The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Isao Hayashi - One of the best experts on this subject based on the ideXlab platform.
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estimation of brain activity for perception of Aperture Problem
SCIS & ISIS SCIS & ISIS 2008, 2008Co-Authors: Isao Hayashi, Hisashi Toyoshima, Takahiro YamanoiAbstract:Aperture Problem is a psychological experiment for analyzing binding mechanism of the spatial recognition in an early stage of visual pathway. In this paper, we measure perceptual rate in the Aperture experiments, and discuss the dependency between the perception and various parameters in the experiments. We also record Electroencephalograms(EEG) of subjects who are recognizing the perception. By the elec- troencephalograms(EEG) analysis, we measure reaction latency of visual evoked potential (VEP) and event related potential(ERP) related to visual pathway, and estimate the localized equivalent current dipole(ECD) in the visual pathway. I. INTRODUCTION Aperture Problem (1)-(7) is a psychological experiment to analyze binding mechanism of the spatial recognition. A circular Aperture that a base bar moves in the background first is displayed at a central coordinate position of a computer display. While the base bar moves to the top right corner orientation from the the lower left side as the starting point, two other circles that a flanking bar moves in the background appear at both ends of the center circle. The flanking bar, however, moves to the upper orientation from the lower side. If a subject perceived that the line joining the base bar and the flanking bar is straight, his/her recognition for orientation of the base bar's movement would be dragged with the flanking bar's movement. The subject would so perceive that the base bar's movement was changed the same upper vertical orientation as the flanking bar. We call the phenomenon "per- ception". How will we perceive influence from neighboring other Apertures and we depend on an experimental parameters for moving lines? Nishina et al. (2) have already discussed that the perception strongly depends on radius, distance between circles and time scale for displaying the flanking bar (shortly, the display time) by binding mechanism. In human early visual pathway, a binding mechanism performs an important function. In this paper, we affirms Nishina's results and discussed the dependence of the perceptual rate on the display time (5), (6). However, we have simultaneously noticed that the perception rate rather decreases at the display time later than 550ms. We discussed so the dependence of the perceptual rate on the display time by the visual measurement analysis, and in addition we here estimate the localized equivalent current dipole(ECD) in the visual pathway by the electroen- cephalograms(EEG) analysis (8). By two kinds of analyses, we can discuss which localization of the brain relates to the perception, and what mechanism causes the perception in the Aperture Problem. In the visual measurement analysis, the perceptual recognition rate is calculated with changing radius, distance between circles, display time, and speed of bar. We particularly discuss the influence of the speed of bar to the perceptual rate. Meanwhile, we argue that subjects tend to fail to recognize the perception on the long display time. We then discuss the dependence of the perceptual rate on the speed of bar by trend analysis. In EEG analysis (9)- (11), we measure the visual evoked potential(VEP) and event related potential(ERP) of the perception in order to estimate the localization of the brain activity area with changing radius, distance between circles, display time, and speed of bar. Then, we discuss the relationship between the latency of VEP and ERP by the perception and the localized equivalent current dipole(ECD) in the visual pathway. At the last, we presume which part of the brain relates to VEP and ERP for the perception, and what mechanism causes the perception.
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spatio temporal analysis of brain activities on Aperture Problem
SCIS & ISIS SCIS & ISIS 2008, 2008Co-Authors: Atsushi Moritaka, Isao Hayashi, Hisashi Toyoshima, Takahiro Yamanoi, Hidetoshi NonakaAbstract:The Aperture Problem is a motion perception through a small window involved ambiguity both in a speed and a direction of the motion. It has been analyzed in various experimental approaches with knowledge about the early motion process in visual pathways of the human brain. Some of the present authors had investigated correct answer rate of the moving orientation and analyzed brain activities with different experimental parameters, such as line speed, radius of the Apertures, and length of a line. The present authors recorded electroencephalograms (EEGs) from a subject and estimated their sources and latencies in the brain using the equivalent current dipole source localization (ECDL) method. We compared localized ECDs for two different line speeds (Type 1: 10msec/pixel and Type 2: 20msec/pixel). At the latency of the appearance of Aperture, ECDs were localized along the ventral pathway concern with the recognition of form. After appearance of the line, ECDs were localized along the dorsal pathway concern with the recognition of movement. In addition, after appearance of another Aperture, ECDs were localized to the middle frontal gyrus and the inferior frontal gyrus.
