Effects of eye position on saccadic eye movements and on the neuronal responses to auditory and visual stimuli in cat superior colliculus

1995 ◽  
Vol 103 (2) ◽  
Author(s):  
CarolK. Peck ◽  
JohnA. Baro ◽  
StephanieM. Warder
Keyword(s):  
Eye Movements ◽  
Superior Colliculus ◽  
Visual Stimuli ◽  
Saccadic Eye Movements ◽  
Eye Position ◽  
Neuronal Responses ◽  
Cat Superior Colliculus

Amplitude and Direction of Saccadic Eye Movements Depend on the Synchronicity of Collicular Population Activity

2004 ◽  
Vol 92 (1) ◽  
pp. 424-432 ◽  
Author(s):  
Michael Brecht ◽  
Wolf Singer ◽  
Andreas K. Engel
Keyword(s):  
Eye Movements ◽  
Saccadic Eye Movements ◽  
Brain Structures ◽  
High Temporal Resolution ◽  
Temporal Relations ◽  
Neuronal Responses ◽  
Population Activity ◽  
Neuronal Processing ◽  
The Individual ◽  
Cat Superior Colliculus

Synchronization of neuronal discharges has been observed in numerous brain structures, but opinions diverge regarding its significance in neuronal processing. Here we investigate whether the motion vectors of saccadic eye movements evoked by electrical multisite stimulation of the cat superior colliculus (SC) are influenced by varying the degree of synchrony between the stimulus trains. With synchronous activation of SC sites, the vectors of the resulting saccades correspond approximately to the averages of the vectors of saccades evoked from each site alone. In contrast, when the pulses of trains applied to the different sites are temporally offset by as little as 5–10 ms, the vectors of the resulting saccades come close to the sum of the individual vectors. Thus saccade vectors depend not only on the site and amplitude of collicular activation but also on the precise temporal relations among the respective spike trains. These data indicate that networks within or downstream from the SC discriminate with high temporal resolution between synchronous and asynchronous population responses. This supports the hypothesis that information is encoded not only in the rate of neuronal responses but also in the precise temporal relations between discharges.

Use of interrupted saccade paradigm to study spatial and temporal dynamics of saccadic burst cells in superior colliculus in monkey

1994 ◽  
Vol 72 (6) ◽  
pp. 2754-2770 ◽  
Author(s):  
E. L. Keller ◽  
J. A. Edelman
Keyword(s):  
Eye Movements ◽  
Superior Colliculus ◽  
Temporal Dynamics ◽  
Saccadic Eye Movements ◽  
Eye Position ◽  
Visual Response ◽  
Intermediate Layers ◽  
Saccade Onset ◽  
Spatial And Temporal Dynamics ◽  
Motor Error

1. We recorded the spatial and temporal dynamics of saccade-related burst neurons (SRBNs) found in the intermediate layers of the superior colliculus (SC) in the alert, behaving monkey. These burst cells are normally the first neurons recorded during radially directed microelectrode penetrations of the SC after the electrode has left the more dorsally situated visual layers. They have spatially delimited movement fields whose centers describe the well-studied motor map of the SC. They have a rather sharp, saccade-locked burst of activity that peaks just before saccade onset and then declines steeply during the saccade. Many of these cells, when recorded during saccade trials, also have an early, transient visual response and an irregular prelude of presaccadic activity. 2. Because saccadic eye movements normally have very stereotyped durations and velocity trajectories that vary systematically with saccade size, it has been difficult in the past to establish quantitatively whether the activity of SRBNs temporally codes dynamic saccadic control signals, e.g., dynamic motor error or eye velocity, where dynamic motor error is defined as a signal proportional to the instantaneous difference between desired final eye position and the actual eye position during a saccade. It has also not been unequivocally established whether SRBNs participate in an organized spatial shift of ensemble activity in the intermediate layers of the SC during saccadic eye movements. 3. To address these issues, we studied the activity of SRBNs using an interrupted saccade paradigm. Saccades were interrupted with pulsatile electrical stimulation through a microelectrode implanted in the omnipauser region of the brain stem while recordings were made simultaneously from single SRBNs in the SC. 4. Shortly after the beginning of the stimulation (which was electronically triggered at saccade onset), the eyes decelerated rapidly and stopped completely. When the high-frequency (typically 300-400 pulses per second) stimulation was terminated (average duration 12 ms), the eye movement was reinitiated and a resumed saccade was made accurately to the location of the target. 5. When we recorded from SRBNs in the more caudal colliculus, which were active for large saccades, cell discharge was powerfully and rapidly suppressed by the stimulation (average latency = 3.8 ms). Activity in the same cells started again just before the onset of the resumed saccade and continued during this saccade even though it has a much smaller amplitude than would normally be associated with significant discharge for caudal SC cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Role of striate cortex and superior colliculus in visual guidance of saccadic eye movements in monkeys

