scholarly journals Partial Ablations of the Flocculus and Ventral Paraflocculus in Monkeys Cause Linked Deficits in Smooth Pursuit Eye Movements and Adaptive Modification of the VOR

2002 ◽  
Vol 87 (2) ◽  
pp. 912-924 ◽  
Author(s):  
H. Rambold ◽  
A. Churchland ◽  
Y. Selig ◽  
L. Jasmin ◽  
S. G. Lisberger
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Large Fraction ◽  
Head Rotation ◽  
Head Movements ◽  
Image Motion ◽  
Smooth Pursuit Eye Movements ◽  
Pursuit Eye Movements ◽  
Vor Adaptation ◽  
Ventral Paraflocculus

The vestibuloocular reflex (VOR) generates compensatory eye movements to stabilize visual images on the retina during head movements. The amplitude of the reflex is calibrated continuously throughout life and undergoes adaptation, also called motor learning, when head movements are persistently associated with image motion. Although the floccular-complex of the cerebellum is necessary for VOR adaptation, it is not known whether this function is localized in its anterior or posterior portions, which comprise the ventral paraflocculus and flocculus, respectively. The present paper reports the effects of partial lesions of the floccular-complex in five macaque monkeys, made either surgically or with stereotaxic injection of 3-nitropropionic acid (3-NP). Before and after the lesions, smooth pursuit eye movements were tested during sinusoidal and step-ramp target motion. Cancellation of the VOR was tested by moving a target exactly with the monkey during sinusoidal head rotation. The control VOR was tested during sinusoidal head rotation in the dark and during 30°/s pulses of head velocity. VOR adaptation was studied by having the monkeys wear ×2 or ×0.25 optics for 4–7 days. In two monkeys, bilateral lesions removed all of the flocculus except for parts of folia 1 and 2 but did not produce any deficits in smooth pursuit, VOR adaptation, or VOR cancellation. We conclude that the flocculus alone probably is not necessary for either pursuit or VOR learning. In two monkeys, unilateral lesions including a large fraction of the ventral paraflocculus produced small deficits in horizontal and vertical smooth pursuit, and mild impairments of VOR adaptation and VOR cancellation. We conclude that the ventral paraflocculus contributes to both behaviors. In one monkey, a bilateral lesion of the flocculus and ventral paraflocculus produced severe deficits smooth pursuit and VOR cancellation, and a complete loss of VOR adaptation. Considering all five cases together, there was a strong correlation between the size of the deficits in VOR learning and pursuit. We found the strongest correlation between the behavior deficits and the size of the lesion of the ventral paraflocculus, a weaker but significant correlation for the full floccular complex, and no correlation with the size of the lesion of the flocculus. We conclude that 1) lesions of the floccular complex cause linked deficits in smooth pursuit and VOR adaptation, and 2) the relevant portions of the structure are primarily in the ventral paraflocculus, although the flocculus may participate.

scholarly journals Illusory bending of a rigidly moving line segment: Effects of image motion and smooth pursuit eye movements

10.1167/7.6.9 ◽  
2007 ◽  
Vol 7 (6) ◽  
pp. 9 ◽  
Author(s):  
Lore Thaler ◽  
James T. Todd ◽  
Miriam Spering ◽  
Karl R. Gegenfurtner
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Line Segment ◽  
Image Motion ◽  
Smooth Pursuit Eye Movements ◽  
Pursuit Eye Movements ◽  
Moving Line

Contribution of the Cerebellar Flocculus to Gaze Control during Active Head Movements

1999 ◽  
Vol 81 (6) ◽  
pp. 3105-3109 ◽  
Author(s):  
T. Belton ◽  
R. A. McCrea
Keyword(s):  
Eye Movements ◽  
Cerebellar Cortex ◽  
Smooth Pursuit ◽  
Head Movements ◽  
Gaze Control ◽  
Smooth Pursuit Eye Movements ◽  
Ocular Pursuit ◽  
Pursuit Eye Movements ◽  
Cerebellar Flocculus ◽  
Visual Targets

