Suppression of Visually and Memory-Guided Saccades Induced by Electrical Stimulation of the Monkey Frontal Eye Field. I. Suppression of Ipsilateral Saccades

2004 ◽  
Vol 92 (4) ◽  
pp. 2248-2260 ◽  
Author(s):  
Yoshiko Izawa ◽  
Hisao Suzuki ◽  
Yoshikazu Shinoda
Keyword(s):  
Electrical Stimulation ◽  
Visual Fixation ◽  
Frontal Eye Field ◽  
Visually Guided ◽  
Stimulation Site ◽  
Efferent Pathway ◽  
Saccade Onset ◽  
Eye Field ◽  
Interesting Object ◽  
Stimulation Of

When a saccade occurs to an interesting object, visual fixation holds its image on the fovea and suppresses saccades to other objects. Electrical stimulation of the frontal eye field (FEF) has been reported to elicit saccades, and recently also to suppress saccades. This study was performed to characterize properties of the suppression of visually guided (Vsacs) and memory-guided saccades (Msacs) induced by electrical stimulation of the FEF in trained monkeys. For any given stimulation site, we determined the threshold for electrically evoked saccades (Esacs) at ≤50 μA and then examined suppressive effects of stimulation at the same site on Vsacs and Msacs. FEF stimulation suppressed the initiation of both Vsacs and Msacs during and about 50 ms after stimulation at stimulus intensities lower than those for eliciting Esacs, but did not affect the vector of these saccades. Suppression occurred for ipsiversive but not contraversive saccades, and more strongly for saccades with larger amplitudes and those with initial eye positions shifted more in the saccadic direction. The most effective stimulation timing for suppression was about 50 ms before saccade onset, which suggests that suppression occurred in the efferent pathway for generating Vsacs at the premotor rather than the motoneuronal level, most probably in the superior colliculus and/or the paramedian pontine reticular formation. Suppression sites of ipsilateral saccades were distributed over the classical FEF where saccade-related movement neurons were observed. The results suggest that the FEF may play roles in not only generating contraversive saccades but also maintaining visual fixation by suppressing ipsiversive saccades.

Suppression of Visually and Memory-Guided Saccades Induced by Electrical Stimulation of the Monkey Frontal Eye Field. II. Suppression of Bilateral Saccades

2004 ◽  
Vol 92 (4) ◽  
pp. 2261-2273 ◽  
Author(s):  
Yoshiko Izawa ◽  
Hisao Suzuki ◽  
Yoshikazu Shinoda
Keyword(s):  
Electrical Stimulation ◽  
Superior Colliculus ◽  
Reticular Formation ◽  
Neural Mechanism ◽  
Frontal Eye Field ◽  
Pontine Reticular Formation ◽  
Visually Guided ◽  
Saccade Onset ◽  
Eye Field ◽  
Stimulation Of

To understand the neural mechanism of fixation, we investigated effects of electrical stimulation of the frontal eye field (FEF) and its vicinity on visually guided (Vsacs) and memory-guided saccades (Msacs) in trained monkeys and found that there were two types of suppression induced by the electrical stimulation: suppression of ipsilateral saccades and suppression of bilateral saccades. In this report, we characterized the properties of the suppression of bilateral Vsacs and Msacs. Stimulation of the bilateral suppression sites suppressed the initiation of both Vsacs and Msacs in all directions during and ∼50 ms after stimulation but did not affect the vector of these saccades. The suppression was stronger for ipsiversive larger saccades and contraversive smaller saccades, and saccades with initial eye positions shifted more in the saccadic direction. The most effective stimulation timing for the suppression of ipsilateral and contralateral Vsacs was ∼40–50 ms before saccade onset, indicating that the suppression occurred most likely in the superior colliculus and/or the paramedian pontine reticular formation. Suppression sites of bilateral saccades were located in the prearcuate gyrus facing the inferior arcuate sulcus where stimulation induced suppression at ≤40 μA but usually did not evoke any saccades at 80 μA and were different from those of ipsilateral saccades where stimulation evoked saccades at ≤50 μA. The bilateral suppression sites contained fixation neurons. The results suggest that fixation neurons in the bilateral suppression area of the FEF may play roles in maintaining fixation by suppressing saccades in all directions.

