scholarly journals Visual space-time interactions: Effects of adapting to spatial frequencies on temporal sensitivity

1990 ◽  
Vol 48 (5) ◽  
pp. 488-496 ◽  
Author(s):  
Marisa Carrasco
Keyword(s):  
Visual Space ◽  
Space Time ◽  
Spatial Frequencies

Visual space-time geometry - A tool for perception and the imagination

2002 ◽  
Vol 90 (7) ◽  
pp. 1113-1135 ◽  
Author(s):  
C. Fermuller ◽  
P. Baker ◽  
Y. Aloimonos
Keyword(s):  
Visual Space ◽  
Space Time

scholarly journals The Concept of space-time quanta in future technologies

2020 ◽  
Author(s):  
Igor Maydykovskiy ◽  
◽  
Petra Užpelkis ◽  
Keyword(s):  
Space Time ◽  
Natural Structure ◽  
Interference Structure ◽  
True Nature ◽  
Longitudinal Waves ◽  
Spatial Frequencies ◽  
Physical Essence ◽  
New Interpretation ◽  
Future Technologies ◽  
Asymmetric Interference

The article discusses the possibility of using the technological advantages that appear in connection with the discovery of the physical essence of Time and new interpretation of the structure of space in the form of space-time quanta. One of the problems that can be successfully solved on the basis of the new physical model is the problem of establishing the true nature of gravity. The solution to this problem is directly related to the implementation of the idea of unsupported motion based on the interaction in a certain way of the created asymmetric interference structure of longitudinal waves with the natural structure of spatial frequencies.

A Computational Structure for Generalized Visual Space-Time Chromatic Processing

2007 ◽  
pp. 90-95
Author(s):  
D. Freire-Obregón ◽  
R. Moreno-Díaz ◽  
R. Moreno-Díaz ◽  
G. De Blasio ◽  
A. Moreno-Díaz
Keyword(s):  
Visual Space ◽  
Space Time ◽  
Computational Structure ◽  
Chromatic Processing

Spatiotemporal organization of simple-cell receptive fields in the cat's striate cortex. I. General characteristics and postnatal development

1993 ◽  
Vol 69 (4) ◽  
pp. 1091-1117 ◽  
Author(s):  
G. C. DeAngelis ◽  
I. Ohzawa ◽  
R. D. Freeman
Keyword(s):  
Receptive Field ◽  
Postnatal Development ◽  
Striate Cortex ◽  
Receptive Fields ◽  
Space Time ◽  
Field Structure ◽  
Temporal Response ◽  
Spatial Frequencies ◽  
Spatiotemporal Receptive Field ◽  
Time Courses

1. Most studies of cortical neurons have focused on the spatial structure of receptive fields. For a more complete functional description of these neurons, it is necessary to consider receptive-field structure in the joint domain of space and time. We have studied the spatiotemporal receptive-field structure of 233 simple cells recorded from the striate cortex of adult cats and kittens at 4 and 8 wk postnatal. The dual goal of this study is to provide a detailed quantitative description of spatiotemporal receptive-field structure and to compare the developmental time courses of spatial and temporal response properties. 2. Spatiotemporal receptive-field profiles have been measured with the use of a reverse correlation method, in which we compute the cross-correlation between a neuron's response and a random sequence of small, briefly presented bright and dark stimuli. The receptive-field profiles of some simple cells are space-time separable, meaning that spatial and temporal response characteristics can be dissociated. Other cells have receptive-field profiles that are space-time inseparable. In these cases, a particular spatial location cannot be designated, unambiguously, as belonging to either an on or off subregion. However, separate on and off subregions may be clearly distinguished in the joint space-time domain. These subregions are generally tilted along an oblique axis. 3. Our observations show that spatial and temporal aspects of receptive-field structure mature with clearly different time courses. By 4 wk postnatal, the spatial symmetry and periodicity of simple-cell receptive fields have reached maturity. The spatial extent (or size) of these receptive fields is adult-like by 8 wk postnatal. In contrast, the response latency and time duration of spatiotemporal receptive fields do not mature until well beyond 8 wk postnatal. 4. By applying Fourier analysis to spatiotemporal receptive-field profiles, we have examined the postnatal development of spatial and temporal selectivity in the frequency domain. By 8 wk postnatal, spatial frequency tuning has clearly reached maturity. On the contrary, temporal frequency selectivity remains markedly immature at 8 wk. We have also examined the joint distribution of optimal spatial and temporal frequencies. From 4 wk postnatal until 8 wk postnatal, the range of optimal spatial frequencies increases substantially, whereas the range of optimal temporal frequencies remains largely unchanged. From 8 wk postnatal until adulthood, there is a large increase in optimal temporal frequencies for cells tuned to low spatial frequencies. For cells tuned to high spatial frequencies, the distribution of optimal temporal frequencies does not change much beyond 8 wk postnatal.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals The Concept of space-time quanta in future technologies

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Igor Maydykovskiy ◽  
◽  
Petras Užpelkis ◽  
Keyword(s):  
Space Time ◽  
Natural Structure ◽  
Interference Structure ◽  
True Nature ◽  
Longitudinal Waves ◽  
Spatial Frequencies ◽  
Physical Essence ◽  
New Interpretation ◽  
Future Technologies ◽  
Asymmetric Interference

The article discusses the possibility of using the technological advantages that appear in connection with the discovery of the physical essence of Time and new interpretation of the structure of space in the form of space-time quanta. One of the problems that can be successfully solved on the basis of the new physical model is the problem of establishing the true nature of gravity. The solution to this problem is directly related to the implementation of the idea of unsupported motion based on the interaction in a certain way of the created asymmetric interference structure of longitudinal waves with the natural structure of spatial frequencies.