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Recognition of perception and the localization for Aperture Problem in visual pathway of brain
2007 IEEE International Conference on Systems Man and Cybernetics, 2007Co-Authors: Isao Hayashi, Hisashi Toyoshima, Takahiro YamanoiAbstract:The Aperture Problem is the one of the experiments to analyze binding mechanism of the space recognition with the human visual pathway. Nishina has already insisted that recognition of visual perception by the Aperture Problem depends in display time. In this paper, we discuss how other experimental parameters, e.g., radius, distance between circles, and speed of bar depend with recognition rate by measurement analysis of the perception. We simultaneously estimate the reaction latency of the perception by electroencephalograms (EEG) analysis, and we localize the brain activity area by equivalent current dipole (ECD). We then discuss the relationship between the reaction latency of the visual evoked potential (VEP), event related potential (ERP) and the localized equivalent current dipole (ECD) in the visual pathway. By these discussion, we concluded that perception would be localized with the prefrontal lobe.
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SMC - Recognition of perception and the localization for Aperture Problem in visual pathway of brain
2007 IEEE International Conference on Systems Man and Cybernetics, 2007Co-Authors: Isao Hayashi, Hisashi Toyoshima, Takahiro YamanoiAbstract:The Aperture Problem is the one of the experiments to analyze binding mechanism of the space recognition with the human visual pathway. Nishina has already insisted that recognition of visual perception by the Aperture Problem depends in display time. In this paper, we discuss how other experimental parameters, e.g., radius, distance between circles, and speed of bar depend with recognition rate by measurement analysis of the perception. We simultaneously estimate the reaction latency of the perception by electroencephalograms (EEG) analysis, and we localize the brain activity area by equivalent current dipole (ECD). We then discuss the relationship between the reaction latency of the visual evoked potential (VEP), event related potential (ERP) and the localized equivalent current dipole (ECD) in the visual pathway. By these discussion, we concluded that perception would be localized with the prefrontal lobe.
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an analysis of Aperture Problem using fuzzy rules acquired from tam network
IEEE International Conference on Fuzzy Systems, 2002Co-Authors: Isao Hayashi, James R WilliamsonAbstract:The Aperture Problem is a kind of significant experiments for discussing visual models. A circle Aperture has been displayed at a computer CRT and a line inside the circle is moving. Then, a subject perceives perceptual grouping changing orientation of the line. In this paper, we analysis Aperture experiment data using fuzzy rules acquired from TAM network (topographic attentive mapping network) based on a biologically-motivated neural network with folded feedback mechanism.
Ryad Benosman - One of the best experts on this subject based on the ideXlab platform.
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Real-time high speed motion prediction using fast Aperture-robust event-driven visual flow.
IEEE transactions on pattern analysis and machine intelligence, 2020Co-Authors: Himanshu Akolkar, Sio Hoi Ieng, Ryad BenosmanAbstract:Optical flow is a crucial component of the feature space for early visual processing of dynamic scenes especially in new applications such as self-driving vehicles, drones and autonomous robots. The dynamic vision sensors are well suited for such applications because of their asynchronous, sparse and temporally precise representation of the visual dynamics. Many algorithms proposed for computing visual flow for these sensors suffer from the Aperture Problem as the direction of the estimated flow is governed by the curvature of the object rather than the true motion direction. Some methods that do overcome this Problem by temporal windowing under-utilize the true precise temporal nature of the dynamic sensors. In this paper, we propose a novel multi-scale plane fitting based visual flow algorithm that is robust to the Aperture Problem and also computationally fast and efficient. Our algorithm performs well in many scenarios ranging from fixed camera recording simple geometric shapes to real world scenarios such as camera mounted on a moving car and can successfully perform event-by-event motion estimation of objects in the scene to allow for predictions of up to 500 ms i.e. equivalent to 10 to 25 frames with traditional cameras.
