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V D Glezer

Publications and source records attributed to V D Glezer.

66 records · Page 4Linked to original sources
PubMedDate not supplied

[Adjustment of the cat visual cortex receptive fields to certain spatial frequency bands within definite ranges of movement frequencies of stimulating gratings].

Reactions of simple and composite receptive fields (RF) of the 17th and 18th fields of cat's visual cortex to grating with various spatial frequency moving through the field with different velocities were studied. It has been shown that for each RF the velocity range is revealed within which spatial-frequency selectivity of RF exists. The narrow-band tuning for high frequency RF exists in the range of low velocities, and for low frequency ones in the range of higher velocities.

Animals↗
PubMedDate not supplied

[Mechanisms of visual generalization].

The phenomenon of differentiations transfer from grids of different frequency and orientation to bars of different width and orientation was examined by the method of alimentary motor conditioned reflexes elaborated in free behaving dogs. After formation of differentiations of rectangular high-contrast grids by spatial frequency or orientation, transfer to single lines with the width equal to the width of bars forming the grids, leads to a broadening of the range of frequencies and orientations eliciting a positive response. Due to this fact, differentiations disappear or considerably worsen. The obtained results do not agree with the detector hypothesis according to which a part of receptive fields of the visual cortex are detectors of borders or bars of different width and orientation. But the results are predicted quantitatively by the hypothesis of description of images by receptive fields of the visual cortex as by two-dimensional filtres tuned to different spatial frequencies and orientations.

Animals↗
PubMedDate not supplied

[Model of local spectral description of images in the visual system].

On the basis of experimental evidence presented earlier a model of local spectral analysis of the image performed by the complex receptive fields of the visual cortex has been proposed. An essential feature of the model is that the generalized piece-wise Fourier transform is performed not over the image luminance function but over the logarithm contrast function resulted from analysis of the image by the round receptive fields of the preceding levels. Such an assumption removes a number of experimental objections offered against the hypothesis of two-dimensional Fourier transform in the visual system. The consequencies from the piece-wise expansion in a series of basic functions have been considered and among them: the channel frequency characteristics which can have more than one maximum; the possibility of describing the image by a limited number of channels with overlapping frequency characteristics.

Fourier Analysis↗
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[Spatial-frequency characteristics of receptive fields of the cat visual cortex on homogeneous and nonhomogeneous backgrounds].

Spatial frequency characteristics of the cortical receptive fields obtained with sinusoidal gratings were investigated on the background formed by orthogonally oriented gratings or on the homogenous background. The results correspond to the conjecture that the receptive fields as spatial frequency filters are linear independent in orientation.

Animals↗
PubMedDate not supplied

[Spatial-frequency characteristics of the receptive fields of cat visual cortex with different rates of stimulus movement].

Velocity ranges exist for complex and simple receptive fields of cat's visual cortex. In these ranges there is a narrow band frequency tuning. In these velocity ranges the location of the maximum on frequency characteristics is constant and does not depend on the velocity of stimulating lattice movement. An increase of the movement velocity brings about a reduction of the reaction value of the receptive fields and a disappearance of the narrow band tuning expressed in the optimal velocity range.

Animals↗