention after the saccade can act as an error signal for saccade adaptation.


1994 ◽  
Vol 72 (6) ◽  
pp. 2754-2770 ◽  
Author(s):  
E. L. Keller ◽  
J. A. Edelman

1. We recorded the spatial and temporal dynamics of saccade-related burst neurons (SRBNs) found in the intermediate layers of the superior colliculus (SC) in the alert, behaving monkey. These burst cells are normally the first neurons recorded during radially directed microelectrode penetrations of the SC after the electrode has left the more dorsally situated visual layers. They have spatially delimited movement fields whose centers describe the well-studied motor map of the SC. They have a rather sharp, saccade-locked burst of activity that peaks just before saccade onset and then declines steeply during the saccade. Many of these cells, when recorded during saccade trials, also have an early, transient visual response and an irregular prelude of presaccadic activity. 2. Because saccadic eye movements normally have very stereotyped durations and velocity trajectories that vary systematically with saccade size, it has been difficult in the past to establish quantitatively whether the activity of SRBNs temporally codes dynamic saccadic control signals, e.g., dynamic motor error or eye velocity, where dynamic motor error is defined as a signal proportional to the instantaneous difference between desired final eye position and the actual eye position during a saccade. It has also not been unequivocally established whether SRBNs participate in an organized spatial shift of ensemble activity in the intermediate layers of the SC during saccadic eye movements. 3. To address these issues, we studied the activity of SRBNs using an interrupted saccade paradigm. Saccades were interrupted with pulsatile electrical stimulation through a microelectrode implanted in the omnipauser region of the brain stem while recordings were made simultaneously from single SRBNs in the SC. 4. Shortly after the beginning of the stimulation (which was electronically triggered at saccade onset), the eyes decelerated rapidly and stopped completely. When the high-frequency (typically 300-400 pulses per second) stimulation was terminated (average duration 12 ms), the eye movement was reinitiated and a resumed saccade was made accurately to the location of the target. 5. When we recorded from SRBNs in the more caudal colliculus, which were active for large saccades, cell discharge was powerfully and rapidly suppressed by the stimulation (average latency = 3.8 ms). Activity in the same cells started again just before the onset of the resumed saccade and continued during this saccade even though it has a much smaller amplitude than would normally be associated with significant discharge for caudal SC cells.(ABSTRACT TRUNCATED AT 400 WORDS)


1988 ◽  
Vol 1 (2) ◽  
pp. 239-244 ◽  
Author(s):  
James T. McIlwain

AbstractThe trajectories of saccadic eye movements evoked electrically from many brain structures are dependent to some degree on the initial position of the eye. Under certain conditions, likely to occur in stimulation experiments, local feedback models of the saccadic system can yield eye movements which behave in this way. The models in question assume that an early processing stage adds an internal representation of eye position to retinal error to yield a signal representing target position with respect to the head. The saccadic system is driven by the difference between this signal and one representing the current position of the eye. Albano & Wurtz (1982) pointed out that lesions perturbing the computation of eye position with respect to the head can result in initial position dependence of visually evoked saccades. It is shown here that position-dependent saccades will also result if electrical stimulation evokes a signal equivalent to retinal error but fails to effect a complete addition of eye position to this signal. Also, when multiple or staircase saccades are produced, as during long stimulus trains, they will have identical directions but decrease progressively in amplitude by a factor related to the fraction of added eye position.


1986 ◽  
Vol 56 (1) ◽  
pp. 196-207 ◽  
Author(s):  
A. McKenzie ◽  
S. G. Lisberger

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.


2021 ◽  
Author(s):  
Sebastian H. Zahler ◽  
David E. Taylor ◽  
Julia M. Adams ◽  
Evan H. Feinberg

AbstractHumans read text, recognize faces, and process emotions using targeted saccadic eye movements. In the textbook model, this innate ability to make targeted saccades evolved in species with foveae or similar high-acuity retinal specializations that enable scrutiny of salient stimuli. According to the model, saccades made by species without retinal specializations (such as mice) are never targeted and serve only to reset the eyes after gaze-stabilizing movements. Here we show that mice innately make touch-evoked targeted saccades. Optogenetic manipulations revealed the neural circuit mechanisms underlying targeted saccades are conserved. Saccade probability is a U-shaped function of current eye position relative to the target, mirroring the simulated relationship between an object’s location within the visual field and the probability its next movement carries it out of view. Thus, a cardinal sophistication of our visual system may have had an unexpectedly early origin as an innate behavior that keeps stimuli in view.


1997 ◽  
Vol 37 (14) ◽  
pp. 1929-1937 ◽  
Author(s):  
Clifton M. Schor ◽  
Jeffrey W. McCandless

1991 ◽  
Vol 65 (5) ◽  
pp. 1170-1182 ◽  
Author(s):  
G. D. Paige ◽  
D. L. Tomko