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See before you see: Real-time high speed motion prediction using fast Aperture-robust event-driven visual flow.
arXiv: Computer Vision and Pattern Recognition, 2018Co-Authors: Himanshu Akolkar, Sio Hoi Ieng, Ryad BenosmanAbstract:Optical flow is a crucial component of the feature space for early visual processing of dynamic scenes especially in new applications such as self-driving vehicles, drones and autonomous robots. The dynamic vision sensors are well suited for such applications because of their asynchronous, sparse and temporally precise representation of the visual dynamics. Many algorithms proposed for computing visual flow for these sensors suffer from the Aperture Problem as the direction of the estimated flow is governed by the curvature of the object rather than the true motion direction. Some methods that do overcome this Problem by temporal windowing under-utilize the true precise temporal nature of the dynamic sensors. In this paper, we propose a novel multi-scale plane fitting based visual flow algorithm that is robust to the Aperture Problem and also computationally fast and efficient. Our algorithm performs well in many scenarios ranging from fixed camera recording simple geometric shapes to real world scenarios such as camera mounted on a moving car and can successfully perform event-by-event motion estimation of objects in the scene to allow for predictions of upto 500 ms i.e. equivalent to 10 to 25 frames with traditional cameras.
Guillaume S. Masson - One of the best experts on this subject based on the ideXlab platform.
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Motion-based prediction is sufficient to solve the Aperture Problem
Neural computation, 2012Co-Authors: Laurent Perrinet, Guillaume S. MassonAbstract:In low-level sensory systems, it is still unclear how the noisy information collected locally by neurons may give rise to a coherent global percept. This is well demonstrated for the detection of motion in the Aperture Problem: as luminance of an elongated line is symmetrical along its axis, tangential velocity is ambiguous when measured locally. Here, we develop the hypothesis that motion-based predictive coding is sufficient to infer global motion. Our implementation is based on a context-dependent diffusion of a probabilistic representation of motion. We observe in simulations a progressive solution to the Aperture Problem similar to physio-logy and behavior. We demonstrate that this solution is the result of two underlying mechanisms. First, we demonstrate the formation of a tracking behavior favoring temporally coherent features independent of their texture. Second, we observe that incoherent features are explained away, while coherent information diffuses progressively to the global scale. Most previous models included ad hoc mechanisms such as end-stopped cells or a selection layer to track specific luminance-based features as necessary conditions to solve the Aperture Problem. Here, we have proved that motion-based predictive coding, as it is implemented in this functional model, is sufficient to solve the Aperture Problem. This solution may give insights into the role of prediction underlying a large class of sensory computations.
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Motion direction integration following the onset of multistable stimuli (I): dynamic shifts in both perception and eye movements depend on signal strength
2012Co-Authors: Andrew Meso, Pierre Kornprobst, James Rankin, Olivier Faugeras, Guillaume S. MassonAbstract:We used an obliquely oriented moving luminance grating within a square Aperture as a stimulus. We probed how the Aperture Problem (determining direction of a contour within an Aperture) is solved following onset. It is perceived to move in horizontally (H), diagonally (D) or vertically (V), shifting perception during extended presentation. The initial percept (D) leads to two competing "stable" solutions H and V from the orthogonal 2D cues around the edges. During brief stimulus presentations of 200-500ms, participants reported perceived direction (H, D or V) in a 3-alternative forced choice task while eye movements were recorded. As expected when solving the Aperture Problem, integration took time: reported direction is predominantly 1D (D) at 200ms, shifting to 2D (H/V) by 500ms. Eye direction traces converge to an average direction (H, D or V) that corresponds to participant decisions. The latency of this separation of averaged traces depends on input signal strength parameters like contrast. The relationship between input signal, distributions of perceived direction and forced choice decision thresholds are well described by a neural fields model in our companion abstract (II). The onset dynamics of multistable direction representation are demonstrated to be well studied by ocular following eye movements.
