Competition Between Saccade Goals in the Superior Colliculus Produces Saccade Curvature

McPeek, Robert M.; Han, Jae Hui; Keller, Edward L.

doi:10.1152/jn.00657.2002

Cited by 222 publications

(265 citation statements)

References 46 publications

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“…The second problem concerns the discrete nature of the target position sampling (Barmack, 1970;Fleuriet et al, 2011). A discrete sampling is indeed questioned by experiments showing that two saccades made to different goals can be concurrently programmed, even just before launching a saccade (McPeek and Keller, 2001;McPeek et al, 2003;Port and Wurtz, 2003). The last problem concerns the time interval during which target motion signals are integrated to encode the displacement of the target after its position is sampled.…”

Section: Discussionmentioning

confidence: 99%

Saccadic Interception of a Moving Visual Target after a Spatiotemporal Perturbation

Filippi¹,

Goffart²

2012

J. Neurosci.

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Animals can make saccadic eye movements to intercept a moving object at the right place and time. Such interceptive saccades indicate that, despite variable sensorimotor delays, the brain is able to estimate the current spatiotemporal (hic et nunc) coordinates of a target at saccade end. The present work further tests the robustness of this estimate in the monkey when a change in eye position and a delay are experimentally added before the onset of the saccade and in the absence of visual feedback. These perturbations are induced by brief microstimulation in the deep superior colliculus (dSC). When the microstimulation moves the eyes in the direction opposite to the target motion, a correction saccade brings gaze back on the target path or very near. When it moves the eye in the same direction, the performance is more variable and depends on the stimulated sites. Saccades fall ahead of the target with an error that increases when the stimulation is applied more caudally in the dSC. The numerous cases of compensation indicate that the brain is able to maintain an accurate and robust estimate of the location of the moving target. The inaccuracies observed when stimulating the dSC that encodes the visual field traversed by the target indicate that dSC microstimulation can interfere with signals encoding the target motion path. The results are discussed within the framework of the dual-drive and the remapping hypotheses.

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Section: Discussionmentioning

confidence: 99%

Saccadic Interception of a Moving Visual Target after a Spatiotemporal Perturbation

Filippi¹,

Goffart²

2012

J. Neurosci.

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“…Large shifts in SC activity during a saccade can thus redirect the saccade to another point. Such an assumption seems justified in the face of evidence that saccades can be redirected mid-flight (Amador et al 1998), and that saccades can be curved under the influence of for example distractors in the visual field (Ludwig and Gilchrist 2003;McPeek et al 2003;Port and Wurtz 2003;Van der Stigchel and Theeuwes 2005;Walker et al 1997). We do not claim that the SC determines the exact trajectory of a saccade, since there is enough evidence that it does not (Bergeron et al 2003;Goossens and Van Opstal 2000;Quaia et al 1998).…”

Section: Saccade Initiation and Trajectorymentioning

confidence: 99%

A competitive integration model of exogenous and endogenous eye movements

2010

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We present a model of the eye movement system in which the programming of an eye movement is the result of the competitive integration of information in the superior colliculi (SC). This brain area receives input from occipital cortex, the frontal eye fields, and the dorsolateral prefrontal cortex, on the basis of which it computes the location of the next saccadic target. Two critical assumptions in the model are that cortical inputs are not only excitatory, but can also inhibit saccades to specific locations, and that the SC continue to influence the trajectory of a saccade while it is being executed. With these assumptions, we account for many neurophysiological and behavioral findings from eye movement research. Interactions within the saccade map are shown to account for effects of distractors on saccadic reaction time (SRT) and saccade trajectory, including the global effect and oculomotor capture. In addition, the model accounts for express saccades, the gap effect, saccadic reaction times for antisaccades, and recorded responses from neurons in the SC and frontal eye fields in these tasks.

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“…Such a mode of packaged programming may be particularly facilitated if stimuli are all presented before the first gaze shift in a reasonably predictable manner so that the desired sequence of saccades is produced as a unit (Zingale and Kowler 1987). Alternatively, curved saccades with brief intersaccadic intervals, which have been observed in visual search as well as double-step tasks (e.g., Becker and Jurgens 1979;Findlay and Harris 1984;McPeek et al 2003;Minken et al 1993 However, other saccadic experiments have been conducted that raise the possibility of concurrent motor preparation (Vergilino and Beauvillain 2000). In the latter study, the authors examined the preprocessing of a refixation saccade to target words as the word length was either increased or reduced at different times after the primary saccade.…”

Section: Parallel Programming During Error Correctionmentioning

confidence: 99%

Control of Predictive Error Correction During a Saccadic Double-Step Task

Sharika¹,

Ramakrishnan²,

Murthy³

2008

Journal of Neurophysiology

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Sharika KM, Ramakrishnan A, Murthy A. Control of predictive error correction during a saccadic double-step task. J Neurophysiol 100: 2757-2770, 2008. First published September 24, 2008 doi:10.1152/jn.90238.2008. We explored the nature of control during error correction using a modified saccadic double-step task in which subjects cancelled the initial saccade to the first target and redirected gaze to a second target. Failure to inhibit was associated with a quick corrective saccade, suggesting that errors and corrections may be planned concurrently. However, because saccade programming constitutes a visual and a motor stage of preparation, the extent to which parallel processing occurs in anticipation of the error is not known. To estimate the time course of error correction, a triple-step condition was introduced that displaced the second target during the error. In these trials, corrective saccades directed at the location of the target prior to the third step suggest motor preparation of the corrective saccade in parallel with the error. To estimate the time course of motor preparation of the corrective saccade, further, we used an accumulator model (LATER) to fit the reaction times to the triple-step stimuli; the best-fit data revealed that the onset of correction could occur even before the start of the error. The estimated start of motor correction was also observed to be delayed as target step delay decreased, suggesting a form of interference between concurrent motor programs. Taken together we interpret these results to indicate that predictive error correction may occur concurrently while the oculomotor system is trying to inhibit an unwanted movement and suggest how inhibitory control and error correction may interact to enable goal-directed behaviors.

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Competition Between Saccade Goals in the Superior Colliculus Produces Saccade Curvature

Cited by 222 publications

References 46 publications

Saccadic Interception of a Moving Visual Target after a Spatiotemporal Perturbation

Saccadic Interception of a Moving Visual Target after a Spatiotemporal Perturbation

A competitive integration model of exogenous and endogenous eye movements

Control of Predictive Error Correction During a Saccadic Double-Step Task

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