Response Properties of Fixation Neurons and Their Location in the Frontal Eye Field in the Monkey

2009 ◽  
Vol 102 (4) ◽  
pp. 2410-2422 ◽  
Author(s):  
Yoshiko Izawa ◽  
Hisao Suzuki ◽  
Yoshikazu Shinoda
Keyword(s):  
Electrical Stimulation ◽  
Frontal Eye Field ◽  
Visually Guided ◽  
Related Activity ◽  
Strong Suppression ◽  
Steady Fixation ◽  
Eye Field ◽  
Suppression Mechanism ◽  
Attentive Fixation ◽  
Stimulation Of

Electrical stimulation of the frontal eye field (FEF) has recently been reported to suppress the generation of saccades, which supports the idea that the FEF plays a role in maintaining attentive fixation. This study analyzed the activity of fixation neurons that discharged during fixation in the FEF in relation to visual fixation and saccades in trained monkeys. The neural activity of fixation neurons increased at the start of fixation and was maintained during fixation. When a fixation spot of light disappeared during steady fixation, different fixation neurons exhibited different categories of response, ranging from a decrease in activity to an increase in activity, indicating that there is a continuum of fixation neurons, from neurons with foveal visual-related activity to neurons with activity that is related to the motor act of fixating. Fixation neurons usually showed a decrease in their firing rate before the onset of visually guided saccades (Vsacs) and memory-guided saccades in any direction. The reduction in activity of fixation neurons nearly coincided with, or occurred slightly before, the increase in the activity of saccade-related movement neurons in the FEF in the same monkey. Although fixation neurons were scattered in the FEF, about two thirds of fixation neurons were concentrated in a localized area in the FEF at which electrical stimulation induced strong suppression of the initiation of Vsacs bilaterally. These results suggest that fixation neurons in the FEF are part of a suppression mechanism that could control the maintenance of fixation and the initiation of saccades.

Activity of monkey frontal eye field neurons projecting to oculomotor regions of the pons

1992 ◽  
Vol 68 (6) ◽  
pp. 1967-1985 ◽  
Author(s):  
M. A. Segraves
Keyword(s):  
Electrical Stimulation ◽  
Visual Stimulation ◽  
Saccadic Eye Movements ◽  
Frontal Eye Field ◽  
Related Activity ◽  
Burst Neurons ◽  
Eye Field ◽  
Movement Field ◽  
Omnipause Neurons ◽  
Stimulation Of

1. This study identified neurons in the rhesus monkey's frontal eye field that projected to oculomotor regions of the pons and characterized the signals sent by these neurons from frontal eye field to pons. 2. In two behaving rhesus monkeys, frontal eye field neurons projecting to the pons were identified via antidromic excitation by a stimulating microelectrode whose tip was centered in or near the omnipause region of the pontine raphe. This stimulation site corresponded to the nucleus raphe interpositus (RIP). In addition, electrical stimulation of the frontal eye field was used to demonstrate the effects of frontal eye field input on neurons in the omnipause region and surrounding paramedian pontine reticular formation (PPRF). 3. Twenty-five corticopontine neurons were identified and characterized. Most frontal eye field neurons projecting to the pons were either movement neurons, firing in association with saccadic eye movements (48%), or foveal neurons responsive to visual stimulation of the fovea combined with activity related to fixation (28%). Corticopontine movement neurons fired before, during, and after saccades made within a restricted movement field. 4. The activity of identified corticopontine neurons was very similar to the activity of neurons antidromically excited from the superior colliculus where 59% had movement related activity, and 22% had foveal and fixation related activity. 5. High-intensity, short-duration electrical stimulation of the frontal eye field caused omnipause neurons to stop firing. The cessation in firing appeared to be immediate, within < or = 5 ms. The time that the omnipause neuron remained quiet depended on the intensity of the cortical stimulus and lasted up to 30 ms after a train of three stimulus pulses lasting a total of 6 ms at an intensity of 1,000 microA. Low-intensity, longer duration electrical stimuli (24 pulses, 75 microA, 70 ms) traditionally used to evoke saccades from the frontal eye field were also followed by a cessation in omnipause neuron firing, but only after a delay of approximately 30 ms. For these stimuli, the omnipause neuron resumed firing when the stimulus was turned off. 6. The same stimuli that caused omnipause neurons to stop firing excited burst neurons in the PPRF. The latency to excitation ranged from 4.2 to 9.8 ms, suggesting that there is at least one additional neuron between frontal eye field neurons and burst neurons in the PPRF. 7. The present study confirms and extends the results of previous work, with the use of retrograde and anterograde tracers, demonstrating direct projections from the frontal eye field to the pons.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Electrical Stimulation of the Frontal Eye Field in a Monkey Produces Combined Eye and Head Movements