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Motion-based predictive coding is sufficient to solve the Aperture Problem
BMC Neuroscience, 2011Co-Authors: Mina A. Khoei, Laurent Perrinet, Guillaume S. MassonAbstract:It is still unclear how information collected locally by low-level sensory neurons may give rise to a coherent global percept. This is well demonstrated in the Aperture Problem both in visual or haptic senses. Experimental findings on its biological solution in area MT show that local motion measures are integrated to see the dynamical emergence of global motion information [1]. We develop a theory of spatio-temporal integration defined as implementing motion-based predictive coding. This takes the form of an anisotropic, context-dependent diffusion of local information [2]. Here, we test this functional model for the Aperture Problem in the visual and haptic low-level sensory areas. In our model, spatial and motion information is represented in a probabilistic framework. Information is pooled using a Markov chain formulation, merging current information and measurement likelihood thanks to a prior on motion transition. This prior is defined so that it is adapted to smooth trajectories such as are observed in natural environments.This dynamical system favors temporally coherent features. Differently to neural approximations [3], we use a particle filtering method to implement this functional model. This generalizes Kalman filtering approaches that were used previously by allowing to represent non-gaussian and multimodal distributions. We observe the emergence of mechanisms that reflect observations made at psychophysical and behavioral levels. First, the dynamical system shows the emergence of the solution to the Aperture Problem and show dependence to line’s length [4]. Then,when presented with an object with a regular translation, the dynamical system grabs itsmotion independently of its shape and exhibits motion extrapolation. This shows that prediction is sufficient for the dynamical build-up of information from a local to a global scale. More generally it may give insights in the role of spatio-temporal integration on neural dynamics in the emergence of properties that are accredited to low-level sensory computations.
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A simple mechanism to reproduce the neural solution of the Aperture Problem in monkey area MT
2008Co-Authors: Maria-jose Escobar, Guillaume S. Masson, Pierre KornprobstAbstract:We propose a simple mechanism to reproduce the neural solution of the Aperture Problem in monkey area MT. More precisely, our goal is to propose a model able to reproduce the dynamical change of the preferred direction (PD) of a MT cell depending on the motion information contained in the input stimulus. The PD of a MT cell measured through drifting gratings differs of the one measured using a barberpole, which is highly related with its aspect ratio. For a barberpole, the PD evolves from the perpendicular direction of the drifting grating to a PD shifted according to the aspect ratio of the barberpole. The mechanisms underlying this dynamic are unknown (lateral connections, surround suppression, feed-backs from higher layers). Here, we show that a simple mechanism such as surround-inhibition in V1 neurons can produce a significant shift in the PD of MT neurons as observed with barberpoles of different aspect ratios.
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A Simple Mechanism to Reproduce the Neural Solution of the Aperture Problem in Monkey Area MT [ RR-6579]
2008Co-Authors: Maria-jose Escobar, Guillaume S. Masson, Pierre KornprobstAbstract:We propose a simple mechanism to reproduce the neural solution of the Aperture Problem in monkey area MT. More precisely, our goal is to propose a model able to reproduce the dynamical change of the preferred direction (PD) of a MT cell depending on the motion information contained in the input stimulus. The PD of a MT cell measured through drifting gratings differs of the one measured using a barberpole, which is highly related with its aspect ratio. For a barberpole, the PD evolves from the perpendicular direction of the drifting grating to a PD shifted according to the aspect ratio of the barberpole. The mechanisms underlying this dynamic are unknown (lateral connections, surround suppression, feed-backs from higher layers). Here, we show that a simple mechanism such as surround-inhibition in V1 neurons can produce a significant shift in the PD of MT neurons as observed with barberpoles of different aspect ratios
Takahiro Yamanoi - One of the best experts on this subject based on the ideXlab platform.
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estimation of brain activity for perception of Aperture Problem
