The effects of frontal eye field and dorsomedial frontal cortex lesions on visually guided eye movements

10.1038/693 ◽  
1998 ◽  
Vol 1 (3) ◽  
pp. 248-253 ◽  
Author(s):  
Peter H. Schiller ◽  
I-han Chou
Keyword(s):  
Eye Movements ◽  
Frontal Cortex ◽  
Frontal Eye Field ◽  
Visually Guided ◽  
Dorsomedial Frontal Cortex ◽  
Eye Field

Suppression of Task-Related Saccades by Electrical Stimulation in the Primate's Frontal Eye Field

1997 ◽  
Vol 77 (5) ◽  
pp. 2252-2267 ◽  
Author(s):  
Douglas D. Burman ◽  
Charles J. Bruce
Keyword(s):  
Electrical Stimulation ◽  
Eye Movements ◽  
Frontal Lobe ◽  
Premotor Cortex ◽  
Saccadic Eye Movements ◽  
Association Cortex ◽  
Frontal Eye Field ◽  
Visually Guided ◽  
Low Intensity ◽  
Eye Field

Burman, Douglas D. and Charles J. Bruce. Suppression of task-related saccades by electrical stimulation in the primate's frontal eye field. J. Neurophysiol. 77: 2252–2267, 1997. Patients with frontal lobe damage have difficulty suppressing reflexive saccades to salient visual stimuli, indicating that frontal lobe neocortex helps to suppress saccades as well as to produce them. In the present study, a role for the frontal eye field (FEF) in suppressing saccades was demonstrated in macaque monkeys by application of intracortical microstimulation during the performance of a visually guided saccade task, a memory prosaccade task, and a memory antisaccade task. A train of low-intensity (20–50 μA) electrical pulses was applied simultaneously with the disappearance of a central fixation target, which was always the cue to initiate a saccade. Trials with and without stimulation were compared, and significantly longer saccade latencies on stimulation trials were considered evidence of suppression. Low-intensity stimulation suppressed task-related saccades at 30 of 77 sites tested. In many cases saccades were suppressed throughout the microstimulation period (usually 450 ms) and then executed shortly after the train ended. Memory-guided saccades were most dramatically suppressed and were often rendered hypometric, whereas visually guided saccades were less severely suppressed by stimulation. At 18 FEF sites, the suppression of saccades was the only observable effect of electrical stimulation. Contraversive saccades were usually more strongly suppressed than ipsiversive ones, and cells recorded at such purely suppressive sites commonly had either foveal receptive fields or postsaccadic responses. At 12 other FEF sites at which saccadic eye movements were elicited at low thresholds, task-related saccades whose vectors differed from that of the electrically elicited saccade were suppressed by electrical stimulation. Such suppression at saccade sites was observed even with currents below the threshold for eliciting saccades. Pure suppression sites tended to be located near or in the fundus, deeper in the anterior bank of the arcuate than elicited saccade sites. Stimulation in the prefrontal association cortex anterior to FEF did not suppress saccades, nor did stimulation in premotor cortex posterior to FEF. These findings indicate that the primate FEF can help orchestrate saccadic eye movements by suppressing inappropriate saccade vectors as well as by selecting, specifying, and triggering appropriate saccades. We hypothesize that saccades could be suppressed both through local FEF interactions and through FEF projections to subcortical regions involved in maintaining fixation.

Muscimol-Induced Inactivation of Monkey Frontal Eye Field: Effects on Visually and Memory-Guided Saccades

1999 ◽  
Vol 81 (5) ◽  
pp. 2191-2214 ◽  
Author(s):  
Elisa C. Dias ◽  
Mark A. Segraves
Keyword(s):  
Eye Movements ◽  
Target Location ◽  
Memory Task ◽  
Saccadic Eye Movements ◽  
Spatial Location ◽  
Frontal Eye Field ◽  
Visually Guided ◽  
Field Effects ◽  
Progressive Loss ◽  
Eye Field

