Dependence on Target Configuration of Express Saccade-Related Activity in the Primate Superior Colliculus

1998 ◽  
Vol 80 (3) ◽  
pp. 1407-1426 ◽  
Author(s):  
Jay A. Edelman ◽  
Edward L. Keller
Keyword(s):  
Superior Colliculus ◽  
Target Selection ◽  
Visual Response ◽  
Express Saccades ◽  
Related Activity ◽  
Express Saccade ◽  
Spatial Properties ◽  
Target Configuration ◽  
Single Target ◽  
Single Burst

Edelman, Jay A. and Edward L. Keller. Dependence on target configuration of express saccade-related activity in the primate superior colliculus. J. Neurophysiol. 80: 1407–1426, 1998. To help understand how complex visual stimuli are processed into short-latency saccade motor programs, the activity of visuomotor neurons in the deeper layers of the superior colliculus was recorded while two monkeys made express saccades to one target and to two targets. It has been shown previously that the visual response and perimotor discharge characteristic of visuomotor neurons temporally coalesce into a single burst of discharge for express saccades. Here we seek to determine whether the distributed visual response to two targets spatially coalesces into a command appropriate for the resulting saccade. Two targets were presented at identical radial eccentricities separated in direction by 45°. A gap paradigm was used to elicit express saccades. Express saccades were more likely to land in between the two targets than were saccades of longer latency. The speeds of express saccades to two targets were similar to those of one target of similar vector, as were the trajectories of saccades to one and two targets. The movement fields for express saccades to two targets were more broad than those for saccades to one target for all neurons studied. For most neurons, the spatial pattern of discharge for saccades to two targets was better explained as a scaled version of the visual response to two spatially separate targets than as a scaled version of the perimotor response accompanying a saccade to a single target. Only the discharge of neurons with large movement fields could be equally well explained as a visual response to two targets or as a perimotor response for a one-target saccade. For most neurons, the spatial properties of discharge depended on the number of targets throughout the entire saccade-related burst. These results suggest that for express saccades to two targets the computation of saccade vector is not complete at the level of the superior colliculus for most neurons and an explicit process of target selection is not necessary at this level for the programming of an express saccade.

Dependence of Saccade-Related Activity in the Primate Superior Colliculus on Visual Target Presence

2001 ◽  
Vol 86 (2) ◽  
pp. 676-691 ◽  
Author(s):  
Jay A. Edelman ◽  
Michael E. Goldberg
Keyword(s):  
Superior Colliculus ◽  
Visual Target ◽  
Visual Response ◽  
Target Presence ◽  
Related Activity ◽  
Intermediate Layers ◽  
Saccade Velocity ◽  
Trial Basis ◽  
Visual Targets ◽  
Extracellular Activity

Neurons in the intermediate layers of the superior colliculus respond to visual targets and/or discharge immediately before and during saccades. These visual and motor responses have generally been considered independent, with the visual response dependent on the nature of the stimulus, and the saccade-related activity related to the attributes of the saccade, but not to how the saccade was elicited. In these experiments we asked whether saccade-related discharge in the superior colliculus depended on whether the saccade was directed to a visual target. We recorded extracellular activity of neurons in the intermediate layers of the superior colliculus of three rhesus monkeys during saccades in tasks in which we varied the presence or absence of a visual target and the temporal delays between the appearance and disappearance of a target and saccade initiation. Across our sample of neurons ( n = 64), discharge was highest when a saccade was made to a still-present visual target, regardless of whether the target had recently appeared or had been present for several hundred milliseconds. Discharge was intermediate when the target had recently disappeared and lowest when the target had never appeared during that trial. These results are consistent with the hypothesis that saccade-related discharge decreases as the time between the target disappearance and saccade initiation increases. Saccade velocity was also higher for saccades to visual targets, and correlated on a trial-by-trial basis with perisaccadic discharge for many neurons. However, discharge of many neurons was dependent on task but independent of saccade velocity, and across our sample of neurons, saccade velocity was higher for saccades made immediately after target appearance than would be predicted by discharge level. A tighter relationship was found between saccade precision and perisaccadic discharge. These findings suggest that just as the purpose of the saccadic system in primates is to drive the fovea to a visual target, presaccadic motor activity in the superior colliculus is most intense when such a target is actually present. This enhanced activity may, itself, contribute to the enhanced performance of the saccade system when the saccade is made to a real visual target.