1977 ◽  
Vol 40 (1) ◽  
pp. 74-94 ◽  
Author(s):  
C. W. Mohler ◽  
R. H. Wurtz
Keyword(s):  
Eye Movements ◽  
Visual Field ◽  
Superior Colliculus ◽  
Stimulus Intensity ◽  
Macaca Mulatta ◽  
Striate Cortex ◽  
Visual Stimuli ◽  
Saccadic Eye Movements ◽  
Visual Guidance

1. We studied the effect of lesions placed in striate cortex or superior colliculus on the detection of visual stimuli and the accuracy of saccadic eye movements. The monkeys (Macaca mulatta) first learned to respond to a 0.25 degrees spot of light flashed for 150-200 ms in one part of the visual field while they were fixating in order to determine if they could detect the light. The monkeys also learned in a different task to make a saccade to the spot of light when the fixation point went out, and the accuracy of the saccades was measured. 2. Following a unilateral partial ablation of the striate cortex in two monkeys they could not detect the spot of light in the resulting scotoma or saccade to it. The deficit was only relative; if we increased the brightness of the stimulus from the usual 11 cd/m2 to 1,700 cd/m2 against a background of 1 cd/m2 the monkeys were able to detect and to make a saccade to the spot of light. 3. Following about 1 mo of practice on the detection and saccade tasks, the monkeys recovered the ability to detect the spots of light and to make saccades to them without gross errors (saccades made beyond an area of +/-3 average standard deviations). Lowering the stimulus intensity reinstated both the detection and saccadic errors...

Sensorimotor integration in the primate superior colliculus. I. Motor convergence

1987 ◽  
Vol 57 (1) ◽  
pp. 22-34 ◽  
Author(s):  
M. F. Jay ◽  
D. L. Sparks
Keyword(s):  
Eye Movements ◽  
Superior Colliculus ◽  
Visual Stimuli ◽  
Saccadic Eye Movements ◽  
Visual Signals ◽  
M Cells ◽  
Efferent Pathway ◽  
Saccadic Velocity ◽  
Visual Targets ◽  
Sensory Responses

Orienting movements of the eyes and head are made to both auditory and visual stimuli even though in the primary sensory pathways the locations of auditory and visual stimuli are encoded in different coordinates. This study was designed to differentiate between two possible mechanisms for sensory-to-motor transformation. Auditory and visual signals could be translated into common coordinates in order to share a single motor pathway or they could maintain anatomically separate sensory and motor routes for the initiation and guidance of orienting eye movements. The primary purpose of the study was to determine whether neurons in the superior colliculus (SC) that discharge before saccades to visual targets also discharge before saccades directed toward auditory targets. If they do, this would indicate that auditory and visual signals, originally encoded in different coordinates, have been converted into a single coordinate system and are sharing a motor circuit. Trained monkeys made saccadic eye movements to auditory or visual targets while the activity of visual-motor (V-M) cells and saccade-related burst (SRB) cells was monitored. The pattern of spike activity observed during trials in which saccades were made to visual targets was compared with that observed when comparable saccades were made to auditory targets. For most (57 of 59) V-M cells, sensory responses were observed only on visual trials. Auditory stimuli originating from the same region of space did not activate these cells. Yet, of the 72 V-M and SRB cells studied, 79% showed motor bursts prior to saccades to either auditory or visual targets. This finding indicates that visual and auditory signals, originally encoded in retinal and head-centered coordinates, respectively, have undergone a transformation that allows them to share a common efferent pathway for the generation of saccadic eye movements. Saccades to auditory targets usually have lower velocities than saccades of the same amplitude and direction made to acquire visual targets. Since fewer collicular cells are active prior to saccades to auditory targets, one determinant of saccadic velocity may be the number of collicular neurons discharging before a particular saccade.

scholarly journals Reversible Inactivation of Monkey Superior Colliculus. I. Curvature of Saccadic Trajectory

