Activity of omnipause neurons in alert cats during saccadic eye movements and visual stimuli

1982 ◽  
Vol 47 (5) ◽  
pp. 827-844 ◽  
Author(s):  
C. Evinger ◽  
C. R. Kaneko ◽  
A. F. Fuchs
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Visual Stimuli ◽  
Pause Duration ◽  
Visual Input ◽  
Transient Increase ◽  
Abducens Nucleus ◽  
Wide Range ◽  
Area Centralis ◽  
Omnipause Neurons

1. In the cats trained to follow a target spot with their eyes, activity was recorded from omnipause neurons (OPNs). OPNs discharge at a relatively high steady tonic rate (50-130 spikes/s) during visual fixation and smooth-pursuit eye movements but exhibit a complete cessation of discharge that begins before saccades in any direction. They are located in a compact region of the dorsal pontine tegmentum near the midline, just rostral to the abducens nucleus. 2. The average duration of the horizontal or vertical component of a saccade increases monotonically with pause duration, but a given pause duration is associated with a large range of individual saccade parameters and the timing of the pause, such as the latency from the pause onset to saccade onset or the interval from the maximum saccade velocity to the end of the pause, is no better. However, OPNs can be divided into two distinct groups on the basis of the timing of the pause relative to the parameters of the saccade. One group ceases discharging 32.4 +/- 4.6 ms, on average, before the saccade, while the second pauses 18.2 +/- 3.4 ms before the saccade. 3. Microstimulation at the site of OPNs affects the occurrence and trajectory of saccades but not smooth pursuit or fixation. Sustained electrical stimulation (20 micro A) lasting several seconds prevents the occurrence of saccades while brief trains (10-60 ms), timed to occur early in the saccade, interrupt it in midflight for the duration of the train. The latency to the interruption is about 26 ms. These data support the view that OPNs tonically inhibit the saccadic machinery between saccades and must be turned off to allow a saccade to occur. 4. Almost every (65 of 69) feline OPN exhibited a brief transient increase in activity for visual stimuli moving in any direction with a wide range of velocities. A moving 1 degree spot was generally more effective than a moving full-field, striped background. All units also showed a transient increase in firing when the spot was turned either on or off. Receptive fields plotted with the spot were greater than 250 deg2 and always included the area centralis. Two-thirds of the cells tested also responded to auditory stimuli. 5. Interaction between the excitatory visual input and the saccade-related pause was tested by comparing OPN activity and the saccadic trajectory during eye movements in the dark versus the light and by presenting brief flashes of light during a saccade. During saccades in the dark, the steady firing of OPNs was less than during saccades in the light. Only by stabilizing a flashed spot of light to occur on the area centralis at the beginning of the saccade was it possible to activate an OPN artificially to interrupt the saccade in midflight. Therefore, rather than being instrumental in specifically controlling the saccade trajectory, the visual input, along with the auditory and other sensory inputs, probably serves, under normal visual conditions, to help establish the tonic rate of OPNs. 6...

Common Inhibitory Mechanism for Saccades and Smooth-Pursuit Eye Movements

2002 ◽  
Vol 88 (4) ◽  
pp. 1880-1892 ◽  
Author(s):  
M. Missal ◽  
E. L. Keller
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Statistical Significance ◽  
Smooth Pursuit Eye Movements ◽  
Inhibitory Mechanism ◽  
Inhibitory System ◽  
Electrical Microstimulation ◽  
Pursuit Eye Movements ◽  
Premotor Neurons ◽  
Omnipause Neurons