Visual space is not cognitively impenetrable

1999 ◽  
Vol 22 (3) ◽  
pp. 366-367
Author(s):  
Yiannis Aloimonos ◽  
Cornelia Fermüller
Keyword(s):  
Visual Perception ◽  
Vision System ◽  
Visual Space ◽  
Space Time ◽  
Computational Vision ◽  
Objective Reality ◽  
Curved Space ◽  
The World

Cognitive impenetrability (CI) of a large part of visual perception is taken for granted by those of us in the field of computational vision who attempt to recover descriptions of space using geometry and statistics as tools. These tools clearly point out, however, that CI cannot extend to the level of structured descriptions of object surfaces, as Pylyshyn suggests. The reason is that visual space – the description of the world inside our heads – is a nonEuclidean curved space. As a consequence, the only alternative for a vision system is to develop several descriptions of space–time; these are representations of reduced intricacy and capture partial aspects of objective reality. As such, they make sense in the context of a class of tasks/actions/plans/purposes, and thus cannot be cognitively impenetrable.

scholarly journals Selective gating of retinal information by arousal

2020 ◽  
Author(s):  
Liang Liang ◽  
Alex Fratzl ◽  
Omar El Mansour ◽  
Jasmine D.S. Reggiani ◽  
Chinfei Chen ◽  
...  
Keyword(s):  
Visual Processing ◽  
Visual Information ◽  
Visual Stimuli ◽  
Sensory Information ◽  
Visual Space ◽  
Wide Field ◽  
Visual Responses ◽  
Visual Thalamus ◽  
Spatial Frequencies ◽  
Retinal Information

SummaryHow sensory information is processed by the brain can depend on behavioral state. In the visual thalamus and cortex, arousal/locomotion is associated with changes in the magnitude of responses to visual stimuli. Here, we asked whether such modulation of visual responses might already occur at an earlier stage in this visual pathway. We measured neural activity of retinal axons using wide-field and two-photon calcium imaging in awake mouse thalamus across arousal states associated with different pupil sizes. Surprisingly, visual responses to drifting gratings in retinal axonal boutons were robustly modulated by arousal level, in a manner that varied across stimulus dimensions and across functionally distinct subsets of boutons. At low and intermediate spatial frequencies, the majority of boutons were suppressed by arousal. In contrast, at high spatial frequencies, the proportions of boutons showing enhancement or suppression were more similar, particularly for boutons tuned to regions of visual space ahead of the mouse. Arousal-related modulation also varied with a bouton’s sensitivity to luminance changes and direction of motion, with greater response suppression in boutons tuned to luminance decrements vs. increments, and in boutons preferring motion along directions or axes of optic flow. Together, our results suggest that differential filtering of distinct visual information channels by arousal state occurs at very early stages of visual processing, before the information is transmitted to neurons in visual thalamus. Such early filtering may provide an efficient means of optimizing central visual processing and perception of state-relevant visual stimuli.

On the contours of apparent motion: A new perspective on visual space-time

1980 ◽  
Vol 39 (1) ◽  
pp. 27-35 ◽  
Author(s):  
T. M. Caelli ◽  
P. C. Dodwell
Keyword(s):  
Apparent Motion ◽  
Visual Space ◽  
Space Time ◽  
New Perspective

The Imaging of Crystal Structures and Crystal Defects

1978 ◽  
Vol 36 (3) ◽  
pp. 207-217
Author(s):  
J.M. Cowley
Keyword(s):  
Electron Microscope ◽  
Crystal Structures ◽  
Phase Contrast ◽  
Crystal Defects ◽  
Atom Density ◽  
Lack Of Information ◽  
Spatial Frequencies

The problem of "understandinq" electron microscope imaqes becomes more acute as the resolution is improved. The naive interpretation of an imaqe as representinq the projection of an atom density becomes less and less appropriate. We are increasinqly forced to face the complexities of coherent imaqinq of what are essentially phase objects. Most electron microscopists are now aware that, for very thin weakly scatterinq objects such as thin unstained bioloqical specimens, hiqh resolution imaqes are best obtained near the optimum defocus, as prescribed by Scherzer, where the phase contrast imaqe qives a qood representation of the projected potential, apart from a lack of information on the lower spatial frequencies. But phase contrast imaqinq is never simple except in idealized limitinq cases.

X-Ray Replication of Submicrometer Linewidth Patterns

1977 ◽  
Vol 35 ◽  
pp. 136-137
Author(s):  
Henry I. Smith ◽  
D.C. Flanders
Keyword(s):  
Electron Beam Lithography ◽  
Cross Sectional ◽  
X Ray ◽  
Electron Backscattering ◽  
Spatial Frequencies ◽  
Cross Sectional Profile ◽  
Carbon Foils ◽  
Sectional Profile ◽  
And Control ◽  
Soft Radiation

Scanning electron beam lithography has been used for a number of years to write submicrometer linewidth patterns in radiation sensitive films (resist films) on substrates. On semi-infinite substrates, electron backscattering severely limits the exposure latitude and control of cross-sectional profile for patterns having fundamental spatial frequencies below about 4000 Å(l),Recently, STEM'S have been used to write patterns with linewidths below 100 Å. To avoid the detrimental effects of electron backscattering however, the substrates had to be carbon foils about 100 Å thick (2,3). X-ray lithography using the very soft radiation in the range 10 - 50 Å avoids the problem of backscattering and thus permits one to replicate on semi-infinite substrates patterns with linewidths of the order of 1000 Å and less, and in addition provides means for controlling cross-sectional profiles. X-radiation in the range 4-10 Å on the other hand is appropriate for replicating patterns in the linewidth range above about 3000 Å, and thus is most appropriate for microelectronic applications (4 - 6).

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