scholarly journals Robotic Vision with the Conformal Camera: Modeling Perisaccadic Perception

2010 ◽  
Vol 2010 ◽  
pp. 1-16 ◽  
Author(s):  
Jacek Turski
Keyword(s):  
Fourier Transform ◽  
Visual Information ◽  
Euclidean Geometry ◽  
Human Subjects ◽  
Receptive Fields ◽  
Saccadic Eye Movements ◽  
Robotic Vision ◽  
Non Euclidean Geometry ◽  
Silicon Retina ◽  
High Acuity

Humans make about 3 saccades per second at the eyeball's speed of 700 deg/sec to reposition the high-acuity fovea on the targets of interest to build up understanding of a scene. The brain's visuosaccadic circuitry uses the oculomotor command of each impending saccade to shift receptive fields (RFs) to cortical locations before the eyes take them there, giving a continuous and stable view of the world. We have developed a model for image representation based on projective Fourier transform (PFT) intended for robotic vision, which may efficiently process visual information during the motion of a camera with silicon retina that resembles saccadic eye movements. Here, the related neuroscience background is presented, effectiveness of the conformal camera's non-Euclidean geometry in intermediate-level vision is discussed, and the algorithmic steps in modeling perisaccadic perception with PFT are proposed. Our modeling utilizes basic properties of PFT. First, PFT is computable by FFT in complex logarithmic coordinates that also approximate the retinotopy. Second, the shift of RFs in retinotopic (logarithmic) coordinates is modeled by the shift property of discrete Fourier transform. The perisaccadic mislocalization observed by human subjects in laboratory experiments is the consequence of the fact that RFs' shifts are in logarithmic coordinates.

scholarly journals Canonical retinotopic shifts under an inverse force field explain predictive remapping

2021 ◽  
Author(s):  
Ifedayo-EmmanuEL Adeyefa-Olasupo ◽  
Zixuan Xiao ◽  
Anirvan S. Nandy
Keyword(s):  
Force Field ◽  
Temporal Dynamics ◽  
Human Subjects ◽  
Receptive Fields ◽  
Saccadic Eye Movements ◽  
Saccade Target ◽  
Brain Areas ◽  
Predictive Remapping ◽  
Spatio Temporal ◽  
Inverse Force

ABSTRACTSaccadic eye-movements allow us to bring visual objects of interest to high-acuity central vision. Although saccades cause large displacements of retinal images, our percept of the visual world remains stable. Predictive remapping — the ability of cells in retinotopic brain areas to transiently exhibit spatio-temporal retinotopic shifts beyond the spatial extent of their classical receptive fields — has been proposed as a primary mechanism that mediates this seamless visual percept. Despite the well documented effects of predictive remapping, no study to date has been able to provide a mechanistic account of the neural computations and architecture that actively mediate this ubiquitous phenomenon. Borne out by the spatio-temporal dynamics of peri-saccadic sensitivity to probe stimuli in human subjects, we propose a novel neurobiologically inspired phenomenological model in which the underlying peri-saccadic attentional and oculomotor signals manifest as three temporally overlapping forces that act on retinotopic brain areas. These three forces – a compressive one toward the center of gaze, a convergent one toward the saccade target and a translational one parallel to the saccade trajectory – act in an inverse force field and specify the spatio-temporal window of predictive remapping of population receptive fields.

Modulation of Gaze-Evoked Blinks Depends Primarily on Extraretinal Factors

2005 ◽  
Vol 93 (1) ◽  
pp. 627-632 ◽  
Author(s):  
Shawn S. Williamson ◽  
Ari Z. Zivotofsky ◽  
Michele A. Basso
Keyword(s):  
Visual Stimulus ◽  
Visual Information ◽  
Human Subjects ◽  
Saccadic Eye Movements ◽  
Spatial Location ◽  
Visually Guided ◽  
Gaze Shift ◽  
The Gaze ◽  
Extraretinal Signal ◽  
Common Drive