Contribution of the cerebellar flocculus to gaze control during active head movements. The flocculus and ventral paraflocculus are adjacent regions of the cerebellar cortex that are essential for controlling smooth pursuit eye movements and for altering the performance of the vestibulo-ocular reflex (VOR). The question addressed in this study is whether these regions of the cerebellum are more globally involved in controlling gaze, regardless of whether eye or active head movements are used to pursue moving visual targets. Single-unit recordings were obtained from Purkinje (Pk) cells in the floccular region of squirrel monkeys that were trained to fixate and pursue small visual targets. Cell firing rate was recorded during smooth pursuit eye movements, cancellation of the VOR, combined eye-head pursuit, and spontaneous gaze shifts in the absence of targets. Pk cells were found to be much less sensitive to gaze velocity during combined eye–head pursuit than during ocular pursuit. They were not sensitive to gaze or head velocity during gaze saccades. Temporary inactivation of the floccular region by muscimol injection compromised ocular pursuit but had little effect on the ability of monkeys to pursue visual targets with head movements or to cancel the VOR during active head movements. Thus the signals produced by Pk cells in the floccular region are necessary for controlling smooth pursuit eye movements but not for coordinating gaze during active head movements. The results imply that individual functional modules in the cerebellar cortex are less involved in the global organization and coordination of movements than with parametric control of movements produced by a specific part of the body.

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.

Smooth pursuitlike eye movements evoked by microstimulation in macaque nucleus reticularis tegmenti pontis

1996 ◽  
Vol 76 (5) ◽  
pp. 3313-3324 ◽  
Author(s):  
T. Yamada ◽  
D. A. Suzuki ◽  
R. D. Yee
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Current Intensity ◽  
Image Motion ◽  
Eye Position ◽  
Smooth Pursuit Eye Movements ◽  
Pontine Nucleus ◽  
Nucleus Reticularis Tegmenti Pontis ◽  
Pursuit Eye Movements ◽  
Nucleus Reticularis

1. Smooth pursuitlike eye movements were evoked with low current microstimulation delivered to rostral portions of the nucleus reticularis tegmenti pontis (rNRTP) in alert macaques. Microstimulation sites were selected by the observation of modulations in single-cell firing rates that were correlated with periodic smoothpursuit eye movements. Current intensities ranged from 10 to 120 microA and were routinely < 40 microA. Microstimulation was delivered either in the dark with no fixation, 100 ms after a fixation target was extinguished, or during maintained fixation of a stationary or moving target. Evoked eye movements also were studied under open-loop conditions with the target image stabilized on the retina. 2. Eye movements evoked in the absence of a target rapidly accelerated to a constant velocity that was maintained for the duration of the microstimulation. Evoked eye speeds ranged from 3.7 to 23 deg/s and averaged 11 deg/s. Evoked eye speed appeared to be linearly related to initial eye position with a sensitivity to initial eye position that averaged 0.23 deg.s-1.deg-1. While some horizontal and oblique smooth eye movements were elicited, microstimulation resulted in upward eye movements in 89% of the sites. 3. Evoked eye speed was found to be dependent on microstimulation pulse frequency and current intensity. Within limits, evoked eye speed increased with increases in stimulation frequency or current intensity. For stimulation frequencies < 300–400 Hz, only smooth pursuit-like eye movements were evoked. At higher stimulation frequencies, accompanying saccades consistently were elicited. 4. Feedback of retinal image motion interacted with the evoked eye movements to decrease eye speed if the visual motion was in the opposite direction as the evoked, pursuit-like eye movements. 5. The results implicate rNRTP as part of the neuronal substrate that controls smooth-pursuit eye movements. NRTP appears to be divided functionally into a rostral, pursuit-related portion and a caudal, saccade-related area. rNRTP is a component of a corticopontocerebellar circuit that presumably involves the pursuit area of the frontal eye field and that parallels the middle and medial superior temporal cerebral cortical/dorsalateral pontine nucleus (MT/MST-DLPN-cerebellum) pathway known to be involved also with regulating smooth-pursuit eye movements.

scholarly journals Temporal dynamics of retinal and extraretinal signals in the FEFsem during smooth pursuit eye movements

2017 ◽  
Vol 117 (5) ◽  
pp. 1987-2003 ◽  
Author(s):  
Leah Bakst ◽  
Jérome Fleuriet ◽  
Michael J. Mustari
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Clustering Algorithm ◽  
Critical Role ◽  
Image Motion ◽  
Frontal Eye Field ◽  
Smooth Pursuit Eye Movements ◽  
Pursuit Eye Movements ◽  
Eye Field ◽  
Eye Velocity