1998 ◽  
Vol 79 (4) ◽  
pp. 2082-2096 ◽  
Author(s):  
Hiroshi Aizawa ◽  
Robert H. Wurtz
Keyword(s):  
Eye Movements ◽  
Visual Field ◽  
Superior Colliculus ◽  
Saccadic Eye Movements ◽  
Cell Types ◽  
Neuron Activity ◽  
Eye Position ◽  
Two Dimensional ◽  
Reversible Inactivation ◽  
Intermediate Layers

Aizawa, Hiroshi and Robert H. Wurtz. Reversible inactivation of monkey superior colliculus. I. Curvature of saccadic trajectory. J. Neurophysiol. 79: 2082–2096, 1998. The neurons in the intermediate layers of the monkey superior colliculus (SC) that discharge before saccadic eye movements can be divided into at least two types, burst and buildup neurons, and the differences in their characteristics are compatible with different functional contributions of the two cell types. It has been suggested that a spread of activity across the population of the buildup neurons during saccade generation may contribute to the control of saccadic eye movements. The influence of any such spread should be on both the horizontal and vertical components of the saccade because the map of the movement fields on the SC is a two-dimensional one; it should affect the trajectory of saccade. The present experiments used muscimol injections to inactivate areas within the SC to determine the functional contribution of such a spread of activity on the trajectory of the saccades. The analysis concentrated on saccades made to areas of the visual field that should be affected primarily by alteration of buildup neuron activity. Muscimol injections produced saccades with altered trajectories; they became consistently curved after the injection, and successive saccades to the same targets had similar curvatures. The curved saccades showed changes in their direction and speed at the very beginning of the saccade, and for those saccades that reached the target, the direction of the saccade was altered near the end to compensate for the initially incorrect direction. Postinjection saccades had lower peak speeds, longer durations, and longer latencies for initiation. The changes in saccadic trajectories resulting from muscimol injections, along with the previous observations on changes in speed of saccades with such injections, indicate that the SC is involved in influencing the eye position during the saccade as well as at the end of the saccade. The changes in trajectory when injections were made more rostral in the SC than the most active burst neurons also are consistent with a contribution of the buildup neurons to the control of the eye trajectory. The results do not, however, support the hypothesis that the buildup neurons in the SC act as a spatial integrator.

scholarly journals A test of spatial temporal decoding mechanisms in the superior colliculus

2012 ◽  
Vol 107 (9) ◽  
pp. 2442-2452 ◽  
Author(s):  
Husam A. Katnani ◽  
A. J. Van Opstal ◽  
Neeraj J. Gandhi
Keyword(s):  
Nervous System ◽  
Motor Control ◽  
Eye Movements ◽  
Superior Colliculus ◽  
Motor Behavior ◽  
Saccadic Eye Movements ◽  
Population Coding ◽  
Population Activity ◽  
Low Levels

Population coding is a ubiquitous principle in the nervous system for the proper control of motor behavior. A significant amount of research is dedicated to studying population activity in the superior colliculus (SC) to investigate the motor control of saccadic eye movements. Vector summation with saturation (VSS) has been proposed as a mechanism for how population activity in the SC can be decoded to generate saccades. Interestingly, the model produces different predictions when decoding two simultaneous populations at high vs. low levels of activity. We tested these predictions by generating two simultaneous populations in the SC with high or low levels of dual microstimulation. We also combined varying levels of stimulation with visually induced activity. We found that our results did not perfectly conform to the predictions of the VSS scheme and conclude that the simplest implementation of the model is incomplete. We propose that additional parameters to the model might account for the results of this investigation.

Motor intention activity in the macaque's lateral intraparietal area. I. Dissociation of motor plan from sensory memory

1996 ◽  
Vol 76 (3) ◽  
pp. 1439-1456 ◽  
Author(s):  
P. Mazzoni ◽  
R. M. Bracewell ◽  
S. Barash ◽  
R. A. Andersen
Keyword(s):  
Eye Movements ◽  
Visual Stimulus ◽  
Visual Stimuli ◽  
Saccadic Eye Movements ◽  
Stimulus Location ◽  
Sensory Memory ◽  
Lateral Intraparietal Area ◽  
Preferred Direction ◽  
Motor Plan ◽  
Stimulation Of

