Discharges of neurons in the dorsal paraflocculus of monkeys during eye movements and visual stimulation

1986 ◽  
Vol 56 (4) ◽  
pp. 1129-1146 ◽  
Author(s):  
H. Noda ◽  
A. Mikami

Extracellular recordings were obtained from 319 input units and 304 Purkinje cells (P-cells) in the dorsal paraflocculus of alert monkeys trained to fixate a visual target. They changed discharge rates with either eye movement, eye position, or visual stimulus movement. Of the 319 input units, recorded in the granular layer or white matter, most were mossy fibers (MFs), but 90 (28%) showed characteristic cellular spikes. The latter units were probably granular cells (p-GC). Of the 319 input units, 163 (51%) showed bursts with saccades (burst units) and 62 (19%) showed a prelude on the average 124 ms prior to the onset of saccade (long-lead burst units). Sixty-five (20%) had tonic activity related to eye position and also showed bursts with saccades (burst-tonic units), and the remaining 29 (9%) showed only tonic activity (tonic units). MFs and p-GCs showed no significant differences in the proportion of each type of unit or in their response properties. The majority of burst units (63%) were pan directional, whereas all long-lead burst units had directional selectivity. The preferred directions of long-lead burst, burst tonic, and directionally selective burst units were found in all four quadrants. Position-related activity was found in 48% of the burst-tonic and tonic units to be linearly related to eye position and to show position threshold. The other units also had position thresholds but their activity was not monotonically related to fixation position. Six climbing fibers (CFs), 32 input units (including 13 p-GC), and 8 P-cells showed cyclic responses during sinusoidal movements of a visual pattern. One class of MF units (57%) responded only to the direction, whereas the others responded to both the direction and retinal-slip velocity. Both CF and P-cell units responded to sinusoidal retinal-slip velocity. Of 67 input units, 23 showed cyclic modulation in firing during sinusoidal eye movements in the horizontal plane. Nineteen were burst-tonic and four were tonic units. They also showed position sensitivity. The phase of the cyclic responses tended to lag behind the eye velocity during low-frequency trackings. Of 237 P-cells, 163 (68.8%) discharged with saccades (burst P-cells), 42 (17.7%) paused with saccades (pause P-cells), and 32 (13.5%) discharged with saccades in one direction and paused in the other (burst-pause P-cells). Position sensitivity was found in 38 P-cells; 12 were burst, 5 were pause, and 10 were burst-pause P-cells. Eleven did not respond with saccades.(ABSTRACT TRUNCATED AT 400 WORDS)

1991 ◽  
Vol 66 (2) ◽  
pp. 485-496 ◽  
Author(s):  
D. L. Robinson ◽  
J. W. McClurkin ◽  
C. Kertzman ◽  
S. E. Petersen

1. We recorded from single neurons in awake, trained rhesus monkeys in a lighted environment and compared responses to stimulus movement during periods of fixation with those to motion caused by saccadic or pursuit eye movements. Neurons in the inferior pulvinar (PI), lateral pulvinar (PL), and superior colliculus were tested. 2. Cells in PI and PL respond to stimulus movement over a wide range of speeds. Some of these cells do not respond to comparable stimulus motion, or discharge only weakly, when it is generated by saccadic or pursuit eye movements. Other neurons respond equivalently to both types of motion. Cells in the superficial layers of the superior colliculus have similar properties to those in PI and PL. 3. When tested in the dark to reduce visual stimulation from the background, cells in PI and PL still do not respond to motion generated by eye movements. Some of these cells have a suppression of activity after saccadic eye movements made in total darkness. These data suggest that an extraretinal signal suppresses responses to visual stimuli during eye movements. 4. The suppression of responses to stimuli during eye movements is not an absolute effect. Images brighter than 2.0 log units above background illumination evoke responses from cells in PI and PL. The suppression appears stronger in the superior colliculus than in PI and PL. 5. These experiments demonstrate that many cells in PI and PL have a suppression of their responses to stimuli that cross their receptive fields during eye movements. These cells are probably suppressed by an extraretinal signal. Comparable effects are present in the superficial layers of the superior colliculus. These properties in PI and PL may reflect the function of the ascending tectopulvinar system.