Neurons in the smooth eye movement subregion of the frontal eye field (FEFsem) are known to play an important role in voluntary smooth pursuit eye movements. Underlying this function are projections to parietal and prefrontal visual association areas and subcortical structures, all known to play vital but differing roles in the execution of smooth pursuit. Additionally, the FEFsem has been shown to carry a diverse array of signals (e.g., eye velocity, acceleration, gain control). We hypothesized that distinct subpopulations of FEFsem neurons subserve these diverse functions and projections, and that the relative weights of retinal and extraretinal signals could form the basis for categorization of units. To investigate this, we used a step-ramp tracking task with a target blink to determine the relative contributions of retinal and extraretinal signals in individual FEFsem neurons throughout pursuit. We found that the contributions of retinal and extraretinal signals to neuronal activity and behavior change throughout the time course of pursuit. A clustering algorithm revealed three distinct neuronal subpopulations: cluster 1 was defined by a higher sensitivity to eye velocity, acceleration, and retinal image motion; cluster 2 had greater activity during blinks; and cluster 3 had significantly greater eye position sensitivity. We also performed a comparison with a sample of medial superior temporal neurons to assess similarities and differences between the two areas. Our results indicate the utility of simple tests such as the target blink for parsing the complex and multifaceted roles of cortical areas in behavior. NEW & NOTEWORTHY The frontal eye field (FEF) is known to play a critical role in volitional smooth pursuit, carrying a variety of signals that are distributed throughout the brain. This study used a novel application of a target blink task during step ramp tracking to determine, in combination with a clustering algorithm, the relative contributions of retinal and extraretinal signals to FEF activity and the extent to which these contributions could form the basis for a categorization of neurons.

Participation of Caudal Fastigial Nucleus in Smooth Pursuit Eye Movements. II. Effects of Muscimol Inactivation

1997 ◽  
Vol 78 (2) ◽  
pp. 848-859 ◽  
Author(s):  
Farrel R. Robinson ◽  
Andreas Straube ◽  
Albert F. Fuchs
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Constant Velocity ◽  
Rhesus Macaques ◽  
Aminobutyric Acid ◽  
Fastigial Nucleus ◽  
Target Velocity ◽  
Smooth Pursuit Eye Movements ◽  
Pursuit Eye Movements ◽  
Ventral Paraflocculus

Robinson, Farrel, R., Andreas Straube, and Albert F. Fuchs. Participation of the caudal fastigial nucleus in smooth pursuit eye movements. II. Effects of muscimol inactivation. J. Neurophysiol. 78: 848–859, 1997. We studied the effect of temporarily inactivating the caudal fastigial nucleus (CFN) in three rhesus macaques trained to make smooth pursuit eye movements. We injected the γ-aminobutyric acid A agonist muscimol into one or both CFNs where we had recorded pursuit-related neurons a few minutes earlier. Inactivating the CFN on one side impaired pursuit in one monkey so severely that it could not follow step-ramp targets moving at 20°/s, the target velocity that we used to test the other two monkeys. We tested this monkey with targets moving at 10°/s. In all three monkeys, unilateral CFN inactivation either increased the acceleration of ipsilateral step-ramp pursuit (in 2 monkeys, to 144 and 220% of normal) or decreased the acceleration of contralateral pursuit (in 1 monkey, to 71% of normal). Muscimol injected into both CFNs in two of the monkeys left both ipsilateral and contralateral acceleration nearly normal in both monkeys (101% of normal). Unilateral CFN inactivation also impaired the velocity of maintained pursuit as the monkeys tracked a target moving at a constant velocity or oscillating sinusoidally. Averaged across both types of movements in all three monkeys, gains for ipsilateral, contralateral, upward, and downward pursuit were 94, 67, 84, and 73% of normal, respectively. Unilateral CFN inactivation also impaired the monkeys' ability to suppress their vestibuloocular reflex (VOR). Averaged across the two monkeys VOR gain during suppression increased from 0.06 to 0.25 during yaw rotation and from 0.21 to 0.59 during pitch rotation. Bilateral CFN inactivation reduced pursuit gains in all directions more than unilateral injection did. In the two monkeys tested, ipsilateral, contralateral, upward, and downward gains went from 94, 86, 85, and 74% of normal, respectively, after we inactivated one CFN to 88, 73, 80, and 64% of normal after we also inactivated the second CFN. We can explain many, but not all, of the effects of CFN activation on smooth pursuit with the behavior of CFN neurons, and the assumption that the activity of each CFN neuron helps drive pursuit movements in the direction that best activates that neuron. We conclude that the CFN, like the flocculus-ventral paraflocculus, is a cerebellar region involved in control of smooth pursuit.

scholarly journals Signals That Modulate Gain Control for Smooth Pursuit Eye Movements in Monkeys

2004 ◽  
Vol 91 (2) ◽  
pp. 623-631 ◽  
Author(s):  
Megan R. Carey ◽  
Stephen G. Lisberger
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Target Motion ◽  
Smooth Pursuit Eye Movements ◽  
Velocity Signal ◽  
Adaptive Modification ◽  
The Gaze ◽  
Pursuit Eye Movements ◽  
Internal Gain ◽  
Vor Adaptation