The premotor pathways subserving saccades and smooth-pursuit eye movements are usually thought to be different. Indeed, saccade and smooth-pursuit eye movements have different dynamics and functions. In particular, a group of midline cells in the pons called omnipause neurons (OPNs) are considered to be part of the saccadic system only. It has been established that OPNs keep premotor neurons for saccades under constant inhibition during fixation periods. Saccades occur only when the activity of OPNs has completely stopped or paused. Accordingly, electrical stimulation in the region of OPNs inhibits premotor neurons and interrupts saccades. The premotor relay for smooth pursuit is thought to be organized differently and omnipause neurons are not supposed to be involved in smooth-pursuit eye movements. To investigate this supposition, OPNs were recorded during saccades and during smooth pursuit in the monkey ( Macaca mulatta). Unexpectedly, we found that neuronal activity of OPNs decreased during smooth pursuit. The resulting activity reduction reached statistical significance in ∼50% of OPNs recorded during pursuit of a target moving at 40°/s. On average, activity was reduced by 34% but never completely stopped or paused. The onset of activity reduction coincided with the onset of smooth pursuit. The duration of activity reduction was correlated with pursuit duration and its intensity was correlated with eye velocity. Activity reduction was observed even in the absence of catch-up saccades that frequently occur during pursuit. Electrical microstimulation in the OPNs' area induced a strong deceleration of the eye during smooth pursuit. These results suggest that OPNs form an inhibitory mechanism that could control the time course of smooth pursuit. This inhibitory mechanism is part of the fixation system and is probably needed to avoid reflexive eye movements toward targets that are not purposefully selected. This study shows that saccades and smooth pursuit, although they are different kinds of eye movements, are controlled by the same inhibitory system.

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.

Discharge patterns of neurons in the pretectal nucleus of the optic tract (NOT) in the behaving primate

1990 ◽  
Vol 64 (1) ◽  
pp. 77-90 ◽  
Author(s):  
M. J. Mustari ◽  
A. F. Fuchs
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Visual Stimuli ◽  
Receptive Fields ◽  
Optic Tract ◽  
Large Field ◽  
Smooth Pursuit Eye Movements ◽  
Stimulus Velocity ◽  
Pursuit Eye Movements ◽  
Pretectal Nucleus

1. To determine the possible role of the primate pretectal nucleus of the optic tract (NOT) in the generation of optokinetic and smooth-pursuit eye movements, we recorded the activity of 155 single units in four behaving rhesus macaques. The monkeys were trained to fixate a stationary target spot during visual testing and to track a small moving spot in a variety of visual environments. 2. The majority (82%) of NOT neurons responded only to visual stimuli. Most units responded vigorously for large-field (70 x 50 degrees) moving visual stimuli and responded less, if at all, during smooth-pursuit eye movements in the dark; many of these units had large receptive fields (greater than 10 x 10 degrees) that included the fovea. The remaining visual units responded more vigorously during smooth-pursuit eye movements in the dark than during movement of large-field visual stimuli; all but one had small receptive fields (less than 10 x 10 degrees) that included the fovea. For all visual units that responded during smooth pursuit, extinction of the small moving target so briefly that pursuit continued caused the firing rates to drop to resting levels, confirming that the discharge was due to visual stimulation of receptive fields with foveal and perifoveal movement sensitivity and not to smooth-pursuit eye movements per se. 3. Eighteen percent of all NOT units ceased their tonic discharge in association with all saccades including the quick phases accompanying optokinetic or vestibular nystagmus. The pause in firing began after saccade onset, was unrelated to saccade duration, and occurred even in complete darkness. 4. Most (90%) of the visual NOT units were direction selective. They exhibited an increase in firing above resting during horizontal (ipsilateral) background movement and/or during smooth pursuit of a moving spot and a decrease in firing during contralateral movement. 5. The firing rates of NOT units were highly dependent on stimulus velocity. All had velocity thresholds of less than 1 degree/s and exhibited a monotonic increase in firing rate with visual stimulus velocity over part (n = 90%) or all (n = 10%) of the tested range (i.e., 1–200 degrees/s). Most NOT units exhibited velocity tuning with an average preferred velocity of 64 degrees/s.(ABSTRACT TRUNCATED AT 400 WORDS)