2012 ◽  
Vol 25 (0) ◽  
pp. 171-172
Author(s):  
Fumio Mizuno ◽  
Tomoaki Hayasaka ◽  
Takami Yamaguchi

Humans have the capability to flexibly adapt to visual stimulation, such as spatial inversion in which a person wears glasses that display images upside down for long periods of time (Ewert, 1930; Snyder and Pronko, 1952; Stratton, 1887). To investigate feasibility of extension of vision and the flexible adaptation of the human visual system with binocular rivalry, we developed a system that provides a human user with the artificial oculomotor ability to control their eyes independently for arbitrary directions, and we named the system Virtual Chameleon having to do with Chameleons (Mizuno et al., 2010, 2011). The successful users of the system were able to actively control visual axes by manipulating 3D sensors held by their both hands, to watch independent fields of view presented to the left and right eyes, and to look around as chameleons do. Although it was thought that those independent fields of view provided to the user were formed by eye movements control corresponding to pursuit movements on human, the system did not have control systems to perform saccadic movements and compensatory movements as numerous animals including human do. Fluctuations in dominance and suppression with binocular rivalry are irregular, but it is possible to bias these fluctuations by boosting the strength of one rival image over the other (Blake and Logothetis, 2002). It was assumed that visual stimuli induced by various eye movements affect predominance. Therefore, in this research, we focused on influenced of patterns of eye movements on visual perception with binocular rivalry, and implemented functions to produce saccadic movements in Virtual Chameleon.


1990 ◽  
Vol 5 (1) ◽  
pp. 29-41 ◽  
Author(s):  
M. Ariel

AbstractIn order to evaluate the normal eye movements of the turtle, Pseudemys scripta elegans, the positions of each eye were recorded simultaneously using two search-coil contact lenses. Optokinetic nystagmus (OKN) was strikingly unyoked in this animal such that one eye's slow-phase velocity was substantially independent of that of the other eye. On the other hand, the fast-phase motions of both eyes occurred more or less in synchrony.An eye's slow-phase gain is primarily dependent on the direction and velocity of the stimulus to that eye. Using monocular stimuli, the highest mean gain (0.54 ± 0.047; mean ± standard error of mean) occurred using temporal-to-nasal movement at 2.5 deg/s. The mean OKN gain for nasal-to-temporal movement was only 0.13 ± 0.015 at that velocity. Additionally, using the optimal monocular stimulus (temporal-to-nasal stimulation at 2.5 deg/s) only drove the occluded eye to move nasal-to-temporally at 0.085 deg/s, equivalent to a “gain” of only 0.034 ± 0.011.The binocular OKN gain during rotational stimuli was higher than monocular gain, especially during nasal-to-temporal movement at high velocities. Also the difference in slow-phase eye velocity between the two eyes was smaller during binocular rotational stimuli. In contrast, when each eye simultaneously viewed its temporal-to-nasal stimulus at an equal velocity, two behaviors were observed. Often, OKN alternated between an animal's left eye and right eye. Occasionally, both eyes moved at equal but opposite velocities.These behavioral data provide a quantitative baseline to interpret the properties of the retinal slip information in the turtle's accessory optic system. Those properties are similar to the behavior of the turtle in that both are tuned to direction and velocity independently for each eye (Rosenberg & Ariel, 1990).