The generation of primate smooth pursuit eye movements involves two processes. One process transforms the direction and speed of target motion into a motor command and the other regulates the strength, or “gain,” of the visual-motor transformation. We have conducted a behavioral analysis to identify the signals that modulate the internal gain of pursuit. To test whether the modulatory signals are related to eye velocity in the orbit or in the world (gaze velocity), we used brief perturbations of target motion to probe the gain of pursuit during tracking conditions that used head rotation to dissociate eye and gaze velocity. We found that the responses to perturbations varied primarily as a function of gaze velocity. To further understand the gaze velocity signals that control internal pursuit gain, we used adaptive modification of the gain of the vestibulo-ocular reflex (VOR) to dissociate physical gaze velocity from the component of gaze velocity that is driven by visual inputs. After VOR adaptation, perturbation responses were altered; the smallest perturbation responses now occurred during tracking conditions that required nonzero physical gaze velocity. However, perturbation responses during tracking conditions that mimicked the modified VOR were still enhanced relative to those obtained during fixation. We conclude that the signals that modulate the internal gain of pursuit are modified by VOR adaptation so that they are rendered intermediate between physical and visually driven gaze velocity. Similar changes in the gaze velocity signal have been reported in the cerebellar floccular complex following adaptive modification of the VOR and could be present in other brain areas that carry putative gaze velocity signals.

scholarly journals Role of Arcuate Frontal Cortex of Monkeys in Smooth Pursuit Eye Movements. I. Basic Response Properties to Retinal Image Motion and Position

2002 ◽  
Vol 87 (6) ◽  
pp. 2684-2699 ◽  
Author(s):  
Masaki Tanaka ◽  
Stephen G. Lisberger
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Retinal Image ◽  
Image Motion ◽  
Smooth Pursuit Eye Movements ◽  
Pursuit Eye Movements ◽  
Wide Range ◽  
Image Position ◽  
Eye Velocity ◽  
Pursuit Neurons

Anatomical and physiological studies have shown that the “frontal pursuit area” (FPA) in the arcuate cortex of monkeys is involved in the control of smooth pursuit eye movements. To further analyze the signals carried by the FPA, we examined the activity of pursuit-related neurons recorded from a discrete region near the arcuate spur during a variety of oculomotor tasks. Pursuit neurons showed direction tuning with a wide range of preferred directions and a mean full width at half-maximum of 129°. Analysis of latency using the “receiver operating characteristic” to compare responses to target motion in opposite directions showed that the directional response of 58% of FPA neurons led the initiation of pursuit, while 19% led by 25 ms or more. Analysis of neuronal responses during pursuit of a range of target velocities revealed that the sensitivity to eye velocity was larger during the initiation of pursuit than during the maintenance of pursuit, consistent with two components of firing related to image motion and eye motion. FPA neurons showed correlates of two behavioral features of pursuit documented in prior reports. 1) Eye acceleration at the initiation of pursuit declines as a function of the eccentricity of the moving target. FPA neurons show decreased firing at the initiation of pursuit in parallel with the decline in eye acceleration. This finding is consistent with prior suggestions that the FPA plays a role in modulating the gain of visual-motor transmission for pursuit. 2) A stationary eccentric cue evokes a smooth eye movement opposite in direction to the cue and enhances the pursuit evoked by subsequent target motions. Many pursuit neurons in the FPA showed weak, phasic visual responses for stationary targets and were tuned for the positions about 4° eccentric on the side opposite to the preferred pursuit direction. However, few neurons (12%) responded during the preparation or execution of saccades. The responses to the stationary target could account for the behavioral effects of stationary, eccentric cues. Further analysis of the relationship between firing rate and retinal position error during pursuit in the preferred and opposite directions failed to provide evidence for a large contribution of image position to the firing of FPA neurons. We conclude that FPA processes information in terms of image and eye velocity and that it is functionally separate from the saccadic frontal eye fields, which processes information in terms of retinal image position.

scholarly journals Do we have direct access to retinal image motion during smooth pursuit eye movements?

2009 ◽  
Vol 9 (1) ◽  
pp. 33-33 ◽  
Author(s):  
T. C. A. Freeman ◽  
R. A. Champion ◽  
J. H. Sumnall ◽  
R. J. Snowden
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Retinal Image ◽  
Image Motion ◽  
Direct Access ◽  
Smooth Pursuit Eye Movements ◽  
Pursuit Eye Movements ◽  
Retinal Image Motion
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