Smooth Pursuit Eye Movements in Normal and Dyslexic Children

1984 ◽  
Vol 59 (1) ◽  
pp. 91-100 ◽  
Author(s):  
J. L. Black ◽  
D. W. K. Collins ◽  
J. N. De Roach ◽  
S. R. Zubrick
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Significant Proportion ◽  
Saccadic Eye Movements ◽  
Poor Readers ◽  
Low Velocity ◽  
Poor Reading ◽  
Pursuit Eye Movements ◽  
Smooth Tracking ◽  
Normal Controls

This paper describes a detailed study of horizontal eye movements associated with visual tracking of a smoothly moving target. Essentially all children, even at target velocities as low as 5°/sec., show some saccadic eye movements superimposed on smooth tracking movements. Detailed analysis of pursuit eye-movements from a group of 26 poor readers and 34 normal controls (8 to 13 yr.) showed that about 25% of poor readers have an abnormally raised saccadic component in smooth pursuit. This suggests that studies of eye movements during tracking of smoothly moving targets at low velocity, combined with a quantitative approach to data analysis, may be useful for early detection of a significant proportion of poor-reading children.

Role of the Cerebellar Flocculus Region in the Coordination of Eye and Head Movements During Gaze Pursuit

2000 ◽  
Vol 84 (3) ◽  
pp. 1614-1626 ◽  
Author(s):  
Timothy Belton ◽  
Robert A. McCrea
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Head Movements ◽  
Whole Body ◽  
Head Tracking ◽  
Smooth Pursuit Eye Movements ◽  
Body Rotation ◽  
Pursuit Eye Movements ◽  
Smooth Tracking ◽  
Eye Velocity

The contribution of the flocculus region of the cerebellum to horizontal gaze pursuit was studied in squirrel monkeys. When the head was free to move, the monkeys pursued targets with a combination of smooth eye and head movements; with the majority of the gaze velocity produced by smooth tracking head movements. In the accompanying study we reported that the flocculus region was necessary for cancellation of the vestibuloocular reflex (VOR) evoked by passive whole body rotation. The question addressed in this study was whether the flocculus region of the cerebellum also plays a role in canceling the VOR produced by active head movements during gaze pursuit. The firing behavior of 121 Purkinje (Pk) cells that were sensitive to horizontal smooth pursuit eye movements was studied. The sample included 66 eye velocity Pk cells and 55 gaze velocity Pk cells. All of the cells remained sensitive to smooth pursuit eye movements during combined eye and head tracking. Eye velocity Pk cells were insensitive to smooth pursuit head movements. Gaze velocity Pk cells were nearly as sensitive to active smooth pursuit head movements as they were passive whole body rotation; but they were less than half as sensitive (≈43%) to smooth pursuit head movements as they were to smooth pursuit eye movements. Considered as a whole, the Pk cells in the flocculus region of the cerebellar cortex were <20% as sensitive to smooth pursuit head movements as they were to smooth pursuit eye movements, which suggests that this region does not produce signals sufficient to cancel the VOR during smooth head tracking. The comparative effect of injections of muscimol into the flocculus region on smooth pursuit eye and head movements was studied in two monkeys. Muscimol inactivation of the flocculus region profoundly affected smooth pursuit eye movements but had little effect on smooth pursuit head movements or on smooth tracking of visual targets when the head was free to move. We conclude that the signals produced by flocculus region Pk cells are neither necessary nor sufficient to cancel the VOR during gaze pursuit.

scholarly journals The saccadic system does not compensate for the immaturity of the smooth pursuit system during visual tracking in children

2013 ◽  
Vol 110 (2) ◽  
pp. 358-367 ◽  
Author(s):  
Caroline Ego ◽  
Jean-Jacques Orban de Xivry ◽  
Marie-Cécile Nassogne ◽  
Demet Yüksel ◽  
Philippe Lefèvre
Keyword(s):  
Eye Movements ◽  
Motor Skills ◽  
Smooth Pursuit ◽  
Saccadic Eye Movements ◽  
Lower Sensitivity ◽  
Early Maturity ◽  
Pursuit Eye Movements ◽  
Saccadic System ◽  
Pursuit System ◽  
Average Position

Motor skills improve with age from childhood into adulthood, and this improvement is reflected in the performance of smooth pursuit eye movements. In contrast, the saccadic system becomes mature earlier than the smooth pursuit system. Therefore, the present study investigates whether the early mature saccadic system compensates for the lower pursuit performance during childhood. To answer this question, horizontal eye movements were recorded in 58 children (ages 5–16 yr) and 16 adults (ages 23–36 yr) in a task that required the combination of smooth pursuit and saccadic eye movements. Smooth pursuit performance improved with age. However, children had larger average position error during target tracking compared with adults, but they did not execute more saccades to compensate for their low pursuit performance despite the early maturity of their saccadic system. This absence of error correction suggests that children have a lower sensitivity to visual errors compared with adults. This reduced sensitivity might stem from poor internal models and longer processing time in young children.