Gaze-evoked blinks are contractions of the orbicularis oculi (OO)—the lid closing muscle—occurring during rapid movements of the head and eyes and result from a common drive to the gaze and blink motor systems. However, blinks occurring during shifts of gaze are often suppressed when the gaze shift is made to an important visual stimulus, suggesting that the visual system can modulate the occurrence of these blinks. In head-stabilized, human subjects, we tested the hypothesis that the presence of a visual stimulus was sufficient, but not necessary, to modulate OO EMG (OOemg) activity during saccadic eye movements. Rapid, reorienting movements of the eyes (saccades) were made to visual targets that remained illuminated (visually guided trials) or were briefly flashed (memory-guided trials) at different amplitudes along the horizontal meridian. We measured OOemg activity and found that the magnitude and probability of OOemg activity occurrence was reduced when a saccade was made to the memory of the spatial location as well as to the actual visual stimulus. The reduced OOemg activity occurred only when the location of the target was previously cued. OOemg activity occurred reliably with spontaneous saccades that were made to locations with no explicit visual stimulus, generally, back to the fixation location. Thus the modulation of gaze-evoked OOemg activity does not depend on the presence of visual information per se, but rather, results from an extraretinal signal.

scholarly journals Gain control of saccadic eye movements is probabilistic

2019 ◽  
Vol 116 (32) ◽  
pp. 16137-16142 ◽  
Author(s):  
Matteo Lisi ◽  
Joshua A. Solomon ◽  
Michael J. Morgan
Keyword(s):  
Eye Movements ◽  
Cost Function ◽  
Visual Information ◽  
Gain Control ◽  
Saccadic Eye Movements ◽  
Systematic Bias ◽  
Visual Axis ◽  
Additional Time ◽  
High Acuity ◽  
Bayesian Control

Saccades are rapid eye movements that orient the visual axis toward objects of interest to allow their processing by the central, high-acuity retina. Our ability to collect visual information efficiently relies on saccadic accuracy, which is limited by a combination of uncertainty in the location of the target and motor noise. It has been observed that saccades have a systematic tendency to fall short of their intended targets, and it has been suggested that this bias originates from a cost function that overly penalizes hypermetric errors. Here, we tested this hypothesis by systematically manipulating the positional uncertainty of saccadic targets. We found that increasing uncertainty produced not only a larger spread of the saccadic endpoints but also more hypometric errors and a systematic bias toward the average of target locations in a given block, revealing that prior knowledge was integrated into saccadic planning. Moreover, by examining how variability and bias covaried across conditions, we estimated the asymmetry of the cost function and found that it was related to individual differences in the additional time needed to program secondary saccades for correcting hypermetric errors, relative to hypometric ones. Taken together, these findings reveal that the saccadic system uses a probabilistic-Bayesian control strategy to compensate for uncertainty in a statistically principled way and to minimize the expected cost of saccadic errors.

Background Changes Delay Information Represented in Macaque V1 Neurons

2005 ◽  
Vol 94 (6) ◽  
pp. 4314-4330 ◽  
Author(s):  
Xin Huang ◽  
Michael A. Paradiso
Keyword(s):  
Visual Field ◽  
Visual Information ◽  
Time Course ◽  
Receptive Fields ◽  
Saccadic Eye Movements ◽  
Initial Response ◽  
Temporal Changes ◽  
Background Condition ◽  
V1 Neurons ◽  
Static Background

In natural behavioral situations, saccadic eye movements not only introduce new stimuli into V1 receptive fields, they also cause changes in the background. We recorded in awake macaque V1 using a fixation paradigm and compared evoked activity to small stimuli when the background was either static or changing as with a saccade. When a stimulus was shown on a static background, as in most previous experiments, the initial response was orientation selective and contrast was inversely correlated with response latency. When a stimulus was introduced with a background change, V1 neurons showed a qualitatively different temporal response pattern in which information about stimulus orientation and contrast was delayed. The delay in the representation of visual information was found with three different types of background change—luminance increment, luminance decrement, and a pattern change with fixed mean luminance. We also found that with a background change, V1 off responses were suppressed and had a shorter time course compared with the static-background situation. Our results suggest that the distribution of temporal changes across the visual field plays a fundamental role in determining V1 responses. In the static-background condition, temporal change in the visual input occurs only in a small portion of the visual field. In the changing-background condition, and presumably in natural vision, temporal changes are widely distributed. Thus a delayed representation of visual information may be more representative of natural visual situations.