Activity of visuomotor burst neurons in the superior colliculus accompanying express saccades

1996 ◽  
Vol 76 (2) ◽  
pp. 908-926 ◽  
Author(s):  
J. A. Edelman ◽  
E. L. Keller
Keyword(s):  
Superior Colliculus ◽  
Critical Role ◽  
Cell Activity ◽  
Saccade Latency ◽  
The Other ◽  
Target Onset ◽  
Express Saccades ◽  
Express Saccade ◽  
Burst Neurons ◽  
Saccade Onset

1. We recorded visuomotor burst neurons in the deeper layers of the superior colliculus while two monkeys (Macaca fascicularis) made short-latency saccades known as express saccades to visual targets in order to determine whether the visual discharge normally seen for these cells served as the premotor burst during express saccades. We then compared saccade-related activity during express saccades with that recorded during regular latency saccades and delayed saccades. 2. Saccade latency histograms for two monkeys during trials with a temporal gap between fixation-point offset and target onset showed a distinct peak of saccades around 70-80 ms. One monkey also showed an additional peak around 125 ms. 3. Express saccades were found on the average to have the same relationship of saccade peak velocity to saccade amplitude as regular latency saccades and delayed saccades. Express saccades tended to be somewhat more hypometric than the other classes of saccades. However, express saccades were clearly visually guided and not anticipatory responses. 4. For most cells studied (33/40), express saccades were accompanied by a single, uninterrupted burst of activity beginning 40-50 ms after target onset and continuing until sometime around the end of the saccade. For a smaller group of cells (7/40), two peaks of burst activity were seen, although the second peak was smaller and tended to occur late, after saccade onset. Across all cells, the peak of visuomotor cell activity during express saccades correlated just as well with target onset as it did with saccade onset. 5. When considered as discharge temporally aligned to the onset of the saccade, bursts accompanying express saccades tended to begin at approximately the same time as that for regular and delayed saccades. However, this discharge generally peaked earlier for express than for regular and delayed saccades. Also, the magnitude of discharge for express saccades was higher than that for delayed saccades throughout the burst. 6. When considered as discharge temporally aligned to the appearance of the target, bursts began earlier for express and regular saccade trials than for delayed saccade trials. Peak discharge tended to be greater for express saccades than for the other classes of saccades. 7. The results of this investigation are consistent with the suggestion that the visual burst of visuomotor neurons in the deeper layers of the superior colliculus plays a role in the initiation of express saccades similar to that played by the premotor burst for saccades of longer latency. The elevated discharge for express saccades supports the idea that the superior colliculus plays a more critical role in express saccade generation than in the generation of longer-latency saccades. The elevated discharge also suggests that visuomotor bursters do not code one-to-one for saccade velocity nor for saccade dynamic motor error.

scholarly journals Impairment but not abolishment of express saccades after unilateral or bilateral inactivation of the frontal eye fields

2020 ◽  
Vol 123 (5) ◽  
pp. 1907-1919 ◽  
Author(s):  
Suryadeep Dash ◽  
Tyler R. Peel ◽  
Stephen G. Lomber ◽  
Brian D. Corneil
Keyword(s):  
Superior Colliculus ◽  
Peak Velocity ◽  
Critical Role ◽  
Frontal Eye Fields ◽  
Express Saccades ◽  
Express Saccade ◽  
Cortical Cooling ◽  
Saccade Generation

Express saccades are the shortest-latency saccade. The frontal eye fields (FEF) are thought to promote express saccades by presetting the superior colliculus. Here, by reversibly inactivating the FEF either unilaterally or bilaterally via cortical cooling, we support this by showing that the FEF plays a facilitative but not critical role in express saccade generation. We also found that FEF inactivation lowered express saccade peak velocity, emphasizing a contribution of the FEF to express saccade kinematics.

scholarly journals Auditory signals evolve from hybrid- to eye-centered coordinates in the primate superior colliculus

2012 ◽  
Vol 108 (1) ◽  
pp. 227-242 ◽  
Author(s):  
Jungah Lee ◽  
Jennifer M. Groh
Keyword(s):  
Superior Colliculus ◽  
Reference Frame ◽  
Reference Frames ◽  
Visual Response ◽  
Response Patterns ◽  
Related Activity ◽  
Visual Spatial ◽  
Auditory Representation ◽  
Auditory Signals ◽  
Visual Targets