1. The lateral intraparietal area (area LIP) of the monkey's posterior parietal cortex (PPC) contains neurons that are active during saccadic eye movements. These neurons' activity includes visual and saccade-related components. These responses are spatially tuned and the location of a neuron's visual receptive field (RF) relative to the fovea generally overlaps its preferred saccade amplitude and direction (i.e., its motor field, MF). When a delay is imposed between the presentation of a visual stimulus and a saccade made to its location (memory saccade task), many LIP neurons maintain elevated activity during the delay (memory activity, M), which appears to encode the metrics of the next intended saccadic eye movements. Recent studies have alternatively suggested that LIP neurons encode the locations of visual stimuli regardless of where the animal intends to look. We examined whether the M activity of LIP neurons specifically encodes movement intention or the locations of recent visual stimuli, or a combination of both. In the accompanying study, we investigated whether the intended-movement activity reflects changes in motor plan. 2. We trained monkeys (Macaca mulatta) to memorize the locations of two visual stimuli and plan a sequence of two saccades, one to each remembered target, as we recorded the activity of single LIP neurons. Two targets were flashed briefly while the monkey maintained fixation; after a delay the fixation point was extinguished, and the monkey made two saccades in sequence to each target's remembered location, in the order in which the targets were presented. This "delayed double saccade" (DDS) paradigm allowed us to dissociate the location of visual stimulation from the direction of the planned saccade and thus distinguish neuronal activity related to the target's location from activity related to the saccade plan. By imposing a delay, we eliminated the confounding effect of any phasic responses coincident with the appearance of the stimulus and with the saccade. 3. We arranged the two visual stimuli so that in one set of conditions at least the first one was in the neuron's visual RF, and thus the first saccade was in the neuron's motor field (MF). M activity should be high in these conditions according to both the sensory memory and motor plan hypotheses. In another set of conditions, the second stimulus appeared in the RF but the first one was presented outside the RF, instructing the monkey to plan the first saccade away from the neuron's MF. If the M activity encodes the motor plan, it should be low in these conditions, reflecting the plan for the first saccade (away from the MF). If it is a sensory trace of the stimulus' location, it should be high, reflecting stimulation of the RF by the second target. 4. We tested 49 LIP neurons (in 3 hemispheres of 2 monkeys) with M activity on the DDS task. Of these, 38 (77%) had M activity related to the next intended saccade. They were active in the delay period, as expected, if the first saccade was in their preferred direction. They were less active or silent if the next saccade was not in their preferred direction, even when the second stimulus appeared in their RF. 5. The M activity of 8 (16%) of the remaining neurons specifically encoded the location of the most recent visual stimulus. Their firing rate during the delay reflected stimulation of the RF independently of the saccade being planned. The remaining 3 neurons had M activity that did not consistently encode either the next saccade or the stimulus' location. 6. We also recorded the activity of a subset of neurons (n = 38) in a condition in which no stimulus appeared in a neuron's RF, but the second saccade was in the neuron's MF. In this case the majority of neurons tested (23/38, 60%) became active in the period between the first and second saccade, even if neither stimulus had appeared in their RF. Moreover, this activity appeared only after the first saccade had started in all but two of

Monkey superior colliculus represents rapid eye movements in a two-dimensional motor map

1993 ◽  
Vol 69 (3) ◽  
pp. 965-979 ◽  
Author(s):  
K. Hepp ◽  
A. J. Van Opstal ◽  
D. Straumann ◽  
B. J. Hess ◽  
V. Henn
Keyword(s):  
Eye Movements ◽  
Superior Colliculus ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Eye Position ◽  
Two Dimensional ◽  
Vestibular Nystagmus ◽  
Rapid Eye Movements ◽  
Q Model

