PubMed Health⌕ Search

Biomedical subjects

N B Kostelianets

Publications and source records attributed to N B Kostelianets.

16 recordsLinked to original sources
PubMed1978

[Experimental study of the visual system using unidimensional Walsh gratings].

Threshold characteristics of the visual system for an orderly set of the Walsh aperiodic gratings were estimated prior to and after adaptation. Narrow--band channels of Walsh with the band width about 1 octave by the Walsh scale of function orders, were revealed. The model of summation by the power of spectral sinusoidal components of the Walsh aperiodic lattices well accounts for the data on gratings the Walsh aperiodic gratings.

Adaptation, Physiological↗
PubMedDate not supplied

[Shape recognition and image orientation in young children].

A comparison was made of recognition of images in the direct and inverse "top-bottom" orientation. A child two and a half years old was to find the test image on the response card or to give a verbal reply. The verbal responses have shown that the child identifies well both the shape and orientation of the images. In experiments with the response card, the presentation of images in inverse orientation did not result in any mistakes in recognizing the shape nor did it prolong the latency of the reaction, and no correlation was found between the orientation of the presented and the response figures. A child trained to find images of both similar shape and orientation is incapable of indicating properly the orientation of an image presented for a limited time period. These facts are interpreted in terms of the hypothesis of multichannel transfer of information about the pattern in the visual system.

Form Perception↗
PubMedDate not supplied

[Visual recognition with early and delayed observer tuning to a specific set of images].

It has been shown in psychophysiological experiments that re-tuning of the observer's visual system from a long set to a short one improves recognition to a greater extent after an anticipating signal about the set than after a delayed one. The change of the anticipating signal to a delayed one increases the number of "I don't know" responses, while the number of errors of confusing resembling figures remains unchanged. Temporal limitations of processing of the information about the stimulus increases the number of confusion errors. The degree of the observer's training reflects upon the number of errors; the number of "I don't know" responses does not change. The facts obtained attest that two processes are involved in recognition: one of them is sensitive to the position in time of the signal about the set and does not depend on training. The other process, on the other hand, does not depend on the signal position in time and changes depending on training. It is assumed that the first process is a complete element-to-element description, while the second one is a classification process.

Form Perception↗
PubMedDate not supplied

[The estimation of the direction of uniform and nonuniform movement and the alpha-rhythm EEG].

In experiments with 7 human observers the recognition of side and direction of the even and non-even (compensating the magnification factor) light motion in the left or right visual hemifield and to or from the fixation point was studied. The onset of the movement coincided with different phases of the EEG alpha-wave in the occipital region. In a control study stimuli were presented irrespectively to alpha-wave phases. Synchronization of non-even motion with some of the alpha-wave phases lead to an increase of its recognition probability and relative shortening of the response latency for directions from the center of gaze, while opposite directions became worse recognized and evoked relatively long-latency responses. Recognition of the even motion was not changed in experiment in compare with control. The obtained date are discussed in relation to Pitts and McCulloch (1947) hypothesis on a periodical (with alpha-wave frequency) scanning wave spreading over the visual cortex.

Adult↗