Visual and auditory spatial signals initially arise in different reference frames. It has been postulated that auditory signals are translated from a head-centered to an eye-centered frame of reference compatible with the visual spatial maps, but, to date, only various forms of hybrid reference frames for sound have been identified. Here, we show that the auditory representation of space in the superior colliculus involves a hybrid reference frame immediately after the sound onset but evolves to become predominantly eye centered, and more similar to the visual representation, by the time of a saccade to that sound. Specifically, during the first 500 ms after the sound onset, auditory response patterns ( N = 103) were usually neither head nor eye centered: 64% of neurons showed such a hybrid pattern, whereas 29% were more eye centered and 8% were more head centered. This differed from the pattern observed for visual targets ( N = 156): 86% were eye centered, <1% were head centered, and only 13% exhibited a hybrid of both reference frames. For auditory-evoked activity observed within 20 ms of the saccade ( N = 154), the proportion of eye-centered response patterns increased to 69%, whereas the hybrid and head-centered response patterns dropped to 30% and <1%, respectively. This pattern approached, although did not quite reach, that observed for saccade-related activity for visual targets: 89% were eye centered, 11% were hybrid, and <1% were head centered ( N = 162). The plainly eye-centered visual response patterns and predominantly eye-centered auditory motor response patterns lie in marked contrast to our previous study of the intraparietal cortex, where both visual and auditory sensory and motor-related activity used a predominantly hybrid reference frame ( Mullette-Gillman et al. 2005 , 2009 ). Our present findings indicate that auditory signals are ultimately translated into a reference frame roughly similar to that used for vision, but suggest that such signals might emerge only in motor areas responsible for directing gaze to visual and auditory stimuli.

scholarly journals Express saccades and superior colliculus responses are sensitive to short-wavelength cone contrast

2016 ◽  
Vol 113 (24) ◽  
pp. 6743-6748 ◽  
Author(s):  
Nathan J. Hall ◽  
Carol L. Colby
Keyword(s):  
Eye Movements ◽  
Superior Colliculus ◽  
Short Wavelength ◽  
Human Subjects ◽  
Reaction Times ◽  
Saccadic Eye Movements ◽  
Express Saccades ◽  
Color Information ◽  
Express Saccade ◽  
Psychophysical Studies

A key structure for directing saccadic eye movements is the superior colliculus (SC). The visual pathways that project to the SC have been reported to carry only luminance information and not color information. Short-wavelength–sensitive cones (S-cones) in the retina make little or no contribution to luminance signals, leading to the conclusion that S-cone stimuli should be invisible to SC neurons. The premise that S-cone stimuli are invisible to the SC has been used in numerous clinical and human psychophysical studies. The assumption that the SC cannot use S-cone stimuli to guide behavior has never been tested. We show here that express saccades, which depend on the SC, can be driven by S-cone input. Further, express saccade reaction times and changes in SC activity depend on the amount of S-cone contrast. These results demonstrate that the SC can use S-cone stimuli to guide behavior. We conclude that the use of S-cone stimuli is insufficient to isolate SC function in psychophysical and clinical studies of human subjects.

Extraretinal Inputs to Neurons in the Rostral Superior Colliculus of the Monkey During Smooth-Pursuit Eye Movements

2001 ◽  
Vol 86 (5) ◽  
pp. 2629-2633 ◽  
Author(s):  
Richard J. Krauzlis
Keyword(s):  
Eye Movements ◽  
Superior Colliculus ◽  
Smooth Pursuit ◽  
Saccadic Eye Movements ◽  
Visual Response ◽  
Smooth Pursuit Eye Movements ◽  
Related Activity ◽  
Pursuit Eye Movements ◽  
Deep Layers ◽  
Almost All

The intermediate and deep layers of the monkey superior colliculus (SC) are known to be important for the generation of saccadic eye movements. Recent studies have also provided evidence that the rostral SC might be involved in the control of pursuit eye movements. However, because rostral SC neurons respond to visual stimuli used to guide pursuit, it is also possible that the pursuit-related activity is simply a visual response. To test this possibility, we recorded the activity of neurons in the rostral SC as monkeys smoothly pursued a target that was briefly extinguished. We found that almost all rostral SC neurons in our sample maintained their pursuit-related activity during a brief visual blink, which was similar to the maintained activity they also exhibited during blinks imposed during fixation. These results indicate that discharge of rostral SC neurons during pursuit is not simply a visual response, but includes extraretinal signals.