Ocular Motor Disorders Caused by Lesions in the Brainstem

2008 ◽  
Author(s):  
Agnes Wong
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Head Tracking ◽  
Dorsomedial Nucleus ◽  
Abducens Nucleus ◽  
Burst Neurons ◽  
Gaze Holding ◽  
Clinical Correlate ◽  
Cerebellar Peduncle ◽  
Ventral Paraflocculus

Oculopalatal tremor usually occurs many months after an initial insult, due to neural deafferentation. It rarely resolves spontaneously. Treatment is with gabapentin, ceruletide, or anticolinergic agents. The y-group is a small group of cells that lies rostral to the inferior cerebellar peduncle. It receives inputs from the saccule (part of the otolith) and from Purkinje cells of the flocculus, and it projects to the oculomotor and trochlear nuclei via the superior cerebellar peduncle and a crossing ventral tegmental tract. 1. Discharge during upward smooth pursuit, optokinetic, and combined eye-head tracking (VOR cancellation), but not during VOR in darkness (see sections 3.14 and 5.2) 2. Together with the flocculus and ventral paraflocculus, may contribute to vertical VOR adaptation (see section 3.12) No known documented clinical correlate Collections of neurons scattered along the midline fiber tracts in the pons and medulla, including: 1. The nucleus pararaphales in the medulla, which receives vertical eye position signals from the INC, and projects to the flocculus and ventral paraflocculus 2. The nucleus incertus in the pons, which contains burst-tonic neurons that mainly discharge in relation to horizontal eye movements, and projects to the flocculus Function: may send an “efference copy” of eye movement commands to the flocculus for gaze holding or longer term adaptation No known documented clinical correlate The abducens nucleus contains: 1. Abducens motoneurons that innervate the ipsilateral lateral rectus 2. Abducens internuclear neurons, the axons of which cross the midline and ascend via the MLF to innervate the contralateral medial rectus motoneurons in the oculomotor nucleus. 3. Neurons that project to the cerebeller flocculus The abducens nucleus is the final common motor pathway for horizontal conjugate eye movements, as it receives input for horizontal saccades, VOR, and smooth pursuit. The paramedian pontine reticular formation (PPRF) contains: Excitatory burst neurons (EBN) in the dorsomedial nucleus reticularis pontis caudalis (NRPC) that ■ Project to the ipsilateral abducens nucleus to generate ipsilateral, conjugate, horizontal saccades ■ Project to inhibitory burst neurons in the nucleus paragigantocellularis dorsalis (PGD) and receive inhibitory inputs from omnipause neurons in nucleus raphe interpositus (rip)

Improved visual sensitivity during smooth pursuit eye movements: Temporal and spatial characteristics

2009 ◽  
Vol 26 (3) ◽  
pp. 329-340 ◽  
Author(s):  
ALEXANDER C. SCHÜTZ ◽  
DORIS I. BRAUN ◽  
KARL R. GEGENFURTNER
Keyword(s):  
Eye Movements ◽  
Contrast Sensitivity ◽  
Smooth Pursuit ◽  
Temporal Frequency ◽  
Consistent Difference ◽  
Smooth Pursuit Eye Movements ◽  
Pursuit Eye Movements ◽  
Spatial Frequencies ◽  
Wide Range ◽  
Temporal And Spatial

AbstractRecently, we showed that contrast sensitivity for color and high–spatial frequency luminance stimuli is enhanced during smooth pursuit eye movements (Schütz et al., 2008). In this study, we investigated the enhancement over a wide range of temporal and spatial frequencies. In Experiment 1, we measured the temporal impulse response function (TIRF) for colored stimuli. The TIRF for pursuit and fixation differed mostly with respect to the gain but not with respect to the natural temporal frequency. Hence, the sensitivity enhancement seems to be rather independent of the temporal frequency of the stimuli. In Experiment 2, we measured the spatial contrast sensitivity function for luminance-defined Gabor patches with spatial frequencies ranging from 0.2 to 7 cpd. We found a sensitivity improvement during pursuit for spatial frequencies above 2–3 cpd. Between 0.5 and 3 cpd, sensitivity was impaired by smooth pursuit eye movements, but no consistent difference was observed below 0.5 cpd. The results of both experiments are consistent with an increased contrast gain of the parvocellular retinogeniculate pathway.