1990 ◽  
Vol 64 (2) ◽  
pp. 413-422 ◽  
Author(s):  
J. M. Delgado-Garcia ◽  
C. Evinger ◽  
M. Escudero ◽  
R. Baker

1. The activity of both accessory abducens (Acc Abd) and abducens (Abd) motoneurons (Mns) was recorded in the alert cat during eye retraction and rotational eye movements. Cats were fitted with two scleral coils, one measured rotational eye movements directly and the other retraction by distinguishing the translational component. 2. Acc Abd and Abd Mns were identified following antidromic activation from electrical stimulation of the ipsilateral VIth nerve. 3. In response to corneal air puffs, bursts of spikes were produced in all (n = 30) Acc Abd Mns. The burst began 7.2 +/- 1.2 (SD) ms after onset of the air puff and 8.9 +/- 1.9 ms before eye retraction. 4. Acc Abd Mns were silent throughout all types of rotational eye movements, and tonic activity was not observed during intervals without air-puff stimulation. 5. In contrast, all (n = 50) identified Abd Mns exhibited a burst and/or pause in activity preceding and during horizontal saccades as well as a tonic activity proportional to eye position. 6. Only 10% of Abd Mns fired a weak burst of spikes in response to air-puff stimulation. 7. We conclude that Acc Abd Mns are exclusively involved in eye retraction in the cat and that only a few Abd Mns have an eye-retraction signal added to their eye position and velocity signals. Thus any rotational eye-movement response described in retractor bulbi muscle must result from innervation by Mns located in the Abd and/or the oculomotor nuclei. 8. The organization of the prenuclear circuitry and species variation are discussed in view of the nictiating membrane extension response measured in associative learning.


1976 ◽  
Vol 39 (4) ◽  
pp. 852-870 ◽  
Author(s):  
D. L. Robinson ◽  
R. H. Wurtz

1. In order to see whether cells in the superficial layers of the monkey superior colliculus can differentiate between real stimulus movement and self-induced stimulus movement we compared the discharge of these cells to stimulus movement in front of the stationary eye with stimulus movement generated by eye movements across a stationary stimulus. 2. Most of the cells recorded (65% of 231 cells) responded to stimulus velocities in front of the stationary eye as fast as those occurring during the peak velocity of a saccadic eye movement. Those cells that do respond usually have weak inhibitory regions and tend to have receptive fields further from fovea. 3. Move (61% of 105 cells) of the cells that did respond to rapid stimulus movement did not respond when an eye movement swept the receptive field over a stationary stimulus. 4. About half of these cells differentiated between these stimulus conditions when we used stimuli at least 1 log unit above background illumination; the remaining cells differentiated for stimuli 2 and 3 log units above background. Many cells differentiated between the two stimulus conditions over a wide range of directions of movement and the effect appears with about equal frequency in receptive fields at all distances from the fovea. 5. The differentiation is present for most cells even when the background illumination is reduced, indicating that visual factors are not the cause of the effect on these cells but may modify the response of other cells. 6. The suppression of background activity accompanying eye movements in the light is present following eye movements made in total darkness; the suppression, therefore, must result from an extraretinal signal. 4. The failure of these cells to respond to visual stimulation during eye movements is due to the same extraretinal signal that produces the suppression since a) the cells that show this suppression tend to be those that fail to respond to stimuli during eye movements, b) the time course of the suppression matches the time at which the effects of visual stimulation during an eye movement would reach the colliculus, and c) the cells which differentiate also show a decreased responsiveness to visual stimulation during the time of background suppression. While this extraretinal signal has the characteristics one would expect of a corollary discharge, proprioception as a source of the signal cannot be excluded. 8. Cells which differentiate between the two stimulus conditions usually also show an enhanced response to a visual stimulus in their receptive field when it is to be the target for a saccadic eye movement. These cells in the superior colliculus receive an extraretinal input which permits them to differentiate betweent real stimulus movements and stimulus movements resulting from the monkey's own eye movements. This differentiation would provide an uncontaminated visual movement signal and facilitate the detection of real movement in the environment...


