Gaze-shift dynamics in two kinds of sequential looking tasks

Epelboim, Julie; Steinman, Robert M.; Kowler, Eileen; Pizlo, Zygmunt; Erkelens, Casper J.; Collewijn, H.

doi:10.1016/s0042-6989(97)00075-8

Cited by 96 publications

(90 citation statements)

References 12 publications

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“…Saccades to acoustic (Zambarbieri et al 1982) and tactile targets (Groh and Sparks 1996) are slower. The main sequence also depends on the subject's visual task such as just looking at visual targets or actually tapping the targets (Epelboim et al 1997) or pointing to real or remembered targets (Smit et al 1987). However, all these main sequences have a similar shape and the task may determine the relative weighting of movement and fixation cost.…”

Section: Discussionmentioning

confidence: 99%

The Main Sequence of Saccades Optimizes Speed-accuracy Trade-off

2006

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In primates, it is well known that there is a consistent relationship between the duration, peak velocity and amplitude of saccadic eye movements, known as the 'main sequence'. The reason why such a stereotyped relationship evolved is unknown. We propose that a fundamental constraint on the deployment of foveal vision lies in the motor system that is perturbed by signaldependent noise on the motor command. This noise imposes a compromise between the speed and accuracy of an eye movement. We propose that saccade trajectories have evolved to optimize a trade-off between the accuracy and duration of the movement. Taking a semi-analytical approach we use Pontryagin's minimum principle to show that there is an optimal trajectory for a given amplitude and duration; and that there is an optimal duration for a given amplitude. It follows that the peak velocity is also fixed for a given amplitude. These predictions are in good agreement with observed saccade trajectories and the main sequence. Moreover, this model predicts a small saccadic dead-zone in which it is better to stay eccentric of target than make a saccade onto target. We conclude that the main sequence has evolved as a strategy to optimize the trade-off between accuracy and speed.

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Section: Discussionmentioning

confidence: 99%

The Main Sequence of Saccades Optimizes Speed-accuracy Trade-off

2006

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“…Steinman et al (1990) showed that applying a bite-board reduces the peak velocity of eye movements to a much larger extent than could be explained by the contribution of the head movement. Epelboim et al (1997) showed that when subjects moved their hand to the target of a saccade, the peak velocity of the saccades was increased systematically. No mention of variability was made in these studies.…”

Section: Discussionmentioning

confidence: 99%

Nature of Variability in Saccades

Smeets¹,

Hooge²

2003

Journal of Neurophysiology

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We studied the variability in saccades by comparing the peak velocities of saccades with the same target amplitude made with different actual amplitudes. We tested three hypotheses: the pulse-height noise hypothesis (peak velocity and amplitude vary proportionally), the localization noise hypothesis (variability in amplitude and peak velocity lie along the main sequence), and the independent noise hypothesis (variability in amplitude and peak velocity are independent). We measured eye orientation in two experiments by a scleral coil and a video system. Surprisingly, the main source of variability of saccades depended on the measurement system used. A combination of localization noise and independent noise best describes the data obtained by the video system. The independent noise (e.g., measurement inaccuracy) was the main source of variability. For the scleral coils, the variability was considerably larger than for the less accurate video system. The pulse-height noise hypothesis best describes this additional variability. Therefore we conclude that pulse-height noise is the main source of variability in saccades measured with scleral coils. We discuss the influence of scleral coils on saccade generation and suggest that a change in motor strategy due to the discomfort of wearing the coils might be the cause of the increased variability.

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“…The coupling is bidirectional in that the oculomotor system is also influenced when pointing responses are made with the hand. (Epelboim et al 1997;Lunenburger et al 2000;Snyder 2002; van Donkelaar and Lee, 1994;van Donkelaar et al 1992van Donkelaar et al , 1997van Donkelaar et al , 2000van Donkelaar et al , 2004.…”

Section: Introductionmentioning

confidence: 99%

Effects of postural support on eye hand interactions across development

2007

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Reaching to grasp an object of interest requires a complex sensorimotor transformation-involving eye, head, hand and postural systems. We show here that discontinuities in development of movement in these systems are dependent not only on age but also vary according to task constraints. Providing external postural support allows us to examine the differential influences of the eye on the hand and the hand on the eye as the ability to isolate and coordinate each system changes with age. Children 4-6 years old had significant difficulty isolating eye movement from head or hand movement, whereas children 7-9 years old showed improved ability to isolate the eye, and by 10-15 years children became proficient in isolating hand movements from eye movements. Postural support had differential effects on the processes of initiation and execution of eye hand movements. The addition of postural support decreased the time needed for planning the movement, especially in the youngest children, and contributed to increased speed of isolated movements, whereas it caused differential slowing of coordinated movements depending on the child's developmental level. We suggest that the complexity of the results reflects the complexity of changing task requirements as children transition from simpler ballistic control of all systems to flexible, independent but coordinated control of multiple systems.

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Gaze-shift dynamics in two kinds of sequential looking tasks

Cited by 96 publications

References 12 publications

The Main Sequence of Saccades Optimizes Speed-accuracy Trade-off

The Main Sequence of Saccades Optimizes Speed-accuracy Trade-off

Nature of Variability in Saccades

Effects of postural support on eye hand interactions across development

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