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 Impairment but not abolishment of express saccades after unilateral- or bilateral cryogenic FEF inactivation

2019 ◽  
Author(s):  
Suryadeep Dash ◽  
Tyler R. Peel ◽  
Stephen G. Lomber ◽  
Brian D. Corneil
Keyword(s):  
Superior Colliculus ◽  
Visual Information ◽  
Peak Velocity ◽  
Critical Role ◽  
Frontal Eye Fields ◽  
Visually Guided ◽  
Express Saccades ◽  
Cortical Input ◽  
Cortical Areas ◽  
Intermediate Layers

AbstractExpress saccades (ESs) are a manifestation of a visual grasp reflex triggered when visual information arrives in the intermediate layers of the superior colliculus (SCi), which in turn orchestrates the lower level brainstem saccade generator to evoke a saccade with a very short latency (∼100ms). A prominent theory regarding express saccades generation is that they are facilitated by preparatory signals, presumably from cortical areas, which prime the SCi prior to the arrival of visual information. Here, we test this theory by reversibly inactivating a key cortical input to the SCi, the frontal eye fields (FEF), while monkeys perform an oculomotor task that promotes ES generation. Across three tasks with a different combination of potential target locations and uni- or bilateral FEF inactivation, we found a spared ability for monkeys to generate ESs, despite decreases in ES frequency during FEF inactivation. This result is consistent with the FEF having a facilitatory but not critical role in ES generation, likely because other cortical areas compensate for the loss of preparatory input to the SCi. However, we did find decreases in the accuracy and peak velocity of ESs generated during FEF inactivation, which argues for an influence of the FEF on the saccadic burst generator even during ESs. Overall, our results shed further light on the role of the FEF in the shortest-latency visually-guided eye movements.New & NoteworthyExpress saccades (ESs) are the shortest-latency visually-guided saccade. The frontal eye fields (FEF) is thought to promote ES by establishing the necessary preconditions in the superior colliculus. Here, by reversibly inactivate the FEF either unilaterally or bilaterally, we support this view by showing that the FEF plays an assistive but not critical role in ES generation. We also found that FEF inactivation lowered ES peak velocity, emphasizing a contribution of the FEF to ES kinematics.

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.

An examination of the variables that affect express saccade generation

2004 ◽  
Vol 21 (2) ◽  
pp. 119-127 ◽  
Author(s):  
PETER H. SCHILLER ◽  
JOHANNES HAUSHOFER ◽  
GEOFFERY KENDALL
Keyword(s):  
Rhesus Monkeys ◽  
Target Onset ◽  
Express Saccades ◽  
Express Saccade ◽  
Saccadic System ◽  
Fixation Spot ◽  
Temporal Asynchrony ◽  
Saccade Generation ◽  
Gap Time

The frequency with which express saccades are generated under a variety of conditions in rhesus monkeys was examined. Increasing the gap time between fixation spot termination and target onset increased express saccade frequency but was progressively less effective in doing so as the number of target positions in the sample was increased. Express saccades were rarely produced when two targets were presented simultaneously and the choice of either of which was rewarded; a temporal asynchrony of only 17 ms between the targets reinstated express saccade generation. Express saccades continued to be generated when the vergence or pursuit systems was coactivated with the saccadic system.

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.

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.

Effects of cooling somatosensory cortex on response properties of tactile cells in the superior colliculus

1986 ◽  
Vol 55 (6) ◽  
pp. 1352-1368 ◽  
Author(s):  
H. R. Clemo ◽  
B. E. Stein
Keyword(s):  
Receptive Field ◽  
Superior Colliculus ◽  
Somatosensory Cortex ◽  
Critical Role ◽  
Receptive Fields ◽  
Field Size ◽  
Specific Cell ◽  
Anterior Ectosylvian Sulcus ◽  
Cortical Cooling ◽  
Cortical Regions