1990 ◽  
Vol 63 (5) ◽  
pp. 1262-1275 ◽  
Author(s):  
L. S. Stone ◽  
S. G. Lisberger

1. We report the complex-spike responses of two groups of Purkinje cells (P-cells). The cell were classified according to their simple-spike firing during smooth eye movements evoked by visual and vestibular stimuli with the use of established criteria (Lisberger and Fuchs 1978; Stone and Lisberger 1990). During pursuit with the head fixed, ipsi gaze-velocity P-cells (GVP-cells) showed increased simple-spike firing when gaze moved toward the side of the recording, whereas down GVP-cells showed increased simple-spike firing when gaze moved downward. 2. During pursuit of sinusoidal target motion, the complex-spike firing rate was modulated out-of-phase with the simple-spike firing rate. Ipsi GVP-cells showed increased complex-spike firing during pursuit away from the side of the recording, and down GVP-cells showed increased complex-spike firing during upward pursuit. The strength of the complex-spike response increased as a function of the frequency of sinusoidal target motion. 3. GVP-cells showed directionally selective complex-spike responses during the initiation of pursuit to ramp target motion. Ipsi GVP-cells had increased complex-spike firing 100 ms after the onset of contralaterally directed target motion and decreased complex-spike activity after the onset of ipsilaterally directed target motion. Down GVP-cells had increased complex-spike firing 100 ms after the onset of upward target motion and decreased firing after the onset of downward target motion. As during sinusoidal target motion, each cell's simple- and complex-spike responses had the opposite directional preferences. 4. When the monkeys fixated a stationary target during a transient vestibular stimulus, the retinal slip caused by the 14-ms latency of the vestibuloocular reflex (VOR) affected the complex-spike firing rate. For ipsi GVP-cells, ipsilateral head motion caused transient contralateral image motion and an increase in complex-spike firing. The same vestibular stimulus in darkness caused an almost identical eye movement but had no effect on complex-spike firing. We conclude that complex spikes in ipsi GVP-cells are driven by contralaterally directed image motion. 5. To determine the events surrounding complex-spike firing during pursuit, we triggered averages of eye and target velocity on the occurrence of complex spikes during pursuit of sine-wave target motion. The averages revealed a transient pulse of retinal image motion that peaked approximately 100 ms before the complex spike. We conclude that complex spikes during steady-state pursuit are driven by the retinal slip associated with imperfect pursuit.(ABSTRACT TRUNCATED AT 400 WORDS)


1984 ◽  
Vol 52 (4) ◽  
pp. 743-761 ◽  
Author(s):  
L. E. Mays ◽  
J. D. Porter

Single<unit recordings were made from neurons with horizontal eye position sensitivity in the oculomotor and abducens nuclei in alert monkeys. The animals were trained to perform a visual tracking task that resulted in conjugate eye movements or symmetrical vergence movements. Scatterplots were obtained for unit firing rate as a function of the position of the ipsilateral eye for both types of movement. The slopes of the linear regression line were computed for conjugate (kc) and vergence movements (kv). Previous recording studies implied that kv should be equal to kc for most, if not all, abducens and oculomotor neurons. Other lines of evidence suggested that kv should be zero for a substantial proportion of abducens neurons. In the abducens nucleus, we found some cells for which kv matched kc, and a few cells with a kv value of zero. However, the majority of abducens units had vergence signals that were neither equal to zero nor to their conjugate signals. Overall, kv/kc was 0.62, and the correlation between kv and kc was not significantly different from zero. Similarly, in the oculomotor nucleus, kv was significantly different from kc for a majority of the cells. A few units had kv values less than or equal to zero, whereas other cells had very high kv values. Overall, the kv/kc for oculomotor units was nearly unity (0.94), and the correlation between kv and kc was 0.31. These results confirm previous reports that most neurons in the abducens and oculomotor nuclei with a horizontal eye position sensitivity carry both conjugate and vergence eye movement signals. We do not find that the relative magnitudes of these signals are closely matched for most neurons. It is more likely that vergence and conjugate signals are matched globally, for an entire nucleus, rather than for individual motoneurons. This view is consistent with the hypothesis that conjugate and vergence signals are generated independently and combined for the first time at the motoneurons. Our results also imply that some motoneurons play a more important role than others in either vergence or conjugate movements.


