scholarly journals Comparison of Cortico-Cortical and Cortico-Collicular Signals for the Generation of Saccadic Eye Movements

2002 ◽  
Vol 87 (2) ◽  
pp. 845-858 ◽  
Author(s):  
Stefano Ferraina ◽  
Martin Paré ◽  
Robert H. Wurtz
Keyword(s):  
Cerebral Cortex ◽  
Eye Movements ◽  
Visual Processing ◽  
Full Range ◽  
Saccadic Eye Movements ◽  
Projection Neurons ◽  
Visual Response ◽  
Antidromic Activation ◽  
Cortical Areas ◽  
Saccade Task

Many neurons in the frontal eye field (FEF) and lateral intraparietal (LIP) areas of cerebral cortex are active during the visual-motor events preceding the initiation of saccadic eye movements: they respond to visual targets, increase their activity before saccades, and maintain their activity during intervening delay periods. Previous experiments have shown that the output neurons from both LIP and FEF convey the full range of these activities to the superior colliculus (SC) in the brain stem. These areas of cerebral cortex also have strong interconnections, but what signals they convey remains unknown. To determine what these cortico-cortical signals are, we identified the LIP neurons that project to FEF by antidromic activation, and we studied their activity during a delayed-saccade task. We then compared these cortico-cortical signals to those sent subcortically by also identifying the LIP neurons that project to the intermediate layers of the SC. Of 329 FEF projection neurons and 120 SC projection neurons, none were co-activated by both FEF and SC stimulation. FEF projection neurons were encountered more superficially in LIP than SC projection neurons, which is consistent with the anatomical projection of many cortical layer III neurons to other cortical areas and of layer V neurons to subcortical structures. The estimated conduction velocities of FEF projection neurons (16.7 m/s) were significantly slower that those of SC projection neurons (21.7 m/s), indicating that FEF projection neurons have smaller axons. We identified three main differences in the discharge properties of FEF and SC projection neurons: only 44% of the FEF projection neurons changed their activity during the delayed-saccade task compared with 69% of the SC projection neurons; only 17% of the task-related FEF projection neurons showed saccadic activity, whereas 42% of the SC projection neurons showed such increases; 78% of the FEF projection neurons had a visual response but no saccadic activity, whereas only 55% of the SC projection neurons had similar activity. The FEF and SC projection neurons had three similarities: both had visual, delay, and saccadic activity, both had stronger delay and saccadic activity with visually guided than with memory-guided saccades, and both had broadly tuned responses for disparity stimuli, suggesting that their visual receptive fields have a three-dimensional configuration. These observations indicate that the activity carried between parietal and frontal cortical areas conveys a spectrum of signals but that the preponderance of activity conveyed might be more closely related to earlier visual processing than to the later saccadic stages that are directed to the SC.

scholarly journals Eye movements shape visual learning

2020 ◽  
Vol 117 (14) ◽  
pp. 8203-8211 ◽  
Author(s):  
Pooya Laamerad ◽  
Daniel Guitton ◽  
Christopher C. Pack
Keyword(s):  
Eye Movements ◽  
Visual Processing ◽  
Visual Learning ◽  
Visual Space ◽  
Saccadic Eye Movements ◽  
Spatial Integration ◽  
Perceptual Stability ◽  
Extensive Training ◽  
Visual Tasks ◽  
Saccade Task

Most people easily learn to recognize new faces and places, and with more extensive practice they can become experts at visual tasks as complex as radiological diagnosis and action video games. Such perceptual plasticity has been thoroughly studied in the context of training paradigms that require constant fixation. In contrast, when observers learn under more natural conditions, they make frequent saccadic eye movements. Here we show that such eye movements can play an important role in visual learning. Observers performed a task in which they executed a saccade while discriminating the motion of a cued visual stimulus. Additional stimuli, presented simultaneously with the cued one, permitted an assessment of the perceptual integration of information across visual space. Consistent with previous results on perisaccadic remapping [M. Szinte, D. Jonikaitis, M. Rolfs, P. Cavanagh, H. Deubel,J. Neurophysiol.116, 1592–1602 (2016)], most observers preferentially integrated information from locations representing the presaccadic and postsaccadic retinal positions of the cue. With extensive training on the saccade task, these observers gradually acquired the ability to perform similar motion integration without making eye movements. Importantly, the newly acquired pattern of spatial integration was determined by the metrics of the saccades made during training. These results suggest that oculomotor influences on visual processing, long thought to subserve the function of perceptual stability, also play a role in visual plasticity.

scholarly journals The role of action intentionality and effector in the subjective expansion of temporal duration after saccadic eye movements

