Velocity scaling of cue-induced smooth pursuit acceleration obeys constraints of natural motion

Ladda, J.; Eggert, Thomas; Glasauer, Stefan; Straube, Andreas

doi:10.1007/s00221-007-0988-y

Cited by 36 publications

(33 citation statements)

References 37 publications

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“…The control group, in contrast, showed a velocity dependence eliciting a higher slow-phase velocity at the higher target velocity. This was also described previously [10,15]. Several other studies on PD patients have also observed a reduced peak velocity as seen in our parkinsonian patients [16][17][18].…”

Section: Discussionsupporting

confidence: 80%

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Parkinsonian patients show impaired predictive smooth pursuit

Ladda¹,

Valkovič

Eggert³

et al. 2008

J Neurol

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To determine if patients with Parkinson's disease (PD) are able to use a visual contextual cue to induce a predictive change in smooth pursuit direction and if this ability depends on the state of the dopaminergic system, we measured predictive smooth pursuit in nine patients with mild to moderate PD during OFF and ON medication. These values were compared with those of nine age-matched and sex-matched healthy controls.Our focus was on the horizontal smooth pursuit when subjects pursued a downward moving target entering a+/-90 deg curve. The target moved on a homogeneous background or on a static "street" that indicated the future trajectory of the target. Our main result is that PD patients were impaired in eliciting predictive smooth pursuit using the context information of the street compared to healthy subjects. The control group elicited predictive pursuit 250 ms before target onset. In contrast, PD patients showed significantly longer latency (100-120 ms) and reduced maximal pursuit velocity. However, without the street guiding pursuit, a delay of about 250 ms was seen in both groups. There was no significant difference in the smooth pursuit performance between OFF and ON medication in the patient group.These results show that early stage PD patients are impaired in the use of static visual information as a cue for predictive pursuit compared to controls and that this deficit does not depend on dopaminergic medication. In the context of predictive eye movement, the involvement of the striatal-frontal pathway and the spatial working memory is discussed.

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Section: Discussionsupporting

confidence: 80%

“…The exact method of how the slow-phase velocity (SPV) of the horizontal smooth pursuit was computed has been described previously in detail [10]. Trials with more than one saccade during the curve were excluded from analysis.…”

Section: ■ Data Analysismentioning

confidence: 99%

Parkinsonian patients show impaired predictive smooth pursuit

Ladda¹,

Valkovič

Eggert³

et al. 2008

J Neurol

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“…Saccades were detected and removed with a slow-phase estimation algorithm as described previously (Ladda et al 2007). Briefly, an estimate of the slow-phase component (SPC) was initialized to zero and iteratively improved in each step.…”

Section: Discussionmentioning

confidence: 99%

The Response of MSTd Neurons to Perturbations in Target Motion During Ongoing Smooth-Pursuit Eye Movements

Ono

Brostek

Nuding

et al. 2010

Journal of Neurophysiology

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Ono S, Brostek L, Nuding U, Glasauer S, Bü ttner U, Mustari MJ. The response of MSTd neurons to perturbations in target motion during ongoing smooth-pursuit eye movements. J Neurophysiol 103: 519 -530, 2010. First published November 18, 2009 doi:10.1152/jn.00563.2009. Several regions of the brain are involved in smooth-pursuit eye movement (SPEM) control, including the cortical areas MST (medial superior temporal) and FEF (frontal eye field). It has been shown that the eye-movement responses to a brief perturbation of the visual target during ongoing pursuit increases with higher pursuit velocities. To further investigate the underlying neuronal mechanism of this nonlinear dynamic gain control and the contributions of different cortical areas to it, we recorded from MSTd (dorsal division of the MST area) neurons in behaving monkeys (Macaca mulatta) during step-ramp SPEM (5-20°/s) with and without superimposed target perturbation (one cycle, 5 Hz, Ϯ10°/s). Smoothpursuit-related MSTd neurons started to increase their activity on average 127 ms after eye-movement onset. Target perturbation consistently led to larger eye-movement responses and decreasing latencies with increasing ramp velocities, as predicted by dynamic gain control. For 36% of the smooth-pursuit-related MSTd neurons the eye-movement perturbation was accompanied by detectable changes in neuronal activity with a latency of 102 ms, with respect to the eye-movement response. The remaining smooth-pursuit-related MSTd neurons (64%) did not reflect the eye-movement perturbation. For the large majority of cases this finding could be predicted by the dynamic properties of the step-ramp responses. Almost all these MSTd neurons had large visual receptive fields responding to motion in preferred directions opposite to the optimal SPEM stimulus. Based on these findings it is unlikely that MSTd plays a major role for dynamic gain control and initiation of the perturbation response. However, neurons in MSTd could still participate in SPEM maintenance. Due to their visual field properties they could also play a role in other functions such as self-motion perception.

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“…Eye movements were submitted to an iterative algorithm using velocity and acceleration criteria [14] to identify fast phases (saccades) and slow phases (fixations, vestibulo-ocular reflex movements). Fast phase entry and exit points were defined to occur at 10% of the maximal velocity of the corresponding saccade.…”

Section: Methodsmentioning

confidence: 99%

Visual Exploration during Locomotion Limited by Fear of Heights

et al. 2014

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BackgroundVisual exploration of the surroundings during locomotion at heights has not yet been investigated in subjects suffering from fear of heights.MethodsEye and head movements were recorded separately in 16 subjects susceptible to fear of heights and in 16 non-susceptible controls while walking on an emergency escape balcony 20 meters above ground level. Participants wore mobile infrared eye-tracking goggles with a head-fixed scene camera and integrated 6-degrees-of-freedom inertial sensors for recording head movements. Video recordings of the subjects were simultaneously made to correlate gaze and gait behavior.ResultsSusceptibles exhibited a limited visual exploration of the surroundings, particularly the depth. Head movements were significantly reduced in all three planes (yaw, pitch, and roll) with less vertical head oscillations, whereas total eye movements (saccade amplitudes, frequencies, fixation durations) did not differ from those of controls. However, there was an anisotropy, with a preference for the vertical as opposed to the horizontal direction of saccades. Comparison of eye and head movement histograms and the resulting gaze-in-space revealed a smaller total area of visual exploration, which was mainly directed straight ahead and covered vertically an area from the horizon to the ground in front of the feet. This gaze behavior was associated with a slow, cautious gait.ConclusionsThe visual exploration of the surroundings by susceptibles to fear of heights differs during locomotion at heights from the earlier investigated behavior of standing still and looking from a balcony. During locomotion, anisotropy of gaze-in-space shows a preference for the vertical as opposed to the horizontal direction during stance. Avoiding looking into the abyss may reduce anxiety in both conditions; exploration of the “vertical strip” in the heading direction is beneficial for visual control of balance and avoidance of obstacles during locomotion.

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Velocity scaling of cue-induced smooth pursuit acceleration obeys constraints of natural motion

Cited by 36 publications

References 37 publications

Parkinsonian patients show impaired predictive smooth pursuit

Parkinsonian patients show impaired predictive smooth pursuit

The Response of MSTd Neurons to Perturbations in Target Motion During Ongoing Smooth-Pursuit Eye Movements

Visual Exploration during Locomotion Limited by Fear of Heights

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