SCIS & ISIS SCIS & ISIS 2008, 2008Co-Authors: Isao Hayashi, Hisashi Toyoshima, Takahiro YamanoiAbstract:Aperture Problem is a psychological experiment for analyzing binding mechanism of the spatial recognition in an early stage of visual pathway. In this paper, we measure perceptual rate in the Aperture experiments, and discuss the dependency between the perception and various parameters in the experiments. We also record Electroencephalograms(EEG) of subjects who are recognizing the perception. By the elec- troencephalograms(EEG) analysis, we measure reaction latency of visual evoked potential (VEP) and event related potential(ERP) related to visual pathway, and estimate the localized equivalent current dipole(ECD) in the visual pathway. I. INTRODUCTION Aperture Problem (1)-(7) is a psychological experiment to analyze binding mechanism of the spatial recognition. A circular Aperture that a base bar moves in the background first is displayed at a central coordinate position of a computer display. While the base bar moves to the top right corner orientation from the the lower left side as the starting point, two other circles that a flanking bar moves in the background appear at both ends of the center circle. The flanking bar, however, moves to the upper orientation from the lower side. If a subject perceived that the line joining the base bar and the flanking bar is straight, his/her recognition for orientation of the base bar's movement would be dragged with the flanking bar's movement. The subject would so perceive that the base bar's movement was changed the same upper vertical orientation as the flanking bar. We call the phenomenon "per- ception". How will we perceive influence from neighboring other Apertures and we depend on an experimental parameters for moving lines? Nishina et al. (2) have already discussed that the perception strongly depends on radius, distance between circles and time scale for displaying the flanking bar (shortly, the display time) by binding mechanism. In human early visual pathway, a binding mechanism performs an important function. In this paper, we affirms Nishina's results and discussed the dependence of the perceptual rate on the display time (5), (6). However, we have simultaneously noticed that the perception rate rather decreases at the display time later than 550ms. We discussed so the dependence of the perceptual rate on the display time by the visual measurement analysis, and in addition we here estimate the localized equivalent current dipole(ECD) in the visual pathway by the electroen- cephalograms(EEG) analysis (8). By two kinds of analyses, we can discuss which localization of the brain relates to the perception, and what mechanism causes the perception in the Aperture Problem. In the visual measurement analysis, the perceptual recognition rate is calculated with changing radius, distance between circles, display time, and speed of bar. We particularly discuss the influence of the speed of bar to the perceptual rate. Meanwhile, we argue that subjects tend to fail to recognize the perception on the long display time. We then discuss the dependence of the perceptual rate on the speed of bar by trend analysis. In EEG analysis (9)- (11), we measure the visual evoked potential(VEP) and event related potential(ERP) of the perception in order to estimate the localization of the brain activity area with changing radius, distance between circles, display time, and speed of bar. Then, we discuss the relationship between the latency of VEP and ERP by the perception and the localized equivalent current dipole(ECD) in the visual pathway. At the last, we presume which part of the brain relates to VEP and ERP for the perception, and what mechanism causes the perception.
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spatio temporal analysis of brain activities on Aperture Problem
SCIS & ISIS SCIS & ISIS 2008, 2008Co-Authors: Atsushi Moritaka, Isao Hayashi, Hisashi Toyoshima, Takahiro Yamanoi, Hidetoshi NonakaAbstract:The Aperture Problem is a motion perception through a small window involved ambiguity both in a speed and a direction of the motion. It has been analyzed in various experimental approaches with knowledge about the early motion process in visual pathways of the human brain. Some of the present authors had investigated correct answer rate of the moving orientation and analyzed brain activities with different experimental parameters, such as line speed, radius of the Apertures, and length of a line. The present authors recorded electroencephalograms (EEGs) from a subject and estimated their sources and latencies in the brain using the equivalent current dipole source localization (ECDL) method. We compared localized ECDs for two different line speeds (Type 1: 10msec/pixel and Type 2: 20msec/pixel). At the latency of the appearance of Aperture, ECDs were localized along the ventral pathway concern with the recognition of form. After appearance of the line, ECDs were localized along the dorsal pathway concern with the recognition of movement. In addition, after appearance of another Aperture, ECDs were localized to the middle frontal gyrus and the inferior frontal gyrus.
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Recognition of perception and the localization for Aperture Problem in visual pathway of brain
2007 IEEE International Conference on Systems Man and Cybernetics, 2007Co-Authors: Isao Hayashi, Hisashi Toyoshima, Takahiro YamanoiAbstract:The Aperture Problem is the one of the experiments to analyze binding mechanism of the space recognition with the human visual pathway. Nishina has already insisted that recognition of visual perception by the Aperture Problem depends in display time. In this paper, we discuss how other experimental parameters, e.g., radius, distance between circles, and speed of bar depend with recognition rate by measurement analysis of the perception. We simultaneously estimate the reaction latency of the perception by electroencephalograms (EEG) analysis, and we localize the brain activity area by equivalent current dipole (ECD). We then discuss the relationship between the reaction latency of the visual evoked potential (VEP), event related potential (ERP) and the localized equivalent current dipole (ECD) in the visual pathway. By these discussion, we concluded that perception would be localized with the prefrontal lobe.