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
David Melcher ◽  
Devpriya Kumar ◽  
Narayanan Srinivasan
Keyword(s):  
Eye Movements ◽  
Visual Processing ◽  
Saccadic Eye Movements ◽  
Intentional Binding ◽  
Opposite Pattern ◽  
Motor Action ◽  
Saccade Onset ◽  
Backward Shift ◽  
The Moment

Abstract Visual perception is based on periods of stable fixation separated by saccadic eye movements. Although naive perception seems stable (in space) and continuous (in time), laboratory studies have demonstrated that events presented around the time of saccades are misperceived spatially and temporally. Saccadic chronostasis, the “stopped clock illusion”, represents one such temporal distortion in which the movement of the clock hand after the saccade is perceived as lasting longer than usual. Multiple explanations for chronostasis have been proposed including action-backdating, temporal binding of the action towards the moment of its effect (“intentional binding”) and post-saccadic temporal dilation. The current study aimed to resolve this debate by using different types of action (keypress vs saccade) and varying the intentionality of the action. We measured both perceived onset of the motor action and perceived onset of an auditory tone presented at different delays after the keypress/saccade. The results showed intentional binding for the keypress action, with perceived motor onset shifted forwards in time and the time of the tone shifted backwards. Saccades resulted in the opposite pattern, showing temporal expansion rather than compression, especially with cued saccades. The temporal illusion was modulated by intentionality of the movement. Our findings suggest that saccadic chronostasis is not solely dependent on a backward shift in perceived saccade onset, but instead reflects a temporal dilation. This percept of an effectively “longer” period at the beginning of a new fixation may reflect the pattern of suppressed, and then enhanced, visual processing around the time of saccades.

Global visual processing for saccadic eye movements

1982 ◽  
Vol 22 (8) ◽  
pp. 1033-1045 ◽  
Author(s):  
John M. Findlay
Keyword(s):  
Eye Movements ◽  
Visual Processing ◽  
Saccadic Eye Movements

scholarly journals Contrast sensitivity, V1 neural activity, and natural vision

2017 ◽  
Vol 117 (2) ◽  
pp. 492-508 ◽  
Author(s):  
James E. Niemeyer ◽  
Michael A. Paradiso
Keyword(s):  
Eye Movements ◽  
Contrast Sensitivity ◽  
Visual Processing ◽  
Brain Area ◽  
Saccadic Eye Movements ◽  
Visual Sensitivity ◽  
Natural Image ◽  
Spatial Frequencies ◽  
Natural Vision ◽  
Common Laboratory

Contrast sensitivity is fundamental to natural visual processing and an important tool for characterizing both visual function and clinical disorders. We simultaneously measured contrast sensitivity and neural contrast response functions and compared measurements in common laboratory conditions with naturalistic conditions. In typical experiments, a subject holds fixation and a stimulus is flashed on, whereas in natural vision, saccades bring stimuli into view. Motivated by our previous V1 findings, we tested the hypothesis that perceptual contrast sensitivity is lower in natural vision and that this effect is associated with corresponding changes in V1 activity. We found that contrast sensitivity and V1 activity are correlated and that the relationship is similar in laboratory and naturalistic paradigms. However, in the more natural situation, contrast sensitivity is reduced up to 25% compared with that in a standard fixation paradigm, particularly at lower spatial frequencies, and this effect correlates with significant reductions in V1 responses. Our data suggest that these reductions in natural vision result from fast adaptation on one fixation that lowers the response on a subsequent fixation. This is the first demonstration of rapid, natural-image adaptation that carries across saccades, a process that appears to constantly influence visual sensitivity in natural vision. NEW & NOTEWORTHY Visual sensitivity and activity in brain area V1 were studied in a paradigm that included saccadic eye movements and natural visual input. V1 responses and contrast sensitivity were significantly reduced compared with results in common laboratory paradigms. The parallel neural and perceptual effects of eye movements and stimulus complexity appear to be due to a form of rapid adaptation that carries across saccades.

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)

Functional properties of monkey caudate neurons. I. Activities related to saccadic eye movements

1989 ◽  
Vol 61 (4) ◽  
pp. 780-798 ◽  
Author(s):  
O. Hikosaka ◽  
M. Sakamoto ◽  
S. Usui
Keyword(s):  
Eye Movements ◽  
Caudate Nucleus ◽  
Environmental Changes ◽  
Low Frequency ◽  
Saccadic Eye Movements ◽  
Spontaneous Discharge ◽  
Lateral Part ◽  
Visually Guided ◽  
Saccade Task ◽  
Time Gap