The corticotectal influences of somatosensory cortex were investigated by using reversible deactivation of cortex by cooling. More than half of the somatosensory superior colliculus (SC) cells studied exhibited a response depression (often not apparent qualitatively) or an elimination of responses to somatosensory stimuli during the period in which cortex was rendered inactive. Responses were restored to their initial levels by cortical rewarming. Hyperresponsiveness was never observed as a consequence of cortical cooling. Susceptibility to cooling-induced depression was not invariably linked to a specific cell type, location in the SC, or receptive-field size. Yet cells that had small receptive fields and were activated by hair displacement had the highest probability of being affected by this procedure. In some cells a contraction of the receptive field was induced by cortical cooling. This observation is consistent with previous experiments that showed that SC somatosensory receptive fields are constructed by the convergence of ascending and descending inputs and indicates that the responsiveness of specific receptive-field regions may depend on the functional integrity of cortex. Two cortical regions were found to produce cooling-induced effects in somatosensory SC cells: 1) SIV (and para-SIV), located in the anterior ectosylvian sulcus, and 2) the cortex within the rostral suprasylvian sulcus. These results indicate that somatosensory cortex, like visual cortex, plays a critical role in modulating the responses of SC cells. Apparently, the ability of both somatosensory and visual SC cells to code the presence of peripheral stimuli depends largely on the functional influences of their respective cortices. However, in contrast to previous observations on visual corticotectal influences, no specific receptive-field properties could be shown to be impressed on SC cells by somatosensory cortex.

scholarly journals Control of Reflexive Saccades following Hemispherectomy

2011 ◽  
Vol 23 (6) ◽  
pp. 1368-1378 ◽  
Author(s):  
Patricia A. Reuter-Lorenz ◽  
Troy M. Herter ◽  
Daniel Guitton
Keyword(s):  
Superior Colliculus ◽  
Inhibitory Control ◽  
Intractable Epilepsy ◽  
Short Latency ◽  
Gap Effect ◽  
Express Saccades ◽  
Antisaccade Task ◽  
Intact Side ◽  
Reflexive Saccades ◽  
Saccade Generation

Individuals who have undergone hemispherectomy for treatment of intractable epilepsy offer a rare and valuable opportunity to examine the ability of a single cortical hemisphere to control oculomotor performance. We used peripheral auditory events to trigger saccades, thereby circumventing dense postsurgical hemianopia. In an antisaccade task, patients generated numerous unintended short-latency saccades toward contralesional auditory events, indicating pronounced limitations in the ability of a single hemicortex to exert normal inhibitory control over ipsilateral (i.e., contralesional) reflexive saccade generation. Despite reflexive errors, patients retained an ability to generate correct antisaccades in both directions. The prosaccade task revealed numerous contralesional express saccades, a robust contralesional gap effect, but the absence of both effects for ipsilesional saccades. These results indicate limits to the saccadic control capabilities following hemispherectomy: A single hemicortex can mediate antisaccades in both directions, but plasticity does not extend fully to the bilateral inhibition of reflexive saccades. We posit that these effects are due to altered control dynamics that reduce the responsivity of the superior colliculus on the intact side and facilitate the release of an auditory-evoked ocular grasp reflex into the blind hemifield that the intact hemicortex has difficulty suppressing.

Nonequivalent visual, auditory, and somatic corticotectal influences in cat

1978 ◽  
Vol 41 (1) ◽  
pp. 55-64 ◽  
Author(s):  
B. E. Stein
Keyword(s):  
Visual Cortex ◽  
Auditory Cortex ◽  
Superior Colliculus ◽  
Functional Significance ◽  
Critical Role ◽  
Visual Responses ◽  
Visual Cells ◽  
Acoustic Stimuli ◽  
Cortical Cooling ◽  
Cat Superior Colliculus

1. The effects of cortical cooling on the responses of cells to visual, somatic, and acoustic stimuli were studied in the cat superior colliculus (SC). When the visual cortex was cooled, the responses of many visual cells of the SC were depressed or eliminated, but the activity of nonvisual cells remained unchanged. This response depression was found in visual cells located in both superficial and deep laminae and was most pronounced in neurons which were binocular and directionally selective. 2. Cooling somatic and/or auditory cortex had no effect on visual SC cells and, with few exceptions, did not alter the activity of somatic or acoustic cells either. 3. The specificity of visual cortex influences on visual responding in the SC was most apparent in multimodal cells. In trimodal cells, the simultaneous cooling of visual, somatic, and auditory cortex eliminated responses to visual stimuli, but did not affect responses to somatic or acoustic stimuli. Visual responses were returned to the precooling level in both unimodal and multimodal cells by cortical rewarming. 4. The present experiments indicate that despite the organizational parallels among visual, somatic, and acoustic cells of the cat SC, the influences they receive from cortex are non-equivalent. Cortical influences appear to play a more critical role in the responses of visual cells than in the responses of somatic and acoustic cells. These observations raise questions about the functional significance of nonvisual corticotectal systems.