2000 ◽  
Vol 84 (2) ◽  
pp. 1103-1106 ◽  
Author(s):  
Tyson A. Tu ◽  
E. Gregory Keating
Keyword(s):  
Electrical Stimulation ◽  
Eye Movements ◽  
Head Movements ◽  
Frontal Eye Field ◽  
Gaze Shifts ◽  
Gaze Shift ◽  
Eye Field ◽  
A Site ◽  
Head Rotations ◽  
Stimulation Of

The frontal eye field (FEF), an area in the primate frontal lobe, has long been considered important for the production of eye movements. Past studies have evoked saccade-like movements from the FEF using electrical stimulation in animals that were not allowed to move their heads. Using electrical stimulation in two monkeys that were free to move their heads, we have found that the FEF produces gaze shifts that are composed of both eye and head movements. Repeated stimulation at a site evoked gaze shifts of roughly constant amplitude. However, that gaze shift could be accomplished with varied amounts of head and eye movements, depending on their (head and eye) respective starting positions. This evidence suggests that the FEF controls visually orienting movements using both eye and head rotations rather than just shifting the eyes as previously thought.

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.

scholarly journals Frontal Eye Field Neurons Orthodromically Activated From the Superior Colliculus

1998 ◽  
Vol 80 (6) ◽  
pp. 3331-3335 ◽  
Author(s):  
Marc A. Sommer ◽  
Robert H. Wurtz
Keyword(s):  
Electrical Stimulation ◽  
Superior Colliculus ◽  
Direct Evidence ◽  
Visual Stimulation ◽  
Saccadic Eye Movements ◽  
Frontal Eye Field ◽  
Anatomical Studies ◽  
Eye Field ◽  
To Receive ◽  
Stimulation Of

Sommer, Marc A. and Robert H. Wurtz. Frontal eye field neurons orthodromically activated from the superior colliculus. J. Neurophysiol. 80: 3331–3333, 1998. Anatomical studies have shown that the frontal eye field (FEF) and superior colliculus (SC) of monkeys are reciprocally connected, and a physiological study described the signals sent from the FEF to the SC. Nothing is known, however, about the signals sent from the SC to the FEF. We physiologically identified and characterized FEF neurons that are likely to receive input from the SC. Fifty-two FEF neurons were found that were orthodromically activated by electrical stimulation of the intermediate or deeper layers of the SC. All the neurons that we tested ( n = 34) discharged in response to visual stimulation. One-half also discharged when saccadic eye movements were made. This provides the first direct evidence that the ascending pathway from SC to FEF might carry visual- and saccade-related signals. Our findings support a hypothesis that the SC and the FEF interact bidirectionally during the events leading up to saccade generation.

Suppression of smooth pursuit eye movements induced by electrical stimulation of the monkey frontal eye field

2011 ◽  
Vol 106 (5) ◽  
pp. 2675-2687 ◽  
Author(s):  
Yoshiko Izawa ◽  
Hisao Suzuki ◽  
Yoshikazu Shinoda
Keyword(s):  
Electrical Stimulation ◽  
Smooth Pursuit ◽  
Suppressive Effect ◽  
Frontal Eye Field ◽  
Pursuit Eye Movements ◽  
Physiological Properties ◽  
Eye Field ◽  
Catch Up ◽  
Stimulation Of