scholarly journals Role of Primate Cerebellar Hemisphere in Voluntary Eye Movement Control Revealed by Lesion Effects

2009 ◽  
Vol 101 (2) ◽  
pp. 934-947 ◽  
Author(s):  
Masafumi Ohki ◽  
Hiromasa Kitazawa ◽  
Takahito Hiramatsu ◽  
Kimitake Kaga ◽  
Taiko Kitamura ◽  
...  
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Smooth Pursuit ◽  
Movement Control ◽  
Cerebellar Hemisphere ◽  
Target Velocity ◽  
Eye Movement Control ◽  
Pursuit Eye Movements ◽  
Catch Up

The anatomical connection between the frontal eye field and the cerebellar hemispheric lobule VII (H-VII) suggests a potential role of the hemisphere in voluntary eye movement control. To reveal the involvement of the hemisphere in smooth pursuit and saccade control, we made a unilateral lesion around H-VII and examined its effects in three Macaca fuscata that were trained to pursue visually a small target. To the step (3°)-ramp (5–20°/s) target motion, the monkeys usually showed an initial pursuit eye movement at a latency of 80–140 ms and a small catch-up saccade at 140–220 ms that was followed by a postsaccadic pursuit eye movement that roughly matched the ramp target velocity. After unilateral cerebellar hemispheric lesioning, the initial pursuit eye movements were impaired, and the velocities of the postsaccadic pursuit eye movements decreased. The onsets of 5° visually guided saccades to the stationary target were delayed, and their amplitudes showed a tendency of increased trial-to-trial variability but never became hypo- or hypermetric. Similar tendencies were observed in the onsets and amplitudes of catch-up saccades. The adaptation of open-loop smooth pursuit velocity, tested by a step increase in target velocity for a brief period, was impaired. These lesion effects were recognized in all directions, particularly in the ipsiversive direction. A recovery was observed at 4 wk postlesion for some of these lesion effects. These results suggest that the cerebellar hemispheric region around lobule VII is involved in the control of smooth pursuit and saccadic eye movements.

scholarly journals The Impact of Neonatal Morbidities on Smooth Pursuit Eye Movements in Very Preterm Infants

2011 ◽  
Vol 70 ◽  
pp. 352-352 ◽  
Author(s):  
K Strand Brodd ◽  
K Rosander ◽  
H Grönqvist ◽  
G Holmström ◽  
B Strömberg ◽  
...  
Keyword(s):  
Eye Movements ◽  
Preterm Infants ◽  
Smooth Pursuit ◽  
Smooth Pursuit Eye Movements ◽  
Very Preterm Infants ◽  
Very Preterm ◽  
Pursuit Eye Movements ◽  
The Impact

scholarly journals Directed Gaze Trajectories for Biometric Presentation Attack Detection

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1394
Author(s):  
Asad Ali ◽  
Sanaul Hoque ◽  
Farzin Deravi
Keyword(s):  
Eye Movements ◽  
Visual Stimuli ◽  
Attack Detection ◽  
Movement Data ◽  
Biometric Systems ◽  
Planar Geometries ◽  
Presentation Attack Detection

Presentation attack artefacts can be used to subvert the operation of biometric systems by being presented to the sensors of such systems. In this work, we propose the use of visual stimuli with randomised trajectories to stimulate eye movements for the detection of such spoofing attacks. The presentation of a moving visual challenge is used to ensure that some pupillary motion is stimulated and then captured with a camera. Various types of challenge trajectories are explored on different planar geometries representing prospective devices where the challenge could be presented to users. To evaluate the system, photo, 2D mask and 3D mask attack artefacts were used and pupillary movement data were captured from 80 volunteers performing genuine and spoofing attempts. The results support the potential of the proposed features for the detection of biometric presentation attacks.

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