1. The purpose of this study was to quantify the response characteristics of eye movements produced by linear head oscillations in the dark (the linear vestibuloocular reflex, or LVOR). Horizontal, vertical, and torsional eye movements were measured in adult squirrel monkeys by the use of a dual scleral search-coil technique during linear oscillations (0.5, 1.5, and 5.0 Hz, 0.36 g peak acceleration) along the animals' interaural (IA), dorsoventral (DV), and nasooccipital (NO) axes. 2. Two LVOR responses, horizontal eye movements during IA-axis translation and vertical eye movements during DV-axis motion, were in a compensatory direction for head translation. Response amplitudes increased as frequency increased, whereas phase typically showed a lead. 3. Two other LVORs, torsional responses during IA-axis translation (all frequencies) and vertical responses during NO-axis oscillations (0.5 Hz), behaved differently. These two LVORs cannot be functionally compensatory for head translation because they degrade fixation on targets, and therefore image stability, by rotating the eyes off target (NO-vertical) or torting the eyes relative to the visual world (IA-torsional). Responses to NO-axis motion at frequencies greater than 0.5 Hz depended on initial eye position and fixation distance and are described in the companion paper. 4. The effect of head orientation on the LVOR was assessed by testing four head positions in 90 degrees steps around the axis of head motion for each of the three axes of translation. This was done, first, to determine whether the LVORs are responses to the "swinging vector" of gravitoinertial force during linear head motion or to head translation; and second, to quantify potential effects of static head (otolith) orientation on the LVORs. Results showed no systematic effects of head orientation on LVOR responses in the frequency bandwidth studied. This indicates that the LVORs are dependent on the direction of linear motion relative to the head (and otolith organs) but not on the swinging vector of gravitoinertial force, and that the LVORs are uninfluenced by static orientation of the head and reloading of the otoliths.


1993 ◽  
Vol 69 (3) ◽  
pp. 800-818 ◽  
Author(s):  
G. S. Russo ◽  
C. J. Bruce

1. We quantitatively compared the effects of eye position within the orbit on saccadic eye movements electrically elicited from two oculomotor areas of the macaque monkey's frontal lobe cortex: the frontal eye field (FEF) and the supplementary eye field (SEF). 2. The effect of eye position on electrically elicited saccades was studied by delivering 70-ms trains of intracortical microstimulation while the monkeys fixated a spot of light. Tests of different fixation points located across a rectangular array were randomly intermixed. Complete experiments were carried out on 38 sites in three FEFs of two monkeys and 59 sites from three SEFs of the same two monkeys. Stimulation currents for the array experiments were usually 10–20 microA above the site threshold; the average current used was 36 microA for FEF and 49 microA for SEF. 3. The magnitude of effect of the initial eye position on the elicited saccade's dimensions was quantified at each site by computing the linear regression of saccadic eye movement displacement on the eye position within the orbit when stimulation was applied. This computation was done separately for the horizontal and vertical axes. We call the resulting pair of regression coefficients “orbital perturbation indexes.” Indexes of 0.0 represent elicited saccades that do not change their trajectory with different initial eye positions (constant-vector saccades), whereas indexes of -1.0 represent elicited saccades that end at the same orbital position regardless of initial eye position (goal-directed saccades). 4. The effect of eye position varied across sites. In both FEF and SEF, the orbital perturbation indexes were distributed between approximately 0.0 and -0.5, with the horizontal and vertical indexes highly correlated across sites. 5. The average orbital perturbation indexes were small for both eye fields and were not significantly different. The mean horizontal indexes were -0.13 and -0.16 for SEF and FEF, respectively. The mean vertical indexes were -0.16 and -0.13. Neither SEF versus FEF difference was statistically significant. 6. In both SEF and FEF, sites yielding larger-amplitude saccades generally had larger orbital effects than sites yielding smaller saccades. This relationship accounted for the majority of the variability of the orbital perturbation indexes across sites in both SEF and FEF. 7. These results indicate that SEF and FEF are not distinguished from each other by the orbital dependence of their electrically elicited saccades. Thus they do not confirm the previously hypothesized dichotomy that FEF codes constant-vector saccades and SEF codes goal-directed saccades.(ABSTRACT TRUNCATED AT 400 WORDS)


2000 ◽  
Vol 83 (4) ◽  
pp. 2374-2391 ◽  
Author(s):  
Alexandra Battaglia-Mayer ◽  
Stefano Ferraina ◽  
Takashi Mitsuda ◽  
Barbara Marconi ◽  
Aldo Genovesio ◽  
...  

Neural activity was recorded in the parietooccipital cortex while monkeys performed different tasks aimed at investigating visuomotor interactions of retinal, eye, and arm-related signals on neural activity. The tasks were arm reaching 1) to foveated targets; 2) to extrafoveal targets, with constant eye position; 3) within an instructed-delayed paradigm, under both light and darkness; 4) saccadic eye movements toward, and static eye holding on peripheral targets; and 5) visual fixation and stimulation. The activity of many cells was modulated during arm reaction (68%) and movement time (58%), and during static holding of the arm in space (64%), when eye position was kept constant. Eye position influenced the activity of many cells during hand reaction (45%) and movement time (51%) and holding of hand static position (69%). Many cells (56%) were also modulated during preparation for hand movement, in the delayed reach task. Modulation was present also in the dark in 59% of cells during this epoch, 51% during reaction and movement time, and 48% during eye/hand holding on the target. Cells (50%) displaying light-dark differences of activity were considered as related to the sight and monitoring of hand motion and/or position in the visual field. Saccadic eye movements modulated a smaller percentage (25%) of cells than eye position (68%). Visual receptive fields were mapped in 44% of the cells studied. They were generally large and extended to the periphery of the tested (30°) visual field. Sixty-six percent of cells were motion sensitive. Therefore the activity of many neurons in this area reflects the combined influence of visual, eye, and arm movement–related signals. For most neurons, the orientation of the preferred directions computed across different epochs and tasks, therefore expression of all different eye- and hand-related activity types, clustered within a limited sector of space, the field of global tuning. These spatial fields might be an ideal frame to combine eye and hand signals, thanks to the congruence of their tuning properties. The relationships between cell activity and oculomotor and visuomanual behavior were task dependent. During saccades, most cells were recruited when the eye moved to a spatial location that was also target for hand movement, whereas during hand movement most cells fired depending on whether or not the animal had prior knowledge about the location of the visual targets.


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