1. Although the eye has three rotational degrees of freedom, eye positions, during fixations, saccades, and smooth pursuit, with the head stationary and upright, are constrained to a plane by ListingR's law. We investigated whether Listing's law for rapid eye movements is implemented at the level of the deeper layers of the superior colliculus (SC). 2. In three alert rhesus monkeys we tested whether the saccadic motor map of the SC is two dimensional, representing oculocentric target vectors (the vector or V-model), or three dimensional, representing the coordinates of the rotation of the eye from initial to final position (the quaternion or Q-model). 3. Monkeys made spontaneous saccadic eye movements both in the light and in the dark. They were also rotated about various axes to evoke quick phases of vestibular nystagmus, which have three degrees of freedom. Eye positions were measured in three dimensions with the magnetic search coil technique. 4. While the monkey made spontaneous eye movements, we electrically stimulated the deeper layers of the SC and elicited saccades from a wide range of initial positions. According to the Q-model, the torsional component of eye position after stimulation should be uniquely related to saccade onset position. However, stimulation at 110 sites induced no eye torsion, in line with the prediction of the V-model. 5. Activity of saccade-related burst neurons in the deeper layers of the SC was analyzed during rapid eye movements in three dimensions. No systematic eye-position dependence of the movement fields, as predicted by the Q-model, could be detected for these cells. Instead, the data fitted closely the predictions made by the V-model. 6. In two monkeys, both SC were reversibly inactivated by symmetrical bilateral injections of muscimol. The frequency of spontaneous saccades in the light decreased dramatically. Although the remaining spontaneous saccades were slow, Listing's law was still obeyed, both during fixations and saccadic gaze shifts. In the dark, vestibularly elicited fast phases of nystagmus could still be generated in three dimensions. Although the fastest quick phases of horizontal and vertical nystagmus were slower by about a factor of 1.5, those of torsional quick phases were unaffected. 7. On the basis of the electrical stimulation data and the properties revealed by the movement field analysis, we conclude that the collicular motor map is two dimensional. The reversible inactivation results suggest that the SC is not the site where three-dimensional fast phases of vestibular nystagmus are generated.(ABSTRACT TRUNCATED AT 400 WORDS)

Neuronal Responses Related to Smooth Pursuit Eye Movements in the Periarcuate Cortical Area of Monkeys

1998 ◽  
Vol 80 (1) ◽  
pp. 28-47 ◽  
Author(s):  
Masaki Tanaka ◽  
Kikuro Fukushima
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Cortical Area ◽  
Eye Position ◽  
Smooth Pursuit Eye Movements ◽  
Neuronal Responses ◽  
Stationary Target ◽  
Pursuit Eye Movements ◽  
Preferred Direction ◽  
Eye Velocity

Tanaka, Masaki and Kikuro Fukushima. Neuronal responses related to smooth pursuit eye movements in the periarcuate cortical area of monkeys. J. Neurophysiol. 80: 28–47, 1998. To examine how the periarcuate area is involved in the control of smooth pursuit eye movements, we recorded 177 single neurons while monkeys pursued a moving target in the dark. The majority (52%, 92/177) of task-related neurons responded to pursuit but had little or no response to saccades. Histological reconstructions showed that these neurons were located mainly in the posterior bank of the arcuate sulcus near the sulcal spur. Twenty-seven percent (48/177) changed their activity at the onset of saccades. Of these, 36 (75%) showed presaccadic burst activity with strong preference for contraversive saccades. Eighteen (10%, 18/177) were classified as eye-position–related neurons, and 11% (19/177) were related to other aspects of the stimuli or response. Among the 92 neurons that responded to pursuit, 85 (92%) were strongly directional with uniformly distributed preferred directions. Further analyses were performed in these directionally sensitive pursuit-related neurons. For 59 neurons that showed distinct changes in activity around the initiation of pursuit, the median latency from target motion was 96 ms and that preceding pursuit was −12 ms, indicating that these neuron can influence the initiation of pursuit. We tested some neurons by briefly extinguishing the tracking target ( n = 39) or controlling its movement with the eye position signal ( n = 24). The distribution of the change in pursuit-related activity was similar to previous data for the dorsomedial part of the medial superior temporal neurons ( Newsome et al. 1988) , indicating that pursuit-related neurons in the periarcuate area also carry extraretinal signals. For 22 neurons, we examined the responses when the animals reversed pursuit direction to distinguish the effects of eye acceleration in the preferred direction from oppositely directed eye velocity. Almost all neurons discharged before eye velocity reached zero, however, only nine neurons discharged before the eyes were accelerated in the preferred direction. The delay in neuronal responses relative to the onset of eye acceleration in these trials might be caused by suppression from oppositely directed pursuit velocity. The results suggest that the periarcuate neurons do not participate in the earliest stage of eye acceleration during the change in pursuit direction, although most of them may participate in the early stages of pursuit initiation in the ordinary step-ramp pursuit trials. Some neurons changed their activity when the animals fixated a stationary target, and this activity could be distinguished easily from the strong pursuit-related responses. Our results suggest that the periarcuate pursuit area carries extraretinal signals and affects the premotor circuitry for smooth pursuit.

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