Muscimol-induced inactivation of the monkey frontal eye field: effects on visually and memory-guided saccades. Although neurophysiological, anatomic, and imaging evidence suggest that the frontal eye field (FEF) participates in the generation of eye movements, chronic lesions of the FEF in both humans and monkeys appear to cause only minor deficits in visually guided saccade generation. Stronger effects are observed when subjects are tested in tasks with more cognitive requirements. We tested oculomotor function after acutely inactivating regions of the FEF to minimize the effects of plasticity and reallocation of function after the loss of the FEF and gain more insight into the FEF contribution to the guidance of eye movements in the intact brain. Inactivation was induced by microinjecting muscimol directly into physiologically defined sites in the FEF of three monkeys. FEF inactivation severely impaired the monkeys’ performance of both visually guided and memory-guided saccades. The monkeys initiated fewer saccades to the retinotopic representation of the inactivated FEF site than to any other location in the visual field. The saccades that were initiated had longer latencies, slower velocities, and larger targeting errors than controls. These effects were present both for visually guided and for memory-guided saccades, although the memory-guided saccades were more disrupted. Initially, the effects were restricted spatially, concentrating around the retinotopic representation at the center of the inactivated site, but, during the course of several hours, these effects spread to flanking representations. Predictability of target location and motivation of the monkey also affected saccadic performance. For memory-guided saccades, increases in the time during which the monkey had to remember the spatial location of a target resulted in further decreases in the accuracy of the saccades and in smaller peak velocities, suggesting a progressive loss of the capacity to maintain a representation of target location in relation to the fovea after FEF inactivation. In addition, the monkeys frequently made premature saccades to targets in the hemifield ipsilateral to the injection site when performing the memory task, indicating a deficit in the control of fixation that could be a consequence of an imbalance between ipsilateral and contralateral FEF activity after the injection. There was also a progressive loss of fixation accuracy, and the monkeys tended to restrict spontaneous visual scanning to the ipsilateral hemifield. These results emphasize the strong role of the FEF in the intact monkey in the generation of all voluntary saccadic eye movements, as well as in the control of fixation.

Neural responses related to smooth-pursuit eye movements and their correspondence with electrically elicited smooth eye movements in the primate frontal eye field

1994 ◽  
Vol 72 (4) ◽  
pp. 1634-1653 ◽  
Author(s):  
J. P. Gottlieb ◽  
M. G. MacAvoy ◽  
C. J. Bruce
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Gaussian Function ◽  
Weighted Average ◽  
Frontal Eye Field ◽  
Visually Guided ◽  
Directional Tuning ◽  
Eye Field ◽  
Pursuit Velocity ◽  
Pursuit Neurons

1. Intracortical microstimulation of a portion of the monkey frontal eye field (FEF) lying in the floor and posterior bank of the arcuate sulcus evokes smooth, rather than saccadic eye movements. To further explore this region's involvement in pursuit, we recorded from FEF neurons in the vicinity of sites from which smooth eye movements (SEMs) were elicited electrically and studied their responses during smooth-pursuit and saccadic tasks. In this report, we describe the neurons' responses during visually guided smooth pursuit and compare their locations and response properties with those of elicited SEMs. 2. One hundred and ninety-three neurons, recorded from the FEF region in six hemispheres of three rhesus monkeys, were classified as “pursuit neurons”. These neurons responded during smooth-pursuit tracking of moving visual stimuli but had no, or only minimal, responses in conjunction with visually guided saccades. Pursuit neurons were located in a small region of the arcuate fundus and posterior bank that overlapped, and extended slightly beyond, the region from which SEMs were elicited with microstimulation. 3. All pursuit neurons had a preferred pursuit direction, and all directions were represented with no strong bias toward ipsilateral, contralateral, up, or down. The directional tuning of 80 pursuit cells was measured quantitatively by testing pursuit in several directions and fitting the responses to a Gaussian function. Tuning indices (the sigma parameter of the Gaussian fit) varied between 13 degrees and 136 degrees. The median tuning index, 44.5 degrees, corresponds to a full width at half maximum of 105 degrees. The ubiquity of selectivity for pursuit direction and the wide distribution of preferred directions indicates that pursuit direction uses a place-code type of representation in FEF; however, the broad directional tuning of most neurons suggests that pursuit direction is given by a weighted average of optimal directions across the population of pursuit neurons active at any given time. 4. In general, the responses of pursuit neurons increased with pursuit velocity. Of 13 neurons formally tested with 2 s of constant-velocity tracking in their preferred direction across a range of target speeds, pursuit velocity sensitivity ranged from 0.24 to 1.42 spikes.s-1.deg-1.s-1, with an average sensitivity of 0.70. This relationship suggests that pursuit neurons represent pursuit magnitude using a rate code; this parallels our previous observation that at most SEM sites, the velocity and acceleration of the electrically elicited eye movements increased as a function of the stimulation current.(ABSTRACT TRUNCATED AT 400 WORDS)

Saccade initiation and latency deficits after combined lesions of the frontal and posterior eye fields in monkeys