1. We recorded single cell activities in the caudate nucleus of the monkeys trained to perform a series of visuomotor tasks. In the first part of this paper, we summarize the types and locations of neurons in the monkey caudate nucleus. In the second part, we report the characteristics of neurons related to saccadic eye movements. 2. Neurons were classified into two types in terms of spontaneous discharge pattern. A majority of the neurons (2,287/2,559, 89%) had very low-frequency discharges (mostly less than 1 Hz). The rest (n = 272) showed irregular-tonic discharges (3-8 Hz) with broad spikes. 3. Of 2,559 neurons tested, 867 showed spike activity related to some aspects of the tasks; 502 neurons showed discharges in response to environmental changes outside, not in relation to, the tasks. None of the neurons responsive in or outside the tasks belonged to the irregular-tonic type. 4. The task-related activities were classified as: Saccade-related, Visual, Auditory, Cognitive, Fixation-related, and Reward-related. The activities detected outside the tasks were classified into: Visual, Auditory, Movement-related, Reward-related, and Other. Few neurons had both task-related and task-unrelated activities. 5. The locations of recorded neurons were determined using a coordinate system based on the anterior and posterior commissures. Task-related neurons were clustered longitudinally in the central part of the caudate. Neurons responsive outside the tasks were more widely distributed; specifically, auditory neurons were in the medial part, whereas movement-related neurons were in the lateral part. The irregular-tonic neurons were dispersed all over the caudate. 6. The monkey was trained to fixate on a spot of light on the screen and, when the spot moved, to follow it by making a saccade. A visually guided saccade occurred when the spot moved to another location without a time gap (saccade task). A memory-guided saccade occurred when the spot first disappeared and after a time gap reappeared at a fixed location (saccade with gap task). By delivering a cue stimulus while the monkey was fixating, a memory-guided saccade was elicited to a randomly chosen location (delayed saccade task).(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Humanoid Eyes: Perspective & Challenges

2019 ◽  
Author(s):  
Ahmad Yousef
Keyword(s):  
Prefrontal Cortex ◽  
Eye Movements ◽  
Brain Imaging ◽  
Saccadic Eye Movements ◽  
Essential Elements ◽  
Human Vision ◽  
Human Eye ◽  
Cortical Areas ◽  
The Continuum

This proposal offers perspective and challenges aiming to optimize and socialize the humanoid eyes. The main purpose of this proposal is to bring the readers’ attention to the importance and the sophistication of the human eye and its four dynamics continuum, namely, the continuum that may include saccadic eye movements, pupil variations, blinks along with duchenne markers. We suggested that the robotics’ designers to work collaboratively with neuroscientists to mathematically estimate the aforementioned continuum, and therefore, humanoid eyes/cameras can be perfectly invented; invention that we try to register its essential elements in the present study. The aforementioned collaboration will be very beneficial for an additional purpose, namely, because human vision indeed activates very many cortical areas that extended to the prefrontal cortex; the collaboration may effectively flourish the eye trackers to be good replacements of the expensive brain imaging in certain circumstances.

Visual, presaccadic, and cognitive activation of single neurons in monkey lateral intraparietal area

1996 ◽  
Vol 76 (5) ◽  
pp. 2841-2852 ◽  
Author(s):  
C. L. Colby ◽  
J. R. Duhamel ◽  
M. E. Goldberg
Keyword(s):  
Eye Movements ◽  
Stimulus Onset ◽  
Cognitive Factors ◽  
Visual Response ◽  
Single Neurons ◽  
Visual Responses ◽  
Related Activity ◽  
Lateral Intraparietal Area ◽  
Fixation Task ◽  
Saccade Task

1. Posterior parietal cortex contains neurons that are visually responsive and active in relation to saccadic eye movements. We recorded from single neurons in a subregion of parietal cortex, the lateral intraparietal area (LIP), in alert rhesus monkeys. To characterize more completely the circumstances under which LIP neurons are responsive, we used five tasks designed to test the impact of sensory, motor, and cognitive factors. We obtained quantitative data in multiple tasks in 91 neurons. We measured neural activity during central fixation and in relation to stimulus onset and saccade onset. 2. LIP neurons have visual responses to the onset of a stationary stimulus in the receptive field. These visual responses occurred both in tasks that require a subsequent eye movement toward the stimulus and in tasks in which eye movements are not permitted, indicating that this activity is sensory rather than presaccadic. 3. Visual responses were enhanced when the monkey had to use information provided by the stimulus to guide its behavior. The amplitude of the sensory response to a given stimulus was increased in a task in which the monkey would subsequently make a saccade to the location signaled by the stimulus, as compared with the amplitude of the visual response in a simple fixation task. 4. The visual response was also enhanced when the monkey attended to the stimulus without looking at it. This result shows that enhancement does not reflect saccade preparation because the response is enhanced even when the monkey is not permitted to make a saccade. Instead, enhancement reflects the allocation of attention to the spatial locus of the receptive field. 5. Many LIP neurons had saccade-related activity in addition to their visual responses. The visual response for most neurons was stronger than the saccade-related activation. 6. Saccade-related activity was independent of visual activity. Similar presaccadic activity was observed in trials that included a recent visual stimulus (memory-guided saccade task) and in trials with no visual stimulus (learned saccade task). 7. We observed increases in activity during fixation in tasks in which the monkey could anticipate the onset of a behaviorally significant stimulus. LIP neurons usually showed low levels of background firing in the fixation task during the period before stimulus onset. This background activity was increased in the peripheral attention and memory-guided saccade tasks during the period when the monkey was waiting for a behaviorally relevant stimulus to appear. 8. The results from these several tasks indicate that LIP neurons are activated in a variety of circumstances and are not involved exclusively in sensory processing or motor planning. The modulation of sensory responses by attention and anticipation suggests that cognitive factors play a major role in parietal function.