This study was performed to characterize the properties of the suppression of smooth pursuit eye movement induced by electrical stimulation of the frontal eye field (FEF) in trained monkeys. At the stimulation sites tested, we first determined the threshold for generating electrically evoked saccades (Esacs). We then examined the suppressive effects of stimulation on smooth pursuit at intensities that were below the threshold for eliciting Esacs. We observed that FEF stimulation induced a clear deceleration of pursuit at pursuit initiation and also during the maintenance of pursuit at subthreshold intensities. The suppression of pursuit occurred even in the absence of catch-up saccades during pursuit, indicating that suppression influenced pursuit per se. We mapped the FEF area that was associated with the suppressive effect of stimulation on pursuit. In a wide area in the FEF, suppressive effects were observed for ipsiversive, but not contraversive, pursuit. In contrast, we observed the bilateral suppression of both ipsiversive and contraversive pursuit in a localized area in the FEF. This area coincided with the area in which we have previously shown that stimulation suppressed the generation of saccades in bilateral directions and also where fixation neurons that discharged during fixation were concentrated. On the basis of these results, we compared the FEF suppression of pursuit with that of saccades with regard to several physiological properties and then discussed the role of the FEF in the suppression of both pursuit and saccades, and particularly in the maintenance of visual fixation.

scholarly journals Suppressive control of optokinetic and vestibular nystagmus by the primate frontal eye field

2020 ◽  
Vol 124 (3) ◽  
pp. 691-702
Author(s):  
Yoshiko Izawa ◽  
Hisao Suzuki
Keyword(s):  
Electrical Stimulation ◽  
Eye Movements ◽  
Visual Fixation ◽  
Frontal Eye Field ◽  
Vestibular Nystagmus ◽  
Functional Classes ◽  
Eye Field ◽  
Neuronal Assembly

In this study, electrical stimulation in the frontal eye field (FEF) suppressed the quick and slow phases of optokinetic and vestibular nystagmus at an intensity subthreshold for eliciting saccades. Furthermore, the activity of fixation neurons in the FEF was related to the suppression of optokinetic and vestibular nystagmus by visual fixation. This suggests that a common neuronal assembly in the FEF may contribute to the suppressive control of different functional classes of eye movements.

scholarly journals Substantia Nigra Stimulation Influences Monkey Superior Colliculus Neuronal Activity Bilaterally

2008 ◽  
Vol 100 (2) ◽  
pp. 1098-1112 ◽  
Author(s):  
Ping Liu ◽  
Michele A. Basso
Keyword(s):  
Electrical Stimulation ◽  
Substantia Nigra ◽  
Superior Colliculus ◽  
Time Course ◽  
Discharge Rate ◽  
Onset Time ◽  
Visually Guided ◽  
Alert Monkey ◽  
Saccade Onset ◽  
Stimulation Of

The inhibitory drive arising from the basal ganglia is thought to prevent the occurrence of orienting movements of the eyes, head, and body in monkeys and other mammals. The direct projection from the substantia nigra pars reticulata (SNr) to the superior colliculus (SC) mediates the inhibition. Since the original experiments in the SNr of monkeys the buildup or prelude neuron has been a focus of SC research. However, whether the SNr influences buildup neurons in SC is unknown. Furthermore, a contralateral SNr–SC pathway is evident in many species but remains unexplored in the alert monkey. Here we introduced electrical stimulation of one or both SNr nuclei while recording from SC buildup neurons. Stimulation of the SNr reduced the discharge rate of SC buildup neurons bilaterally. This result is consistent with activation of an inhibitory drive from SNr to SC. The time course of the influence of ipsilateral SNr on the activity of most SC neurons was longer (∼73 ms) than the influence of the contralateral SNr (∼34 ms). We also found that the variability of saccade onset time and saccade direction was altered with electrical stimulation of the SNr. Taken together our results show that electrical stimulation activates the inhibitory output of the SNr that in turn, reduces the activity of SC buildup neurons in both hemispheres. However, rather than acting as a gate for saccade initiation, the results suggest that the influence of SNr inhibition on visually guided saccades is more subtle, shaping the balance of excitation and inhibition across the SC.

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