1992 ◽  
Vol 68 (5) ◽  
pp. 1913-1916 ◽  
Author(s):  
J. C. Lynch
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Frontal Eye Field ◽  
Visually Guided ◽  
Before And After ◽  
Combined Lesions ◽  
Eye Field ◽  
Bilateral Lesions

1. Monkeys were trained to perform horizontal visually guided saccades. Latency was measured before and after bilateral lesions of the frontal eye field (FEF) and after combined lesions of both the FEF and the posterior eye field. Destruction of either of these regions alone causes only modest deficits of eye movement, but destruction of both together produces profound oculomotor impairment. The results support the proposal that purposeful eye movements are controlled by a distributed corticocortical network that includes nodes in frontal and parieto-occipital regions.

scholarly journals The effects of anterior arcuate and dorsomedial frontal cortex lesions on visually guided eye movements in the rhesus monkey:

2000 ◽  
Vol 40 (10-12) ◽  
pp. 1609-1626 ◽  
Author(s):  
Peter H Schiller ◽  
I-han Chou
Keyword(s):  
Eye Movements ◽  
Rhesus Monkey ◽  
Frontal Cortex ◽  
Visually Guided ◽  
Dorsomedial Frontal Cortex

scholarly journals Visual sensitivity of frontal eye field neurons during the preparation of saccadic eye movements

2016 ◽  
Vol 116 (6) ◽  
pp. 2882-2891 ◽  
Author(s):  
Rebecca M. Krock ◽  
Tirin Moore
Keyword(s):  
Visual Cortex ◽  
Eye Movements ◽  
Saccadic Eye Movements ◽  
Visual Sensitivity ◽  
Saccadic Suppression ◽  
Frontal Eye Field ◽  
Visually Guided ◽  
Visual Neurons ◽  
Saccade Onset ◽  
Eye Field

Primate vision is continuously disrupted by saccadic eye movements, and yet this disruption goes unperceived. One mechanism thought to reduce perception of this self-generated movement is saccadic suppression, a global loss of visual sensitivity just before, during, and after saccadic eye movements. The frontal eye field (FEF) is a candidate source of neural correlates of saccadic suppression previously observed in visual cortex, because it contributes to the generation of visually guided saccades and modulates visual cortical responses. However, whether the FEF exhibits a perisaccadic reduction in visual sensitivity that could be transmitted to visual cortex is unknown. To determine whether the FEF exhibits a signature of saccadic suppression, we recorded the visual responses of FEF neurons to brief, full-field visual probe stimuli presented during fixation and before onset of saccades directed away from the receptive field in rhesus macaques ( Macaca mulatta). We measured visual sensitivity during both epochs and found that it declines before saccade onset. Visual sensitivity was significantly reduced in visual but not visuomotor neurons. This reduced sensitivity was also present in visual neurons with no movement-related modulation during visually guided saccades and thus occurred independently from movement-related activity. Across the population of visual neurons, sensitivity began declining ∼80 ms before saccade onset. We also observed a similar presaccadic reduction in sensitivity to isoluminant, chromatic stimuli. Our results demonstrate that the signaling of visual information by FEF neurons is reduced during saccade preparation, and thus these neurons exhibit a signature of saccadic suppression.

scholarly journals Neural correlations are attenuated in the transformation from the frontal cortex to movement

2021 ◽  
Author(s):  
Noga Larry ◽  
Mati Joshua
Keyword(s):  
Eye Movements ◽  
Frontal Cortex ◽  
Frontal Eye Field ◽  
Neuronal Responses ◽  
Distance Metric ◽  
Motor Pathway ◽  
Pursuit Eye Movements ◽  
Correlated Activity ◽  
Eye Field ◽  
Novel Method

Correlated activity between neurons can cause variability in behavior across trials. The extent to which correlated activity affects behavior depends on the properties of its translation into movement. We developed a novel method that estimates the contribution of correlations in the frontal eye field (FEF) to pursuit eye movements. We defined a distance metric between the behavior on different trials. Based on this metric, we applied a sequence of shuffles to the neuronal responses, allowing trials to be matched with increasingly distant trials. Correlations between neurons were strongly attenuated when applying even the most constrained shuffle. Thus, only a small fraction of FEF correlations affects the behavior. We used simulations to validate our approach and demonstrate its generalizability over different models. We show that the attenuation of correlated activity through the motor pathway could stem from the interplay between the structure of the correlations and the decoder of FEF activity.

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