Single-neuron activity in the dorsomedial frontal cortex during smooth-pursuit eye movements to predictable target motion

1997 ◽  
Vol 14 (5) ◽  
pp. 853-865 ◽  
Author(s):  
S. J. Heinen ◽  
M. Liu
Keyword(s):  
Eye Movements ◽  
Frontal Cortex ◽  
Smooth Pursuit ◽  
Saccadic Eye Movements ◽  
Target Motion ◽  
Neuron Activity ◽  
Smooth Pursuit Eye Movements ◽  
Pursuit Eye Movements ◽  
Supplementary Eye Field ◽  
Dorsomedial Frontal Cortex

AbstractA region of dorsomedial frontal cortex (DMFC) has been implicated in planning and executing saccadic eye movements; hence it has been referred to as a supplementary eye field (SEF). Recently, activity related to executing smooth-pursuit eye movements has been recorded from the DMFC, and microstimulation here has been shown to evoke smooth eye movements. This report documents neuronal activity present in smooth-pursuit tasks where the predictability of target motion was manipulated. The activity of many neurons in the DMFC reached a peak when a predictable change in target motion occurred. Furthermore, the peak activity of some cells was systematically shifted by manipulating the duration of the target event, indicating that the network these neurons were in could learn the temporal characteristics of new target motion. Finally, the activity of most neurons tested was greater when target motion was predictable than when it was unpredictable. The results suggest that the DMFC participates in planning smooth-pursuit eye movements based on past stimulus history.

Extraretinal Inputs to Neurons in the Rostral Superior Colliculus of the Monkey During Smooth-Pursuit Eye Movements

2001 ◽  
Vol 86 (5) ◽  
pp. 2629-2633 ◽  
Author(s):  
Richard J. Krauzlis
Keyword(s):  
Eye Movements ◽  
Superior Colliculus ◽  
Smooth Pursuit ◽  
Saccadic Eye Movements ◽  
Visual Response ◽  
Smooth Pursuit Eye Movements ◽  
Related Activity ◽  
Pursuit Eye Movements ◽  
Deep Layers ◽  
Almost All

The intermediate and deep layers of the monkey superior colliculus (SC) are known to be important for the generation of saccadic eye movements. Recent studies have also provided evidence that the rostral SC might be involved in the control of pursuit eye movements. However, because rostral SC neurons respond to visual stimuli used to guide pursuit, it is also possible that the pursuit-related activity is simply a visual response. To test this possibility, we recorded the activity of neurons in the rostral SC as monkeys smoothly pursued a target that was briefly extinguished. We found that almost all rostral SC neurons in our sample maintained their pursuit-related activity during a brief visual blink, which was similar to the maintained activity they also exhibited during blinks imposed during fixation. These results indicate that discharge of rostral SC neurons during pursuit is not simply a visual response, but includes extraretinal signals.

Pursuit Subregion of the Frontal Eye Field Projects to the Caudate Nucleus in Monkeys

2003 ◽  
Vol 89 (5) ◽  
pp. 2678-2684 ◽  
Author(s):  
Dong-Mei Cui ◽  
Yi-Jun Yan ◽  
James C. Lynch
Keyword(s):  
Eye Movements ◽  
Basal Ganglia ◽  
Caudate Nucleus ◽  
Smooth Pursuit ◽  
Saccadic Eye Movements ◽  
Frontal Eye Field ◽  
Smooth Pursuit Eye Movements ◽  
Axon Terminals ◽  
Pursuit Eye Movements ◽  
Eye Field

It has been well established by recording, inactivation, and neuroanatomical studies that the caudate nucleus is important for the control of saccadic eye movements. However, until now, there has been little evidence that the caudate nucleus plays a role in smooth pursuit eye movements. In the present study, we physiologically identified the smooth pursuit subregion of the frontal eye field (FEFsem) and the saccadic subregion of the frontal eye field (FEFsac) in four Cebus monkeys. Anterogradely transported tracers (biotinylated dextran amines and wheat germ aglutinin conjugated to horseradish peroxidase) were then used to determine the efferent connections of the FEFsem to the caudate nucleus and to compare those connections with projections arising in the FEFsac. We observed dense projections from the FEFsem to the head and body of the caudate. The FEFsem and FEFsac terminal fields were of approximately equal density and total area. The region of FEFsem-labeled axon terminals overlapped only slightly with the region of FEFsac-labeled terminals. These results suggest that the caudate nucleus may play an important role in the control of smooth pursuit eye movements via feedback loops involving the basal ganglia and thalamus. Our results further suggest that the basal ganglia circuitry concerned with controlling visual pursuit is physically segregated from that concerned with controlling saccadic eye movements.

Functional neuroanatomy of smooth pursuit eye movements in normal controls and schizophrenic patients

1997 ◽  
Vol 24 (1-2) ◽  
pp. 172
Author(s):  
David E. Ross ◽  
Henry H. Holcomb ◽  
Gunvant K. Thaker ◽  
Robert Buchanan ◽  
Deborah R. Medoff ◽  
...  
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Smooth Pursuit Eye Movements ◽  
Functional Neuroanatomy ◽  
Pursuit Eye Movements ◽  
Schizophrenic Patients ◽  
Normal Controls
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