Visuomotor properties of corticotectal cells in area 17 and posteromedial lateral suprasylvian (PMLS) cortex of the cat

2001 ◽  
Vol 18 (1) ◽  
pp. 77-91 ◽  
Author(s):  
THEODORE G. WEYAND ◽  
ADELE C. GAFKA
Keyword(s):  
Eye Movements ◽  
Oculomotor System ◽  
Oscillatory Activity ◽  
Visual Response ◽  
Area 17 ◽  
Stimulus Motion ◽  
Velocity Amplitude ◽  
Cortical Areas ◽  
Saccade Velocity ◽  
Visual Cortical

We studied the visuomotor activity of corticotectal (CT) cells in two visual cortical areas [area 17 and the posteromedial lateral suprasylvian cortex (PMLS)] of the cat. The cats were trained in simple oculomotor tasks, and head position was fixed. Most CT cells in both cortical areas gave a vigorous discharge to a small stimulus used to control gaze when it fell within the retinotopically defined visual field. However, the vigor of the visual response did not predict latency to initiate a saccade, saccade velocity, amplitude, or even if a saccade would be made, minimizing any potential role these cells might have in premotor or attentional processes. Most CT cells in both areas were selective for direction of stimulus motion, and cells in PMLS showed a direction preference favoring motion away from points of central gaze. CT cells did not discharge with eye movements in the dark. During eye movements in the light, many CT cells in area 17 increased their activity. In contrast, cells in PMLS, including CT cells, were generally unresponsive during saccades. Paradoxically, cells in PMLS responded vigorously to stimuli moving at saccadic velocities, indicating that the oculomotor system suppresses visual activity elicited by moving the retina across an illuminated scene. Nearly all CT cells showed oscillatory activity in the frequency range of 20–90 Hz, especially in response to visual stimuli. However, this activity was capricious; strong oscillations in one trial could disappear in the next despite identical stimulus conditions. Although the CT cells in both of these regions share many characteristics, the direction anisotropy and the suppression of activity during eye movements which characterize the neurons in PMLS suggests that these two areas have different roles in facilitating perceptual/motor processes at the level of the superior colliculus.

Role of the Basal Ganglia in the Control of Purposive Saccadic Eye Movements

2000 ◽  
Vol 80 (3) ◽  
pp. 953-978 ◽  
Author(s):  
Okihide Hikosaka ◽  
Yoriko Takikawa ◽  
Reiko Kawagoe
Keyword(s):  
Eye Movements ◽  
Basal Ganglia ◽  
Saccadic Eye Movements ◽  
Behavioral Adaptation ◽  
Inhibitory Input ◽  
Behavioral Context ◽  
Critical Determinant ◽  
Cortical Areas ◽  
Cortical Inputs

In addition to their well-known role in skeletal movements, the basal ganglia control saccadic eye movements (saccades) by means of their connection to the superior colliculus (SC). The SC receives convergent inputs from cerebral cortical areas and the basal ganglia. To make a saccade to an object purposefully, appropriate signals must be selected out of the cortical inputs, in which the basal ganglia play a crucial role. This is done by the sustained inhibitory input from the substantia nigra pars reticulata (SNr) to the SC. This inhibition can be removed by another inhibition from the caudate nucleus (CD) to the SNr, which results in a disinhibition of the SC. The basal ganglia have another mechanism, involving the external segment of the globus pallidus and the subthalamic nucleus, with which the SNr-SC inhibition can further be enhanced. The sensorimotor signals carried by the basal ganglia neurons are strongly modulated depending on the behavioral context, which reflects working memory, expectation, and attention. Expectation of reward is a critical determinant in that the saccade that has been rewarded is facilitated subsequently. The interaction between cortical and dopaminergic inputs to CD neurons may underlie the behavioral adaptation toward purposeful saccades.

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