Nonretinotopic visual processing in the brain

2015 ◽  
Vol 32 ◽  
Author(s):  
DAVID MELCHER ◽  
MARIA CONCETTA MORRONE
Keyword(s):  
Eye Movements ◽  
Visual Processing ◽  
Visual Information ◽  
Receptive Fields ◽  
Saccadic Eye Movements ◽  
Time Frame ◽  
Neural Firing ◽  
Temporal Properties ◽  
Behavioral Studies ◽  
Retinotopic Organization

AbstractA basic principle in visual neuroscience is the retinotopic organization of neural receptive fields. Here, we review behavioral, neurophysiological, and neuroimaging evidence for nonretinotopic processing of visual stimuli. A number of behavioral studies have shown perception depending on object or external-space coordinate systems, in addition to retinal coordinates. Both single-cell neurophysiology and neuroimaging have provided evidence for the modulation of neural firing by gaze position and processing of visual information based on craniotopic or spatiotopic coordinates. Transient remapping of the spatial and temporal properties of neurons contingent on saccadic eye movements has been demonstrated in visual cortex, as well as frontal and parietal areas involved in saliency/priority maps, and is a good candidate to mediate some of the spatial invariance demonstrated by perception. Recent studies suggest that spatiotopic selectivity depends on a low spatial resolution system of maps that operates over a longer time frame than retinotopic processing and is strongly modulated by high-level cognitive factors such as attention. The interaction of an initial and rapid retinotopic processing stage, tied to new fixations, and a longer lasting but less precise nonretinotopic level of visual representation could underlie the perception of both a detailed and a stable visual world across saccadic eye movements.

scholarly journals “I have Learned Non-Euclidean Geometry Just from this Book” - Some facets of the correspondence between Friedrich Engel and David Hilbert

2021 ◽  
Vol 76 (3) ◽  
Author(s):  
Peter Ullrich
Keyword(s):  
Present Article ◽  
19Th Century ◽  
Euclidean Geometry ◽  
Academic Life ◽  
David Hilbert ◽  
Non Euclidean Geometry ◽  
The 19Th Century

AbstractFriedrich Engel and David Hilbert learned to know each other at Leipzig in 1885 and exchanged letters in particular during the next 15 years which contain interesting information on the academic life of mathematicians at the end of the 19th century. In the present article we will mainly discuss a statement by Hilbert himself on Moritz Pasch’s influence on his views of geometry, and on personnel politics concerning Hermann Minkowski and Eduard Study but also Engel himself.

scholarly journals Langevin simulations of protoplasmic streaming in non-Euclidean geometry

2021 ◽  
Vol 1730 (1) ◽  
pp. 012037
Author(s):  
Shuta Noro ◽  
Masahiko Okumura ◽  
Satoshi Hongo ◽  
Shinichiro Nagahiro ◽  
Toshiyuki Ikai ◽  
...  
Keyword(s):  
Euclidean Geometry ◽  
Protoplasmic Streaming ◽  
Non Euclidean Geometry

Practical Non-Euclidean Geometry

1925 ◽  
Vol 12 (177) ◽  
pp. 422 ◽  
Author(s):  
T. C. J. Elliott
Keyword(s):  
Euclidean Geometry ◽  
Non Euclidean Geometry

Generalized signal-tuned Gabor approach for signal representation and analysis

2017 ◽  
Vol 28 (01) ◽  
pp. 1750001 ◽  
Author(s):  
José R. A. Torreão
Keyword(s):  
Fourier Transform ◽  
Visual Cortex ◽  
Fourier Transforms ◽  
Fractional Fourier Transform ◽  
Receptive Fields ◽  
Gabor Functions ◽  
Plausible Model ◽  
Spectral Signal ◽  
Potential Applications ◽  
Space Frequency

The signal-tuned Gabor approach is based on spatial or spectral Gabor functions whose parameters are determined, respectively, by the Fourier and inverse Fourier transforms of a given “tuning” signal. The sets of spatial and spectral signal-tuned functions, for all possible frequencies and positions, yield exact representations of the tuning signal. Moreover, such functions can be used as kernels for space-frequency transforms which are tuned to the specific features of their inputs, thus allowing analysis with high conjoint spatio-spectral resolution. Based on the signal-tuned Gabor functions and the associated transforms, a plausible model for the receptive fields and responses of cells in the primary visual cortex has been proposed. Here, we present a generalization of the signal-tuned Gabor approach which extends it to the representation and analysis of the tuning signal’s fractional Fourier transform of any order. This significantly broadens the scope and the potential applications of the approach.

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