scholarly journals Frontal eye field inactivation reduces saccade preparation in the superior colliculus, but does not alter how preparatory activity relates to saccade latency

2017 ◽  
Author(s):  
Suryadeep Dash ◽  
Tyler R. Peel ◽  
Stephen G. Lomber ◽  
Brian D. Corneil
Keyword(s):  
Superior Colliculus ◽  
Reaction Times ◽  
Population Level ◽  
Visual Signals ◽  
Frontal Eye Fields ◽  
Visually Guided ◽  
Express Saccade ◽  
Preparatory Activity ◽  
Saccadic Reaction Times ◽  
Saccade Preparation

AbstractA neural correlate for saccadic reaction times (SRTs) in the gap saccade task is the level of preparatory activity in the intermediate layers of the superior colliculus (iSC) just before visual target onset: greater levels of iSC preparatory activity precede shorter SRTs. The frontal eye fields (FEF) are one likely source of such iSC preparatory activity, since FEF preparatory activity is also inversely related to SRT. To better understand the FEF’s role in saccade preparation, and the way in which such preparation relates to SRT, in two male rhesus monkeys we examined iSC preparatory activity during unilateral reversible cryogenic inactivation of the FEF. FEF inactivation increased contralesional SRTs, and lowered ipsilesional iSC preparatory activity. FEF inactivation also reduced fixation-related activity in the rostral iSC. Importantly, the distributions of SRTs generated with or without FEF inactivation overlapped, enabling us to conduct a novel population-level analyses examining iSC preparatory activity just before generation of SRT-matched saccades. These analyses revealed no change during FEF inactivation in the relationship between iSC preparatory activity and SRT-matched saccades across a range of SRTs, even for the occasional express saccade. Thus, while our results emphasize that the FEF has an overall excitatory influence on preparatory activity in the iSC, the communication between the iSC and downstream oculomotor brainstem is unaltered for SRT-matched saccades, suggesting that the integration of preparatory and visual signals in the SC just before saccade initiation is largely independent of the FEF for saccades generated in this task.Significance statementHow does the brain decide when to move? Here, we investigate the role of two oculomotor structures, the superior colliculus (SC) and frontal eye fields (FEF), in dictating visually-guided saccadic reaction times (SRTs). In both structures, higher levels of preparatory activity precede shorter SRTs. Here, we show that FEF inactivation increases SRTs and decreases SC preparatory activity. Surprisingly, a population-level analysis of SC preparatory activity showed a negligible impact of FEF inactivation, providing one examines SRT-matched saccades. Thus, while the FEF is one source of preparatory input to the SC, it is not a critical source, and it is not involved in the integration of preparatory activity and visual signals that precedes saccade initiation in simple visually-guided saccade tasks.

scholarly journals Nonlinear visuoauditory integration in the mouse superior colliculus

2021 ◽  
Author(s):  
Shinya Ito ◽  
Yufei Si ◽  
Alan M. Litke ◽  
David A. Feldheim
Keyword(s):  
Superior Colliculus ◽  
Sensory Integration ◽  
Large Scale ◽  
Temporal Dynamics ◽  
Critical Role ◽  
Sensory Information ◽  
Population Level ◽  
Object Identification ◽  
Response Properties ◽  
The Individual

AbstractSensory information from different modalities is processed in parallel, and then integrated in associative brain areas to improve object identification and the interpretation of sensory experiences. The Superior Colliculus (SC) is a midbrain structure that plays a critical role in integrating visual, auditory, and somatosensory input to assess saliency and promote action. Although the response properties of the individual SC neurons to visuoauditory stimuli have been characterized, little is known about the spatial and temporal dynamics of the integration at the population level. Here we recorded the response properties of SC neurons to spatially restricted visual and auditory stimuli using large-scale electrophysiology. We then created a general, population-level model that explains the spatial, temporal, and intensity requirements of stimuli needed for sensory integration. We found that the mouse SC contains topographically organized visual and auditory neurons that exhibit nonlinear multisensory integration. We show that nonlinear integration depends on properties of auditory but not visual stimuli. We also find that a heuristically derived nonlinear modulation function reveals conditions required for sensory integration that are consistent with previously proposed models of sensory integration such as spatial matching and the principle of inverse effectiveness.

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