scholarly journals Linking express saccade occurance to stimulus properties and sensorimotor integration in the superior colliculus

2015 ◽  
Vol 114 (2) ◽  
pp. 879-892 ◽  
Author(s):  
Robert A. Marino ◽  
Ron Levy ◽  
Douglas P. Munoz
Keyword(s):  
Action Potentials ◽  
Sensorimotor Integration ◽  
Arrival Time ◽  
Visual Response ◽  
Express Saccades ◽  
Visual Responses ◽  
Neural Signals ◽  
Express Saccade ◽  
Target Luminance ◽  
Sensory Motor

Express saccades represent the fastest possible eye movements to visual targets with reaction times that approach minimum sensory-motor conduction delays. Previous work in monkeys has identified two specific neural signals in the superior colliculus (SC: a midbrain sensorimotor integration structure involved in gaze control) that are required to execute express saccades: 1) previsual activity consisting of a low-frequency increase in action potentials in sensory-motor neurons immediately before the arrival of a visual response; and 2) a transient visual-sensory response consisting of a high-frequency burst of action potentials in visually responsive neurons resulting from the appearance of a visual target stimulus. To better understand how these two neural signals interact to produce express saccades, we manipulated the arrival time and magnitude of visual responses in the SC by altering target luminance and we examined the corresponding influences on SC activity and express saccade generation. We recorded from saccade neurons with visual-, motor-, and previsual-related activity in the SC of monkeys performing the gap saccade task while target luminance was systematically varied between 0.001 and 42.5 cd/m2 against a black background (∼0.0001 cd/m2). Our results demonstrated that 1) express saccade latencies were linked directly to the arrival time in the SC of visual responses produced by abruptly appearing visual stimuli; 2) express saccades were generated toward both dim and bright targets whenever sufficient previsual activity was present; and 3) target luminance altered the likelihood of producing an express saccade. When an express saccade was generated, visuomotor neurons increased their activity immediately before the arrival of the visual response in the SC and saccade initiation. Furthermore, the visual and motor responses of visuomotor neurons merged into a single burst of action potentials, while the visual response of visual-only neurons was unaffected. A linear combination model was used to test which SC signals best predicted the likelihood of producing an express saccade. In addition to visual response magnitude and previsual activity of saccade neurons, the model identified presaccadic activity (activity occurring during the 30-ms epoch immediately before saccade initiation) as a third important signal for predicting express saccades. We conclude that express saccades can be predicted by visual, previsual, and presaccadic signals recorded from visuomotor neurons in the intermediate layers of the SC.

scholarly journals Symbolic Cue-Driven Activity in Superior Colliculus Neurons in a Peripheral Visual Choice Task

2006 ◽  
Vol 95 (6) ◽  
pp. 3585-3595 ◽  
Author(s):  
Kyoung-Min Lee ◽  
Edward L. Keller
Keyword(s):  
Superior Colliculus ◽  
Target Selection ◽  
Saccadic Eye Movements ◽  
Spatial Location ◽  
Choice Response ◽  
Visual Response ◽  
Superior Colliculus Neurons ◽  
Response Task ◽  
And Control

Recent evidence implicates the superior colliculus (SC) in cognitive processes, such as target selection and control of spatial attention, in addition to the execution of saccadic eye movements. We report here the presence of a cognitive response in some cells in the SC in a task that requires the long-term association of spatial location with an arbitrary color. In this study, using a visual choice response task, we demonstrate that visuomotor neurons in the SC were activated by the appearance of a central symbolic cue delivered outside of the visual response fields of the recorded neurons. This procedure ensures that cognitively generated activity in these SC cells is not confounded with modulation of activity from previous visual stimuli that appeared in the response field of the neurons. The experiments suggest that cognitive signals can activate SC cells by themselves instead of only being able to modulate activities already evoked by visual events. Furthermore, a substantial fraction of these cells accurately reflected cue-aligned target selection in advance of saccade initiation. Our results add further support to other studies that have demonstrated that internally generated signals exist in SC cells.

Sign in / Sign up

Export Citation Format

Share Document