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SMC - Recognition of perception and the localization for Aperture Problem in visual pathway of brain
2007 IEEE International Conference on Systems Man and Cybernetics, 2007Co-Authors: Isao Hayashi, Hisashi Toyoshima, Takahiro YamanoiAbstract:The Aperture Problem is the one of the experiments to analyze binding mechanism of the space recognition with the human visual pathway. Nishina has already insisted that recognition of visual perception by the Aperture Problem depends in display time. In this paper, we discuss how other experimental parameters, e.g., radius, distance between circles, and speed of bar depend with recognition rate by measurement analysis of the perception. We simultaneously estimate the reaction latency of the perception by electroencephalograms (EEG) analysis, and we localize the brain activity area by equivalent current dipole (ECD). We then discuss the relationship between the reaction latency of the visual evoked potential (VEP), event related potential (ERP) and the localized equivalent current dipole (ECD) in the visual pathway. By these discussion, we concluded that perception would be localized with the prefrontal lobe.
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A Measure of Localization of Brain Activity for the Motion Aperture Problem Using Electroencephalograms
Developing and Applying Biologically-Inspired Vision Systems, 1Co-Authors: Isao Hayashi, Hisashi Toyoshima, Takahiro YamanoiAbstract:When viewed through a limited-sized Aperture, bars appear to move in a direction normal to their orientation. This motion Aperture Problem is an important rubric for analyzing the early stages of visual processing particularly with respect to the perceptual completion of motion sampled across two or more Apertures. In the present study, a circular Aperture was displayed in the center of the visual field. While the baseline bar moved within the Aperture, two additional circular Apertures appeared; within each Aperture, a “flanker bar” appeared to move. For upwards movement of the flanker lines, subjects perceived the flanker bar to be connected to the base bar, and all three parts to move upward. The authors investigated the motion perception of the moving bars by changing the line speeds, radii of the Apertures, and distances between the circular Apertures and then analyzed spatio-temporal brain activities by electroencephalograms (EEGs). Latencies in the brain were estimated by using equivalent current dipole source (ECD) localization for one subject. Soon after the flankers appear, ECDs, assumed to be generated by the recognition of the Aperture’s form, were localized along the ventral pathway. After the bars moved, the ECDs were localized along the dorsal pathway, presumably in response to motion of the bars. In addition, for the perception of grouped motion and not normal motion, ECDs were localized to the middle frontal gyrus and the inferior frontal gyrus.
Richard T. Born - One of the best experts on this subject based on the ideXlab platform.
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End-Stopping and the Aperture Problem: Two-Dimensional Motion Signals in Macaque V1
Neuron, 2003Co-Authors: Christopher C. Pack, Margaret S. Livingstone, Kevin R. Duffy, Richard T. BornAbstract:Our perception of fine visual detail relies on small receptive fields at early stages of visual processing. However, small receptive fields tend to confound the orientation and velocity of moving edges, leading to ambiguous or inaccurate motion measurements (the Aperture Problem). Thus, it is often assumed that neurons in primary visual cortex (V1) carry only ambiguous motion information. Here we show that a subpopulation of V1 neurons is capable of signaling motion direction in a manner that is independent of contour orientation. Specifically, end-stopped V1 neurons obtain accurate motion measurements by responding only to the endpoints of long contours, a strategy which renders them largely immune to the Aperture Problem. Furthermore, the time course of end-stopping is similar to the time course of motion integration by MT neurons. These results suggest that cortical neurons might represent object motion by responding selectively to two-dimensional discontinuities in the visual scene.
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temporal dynamics of a neural solution to the Aperture Problem in visual area mt of macaque brain
Nature, 2001Co-Authors: Christopher C. Pack, Richard T. BornAbstract:A critical step in the interpretation of the visual world is the integration of the various local motion signals generated by moving objects. This process is complicated by the fact that local velocity measurements can differ depending on contour orientation and spatial position. Specifically, any local motion detector can measure only the component of motion perpendicular to a contour that extends beyond its field of view1,2. This “Aperture Problem”3 is particularly relevant to direction-selective neurons early in the visual pathways, where small receptive fields permit only a limited view of a moving object. Here we show that neurons in the middle temporal visual area (known as MT or V5) of the macaque brain reveal a dynamic solution to the Aperture Problem. MT neurons initially respond primarily to the component of motion perpendicular to a contour's orientation, but over a period of approximately 60 ms the responses gradually shift to encode the true stimulus direction, regardless of orientation. We also report a behavioural correlate of these neural responses: the initial velocity of pursuit eye movements deviates in a direction perpendicular to local contour orientation, suggesting that the earliest neural responses influence the oculomotor response.