Eye movements during rapid pointing under risk (original) (raw)
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Human Movement Science, 2004
The present experiment examined the one-target advantage (OTA) with regard to saccadic eye movements. The OTA, previously found with manual pointing responses, refers to the finding that movements are executed faster when the limb is allowed to stop on the target compared to the situation where it has to proceed and hit a second target. Using an adapted limb movement OTA task, saccades of 5°and 15°were made to (a) a single target (one-target), (b) one target and immediately to another target without a change in direction (two-target-extension), and (c) one target and immediately back to the start location (two-target-reversal). Unlike manual movements, the movement times for the initial saccade in the two-target-extension condition were not prolonged compared to either of the other two conditions. Moreover, this pattern of results was found for both the shorter and longer amplitude saccades. The results indicate that the OTA does not occur in the oculomotor system and therefore is not a general motor control phenomenon.
Attentional selection during preparation of eye movements
Psychological research, 2004
Two experiments were conducted to examine the relationship between visual attention and saccade programming. Participants had to saccade to a letter string and detect a letter change presented briefly before the saccade onset. Hit probability (i.e., correct detection of a letter change in different positions) was taken as a measure of visual attention focus. The first experiment shows that hit probability depends on the actual landing position. These findings argue for a spatial coupling between saccade programming and the orienting of attention. Also, an unfamiliar letter cluster at the beginning captures attention and prevails over the influence of the saccade in preparation. Experiment 2, in which the letter change occurred at different times during the saccade latency, shows that attention shifts and focuses on the saccade target at the expense of the other parts of the stimulus when the motor program is ready to be executed. The theoretical implications of these results are discussed.
Contrasting effects of exogenous cueing on saccades and reaches
Journal of Vision, 2018
Previous studies have shown that eye and arm movements tend to be intrinsically coupled in their behavior. There is, however, no consensus on whether planning of eye and arm movements is based on shared or independent representations. One way to gain insight into these processes is to compare how exogenous attentional modulation influences the temporal and spatial characteristics of the eye and the arm during single or combined movements. Thirteen participants (M ¼ 22.8 years old, SD ¼ 1.5) performed single or combined movements to an eccentric target. A behaviorally irrelevant cue flashed just before the target at different locations. There was no effect of the cue on the saccade or reach amplitudes, whether they were performed alone or together. We found no differences in overall reaction times (RTs) between single and combined movements. With respect to the effect of the cue, both saccades and reaches followed a similar pattern with the shortest RTs when the cue was closest to the target, which we propose reflects effector-independent processes. Compared to when no cue was presented before the target, saccade RTs were generally inhibited by the irrelevant cue with increasing cue-target distance. In contrast, reach RTs showed strong facilitation at the target location and less facilitation at farther distances. We propose that this reflects the presence of effectordependent processes. The similarities and differences in RTs between the saccades and reaches are consistent with effector-dependent and-independent processes working in parallel.
Top-down influences make saccades deviate away: The case of endogenous cues
Acta Psychologica, 2007
We tested a recent hypothesis suggesting that the eye deviates away from a location when topdown preparation can inXuence target selection. Participants had to make an eye movement to a peripheral target. Before the upcoming target, a central cue indicated the likely target location. Results show that when the target was presented at a location diVerent from that indicated by the cue, eye movements to the target deviated away from the cued location. Because central cues are under top-down control, the present results are in line with a determining role of top-down preparation on saccade direction. These results contrast with the Wndings reported in a similar paradigm executed with hand movements, in which the movements were mostly initiated in the direction of the cued location. Therefore, we conclude that inhibitory eVects typically observed when executing eye movements may not be observed when executing hand movements in similar conditions.
Strategic control over saccadic eye movements: Studies of the fixation offset effect
Perception & Psychophysics, 2000
We studied the strategic (presumably cortical) control of ocular fixation in experiments that measured the fixation offset effect (FOE) while manipulating readiness to make reflexive or voluntary eye movements. The visual grasp reflex, which generates reflexive saccades to peripheral visual signals, reflects an opponent process in the superior colliculus (SC) between fixation cells at the rostral pole, whose activity helps maintain ocular position and increases when a stimulus is present at fixation, and movement cells, which generate saccades and are inhibited by rostral fixation neurons. Voluntary eye movements are controlled by movement and fixation cells in the frontal eye field (FEF). The FOE-a decrease in saccade latency when the fixation stimulus is extinguished-has been shown to reflect activity in the collicular eye movement circuitry and also to have an activity correlate in the FEF. Our manipulation of preparatory set to make reflexive or voluntary eye movements showed that when reflexive saccades were frequent and voluntary saccades were infrequent, the FOE was attenuated only for reflexive saccades. When voluntary saccades were frequent and reflexive saccades were infrequent, the FOE was attenuated only for voluntary saccades. Weconclude that cortical processes related to task strategy are able to decrease fixation neuron activity even in the presence of a fixation stimulus, resulting in a smaller FOE. The dissociation in the effects of a fixation stimulus on reflexive and voluntary saccade latencies under the same strategic set suggests that the FOEs for these two types of eye movements may reflect a change in cellular activity in different neural structures, perhaps in the SC for reflexive saccades and in the FEF for voluntary saccades.
Efficient Avoidance of the Penalty Zone in Human Eye Movements
PLOS ONE
People use eye movements extremely effectively to find objects of interest in a cluttered visual scene. Distracting, task-irrelevant attention capturing regions in the visual field should be avoided as they jeopardize the efficiency of search. In the current study, we used eye tracking to determine whether people are able to avoid making saccades to a predetermined visual area associated with a financial penalty, while making fast and accurate saccades towards stimuli placed near the penalty area. We found that in comparison to the same task without a penalty area, the introduction of a penalty area immediately affected eye movement behaviour: the proportion of saccades to the penalty area was immediately reduced. Also, saccadic latencies increased, but quite modestly, and mainly for saccades towards stimuli near the penalty area. We conclude that eye movement behaviour is under efficient cognitive control and thus quite flexible: it can immediately be adapted to changing environmental conditions to improve reward outcome.
Gaze is driven by an internal goal trajectory in a visuomotor task
European Journal of Neuroscience, 2013
When we make hand movements to visual targets, gaze usually leads hand position by a series of saccades to task-relevant locations. Recent research suggests that the slow smooth pursuit eye movement system may interact with the saccadic system in complex tasks, suggesting that the smooth pursuit system can receive non-retinal input. We hypothesise that a combination of saccades and smooth pursuit guides the hand movements towards a goal in a complex environment, using an internal representation of future trajectories as input to the visuomotor system. This would imply that smooth pursuit leads hand position, which is remarkable, as the general idea is that smooth pursuit is driven by retinal slip. To test this hypothesis, we designed a video-game task in which human subjects used their thumbs to move two cursors to a common goal position while avoiding stationary obstacles. We found that gaze led the cursors by a series of saccades interleaved with ocular fixation or pursuit. Smooth pursuit was correlated with neither cursor position nor cursor velocity. We conclude that a combination of fast and slow eye movements, driven by an internal goal instead of a retinal goal, led the cursor movements, and that both saccades and pursuit are driven by an internal representation of future trajectories of the hand. The lead distance of gaze relative to the hand may reflect a compromise between exploring future hand (cursor) paths and verifying that the cursors move along the desired paths.