1984 ◽  
Vol 36 (1) ◽  
pp. 75-88 ◽  
Author(s):  
Hitoshi Honda

Pointing accuracy with an unseen hand to a just-extinguished visual target was examined in various eye movement conditions. When subjects caught the target by a saccade, they showed about the same degree of accuracy as that shown in pointing to a visible target. On the other hand, when subjects tracked a moving target by a pursuit eye movement, they systematically undershot when subsequently pointing to the target. The differential effect of the two types of eye movements on pointing tasks was examined on both the preferred and non-preferred hands, and it was found that the effect of eye movements was more prominent on the preferred hand than on the non-preferred hand. The results are discussed in relation to outflow eye position information.


1971 ◽  
Vol 54 (2) ◽  
pp. 403-414
Author(s):  
J. R. JOHNSTONE ◽  
R. F. MARK

1. Neurones which fire at the same time as saccades are found in the tectal commissure of carp. They are unaffected by visual stimuli or by paralysis of eye muscles and so their activity is not directly related to sensory input. 2. Twenty-two units have been examined. They fire in bursts only during eye movements and only for a particular direction of movement, either eyes-left or eyes-right. They begin to fire a few milliseconds before eye movement begins, slowly at first, reach a maximum frequency of about 300 Hz, then slow again and stop after about 100 ms. 3. In two instances such units have been recorded simultaneously in paralysed fish with a tonically firing unit, presumably visual, which was suppressed during each burst. In one case the tonic activity after each burst was increased, in the other it was decreased. 4. We suggest they are efference copy neurones, responsible for perceptual stability during eye movements. Their possible function is discussed in detail. They are not tectal motoneurones because the same eye movements continue after total removal of the tectum. Neither are they dependent on sensory input resulting from eye movement because their discharge patterns are unaffected by darkness or paralysis.


2000 ◽  
Vol 84 (2) ◽  
pp. 1035-1049 ◽  
Author(s):  
E. Aksay ◽  
R. Baker ◽  
H. S. Seung ◽  
D. W. Tank

Previous work in goldfish has suggested that the oculomotor velocity-to-position neural integrator for horizontal eye movements may be confined bilaterally to a distinct group of medullary neurons that show an eye-position signal. To establish this localization, the anatomy and discharge properties of these position neurons were characterized with single-cell Neurobiotin labeling and extracellular recording in awake goldfish while monitoring eye movements with the scleral search-coil method. All labeled somata ( n = 9) were identified within a region of a medially located column of the inferior reticular formation that was ∼350 μm in length, ∼250 μm in depth, and ∼125 μm in width. The dendrites of position neurons arborized over a wide extent of the ventral half of the medulla with especially heavy ramification in the initial 500 μm rostral of cell somata ( n = 9). The axons either followed a well-defined ventral pathway toward the ipsilateral abducens ( n = 4) or crossed the midline ( n = 2) and projected toward the contralateral group of position neurons and the contralateral abducens. A mapping of the somatic region using extracellular single unit recording revealed that position neurons ( n > 120) were the dominant eye-movement-related cell type in this area. Position neurons did not discharge below a threshold value of horizontal fixation position of the ipsilateral eye. Above this threshold, firing rates increased linearly with increasing temporal position [mean position sensitivity = 2.8 (spikes/s)/°, n = 44]. For a given fixation position, average rates of firing were higher after a temporal saccade than a nasal one ( n = 19/19); the magnitude of this hysteresis increased with increasing position sensitivity. Transitions in firing rate accompanying temporal saccades were overshooting ( n = 43/44), beginning, on average, 17.2 ms before saccade onset ( n = 17). Peak firing rate change accompanying temporal saccades was correlated with eye velocity ( n = 36/41). The anatomical findings demonstrate that goldfish medullary position neurons have somata that are isolated from other parts of the oculomotor system, have dendritic fields overlapping with axonal terminations of neurons with velocity signals, and have axons that are capable of relaying commands to the abducens. The physiological findings demonstrate that the signals carried by position neurons could be used by motoneurons to set the fixation position of the eye. These results are consistent with a role for position neurons as elements of the velocity-to-position neural integrator for horizontal eye movements.


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