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The purpose of this study was to investigate the relationship between the morphological parameters of the fovea, foveola, and foveolita of the human eye and the psychophysical and electrophysiological indices of the sensory and cognitive activities. We investigated the relationship between the sizes of these structures and the resolving power of the eye, as well as the influence of the size on the amplitudes and latent periods of various evoked potential components. It has been found that the foveola diameter affects the latent periods of the early waves of the visual evoked potentials (component P100) in the occipital areas. Our data confirm the effect of the foveola diameter on the parameters of cognitive processes during reading. In particular, it has been found that a larger fovea size provides the perception of a higher amount of printed characters.

Biederman and co-authors [1, 2], have shown that the priming effect in the long-tirn priming paradigm does not depend on the difference between the angular sizes of the test stimulus and the primer. However, these two and other similar works (both with long-time and short-fime priming paradigms) studied a small range of the angular sizes of stimuli. In Vakhrameeva et al. [3], it has been shown that there exist two perceptionally different size ranges: perception of the objects with angular size varying from 1-1.5 to 50 deg was found to be invariant, but for the objects which angular size is less than 1-1.5 deg (depending on object class and task) their perception is no longer invariant. In this work we have investigated the presence of priming effect in match-to-sample task with such a difference in the angular sizes of a primer and a test stimuli, when the sizes of the primer (about 4 deg) and the test stimulus (about 0.5 deg) belong to those different physiological size ranges. The sample stimulus was presented with and without the noise superposition. It has been shown that the priming effect is suppressed when the size difference between the primer and the test stimulus is large. A congruent primer can give a positive impact on the recognition of the test objects, but this takes place under viewing conditions complicated by the noise superposition.

The objective of this research was to compare the features of the shape of the foveolar area with the characteristics of eye movements in reading. To measure the size of the fovea, we used the method of optical coherence tomography of the retina. Based on this method, the diameter of the upper part of fovea (fovea diameter) and fovea bottom (foveola diameter) were determined. We found a negative correlation between the fovea diameter and fixation duration and positive correlations at the level of tendency between the foveola diameter and the number of saccades performed and between the foveola diameter and the number of characters captured by eye per fixation.

Biederman and co-authors [1, 2], have shown that the priming effect in the long-tirn priming paradigm does not depend on the difference between the angular sizes of the test stimulus and the primer. However, these two and other similar works (both with long-time and short-fime priming paradigms) studied a small range of the angular sizes of stimuli. In Vakhrameeva et al. [3], it has been shown that there exist two perceptionally different size ranges: perception of the objects with angular size varying from 1-1.5 to 50 deg was found to be invariant, but for the objects which angular size is less than 1-1.5 deg (depending on object class and task) their perception is no longer invariant. In this work we have investigated the presence of priming effect in match-to-sample task with such a difference in the angular sizes of a primer and a test stimuli, when the sizes of the primer (about 4 deg) and the test stimulus (about 0.5 deg) belong to those different physiological size ranges. The sample stimulus was presented with and without the noise superposition. It has been shown that the priming effect is suppressed when the size difference between the primer and the test stimulus is large. A congruent primer can give a positive impact on the recognition of the test objects, but this takes place under viewing conditions complicated by the noise superposition.

The aim of the present work was to assess the range of angular sizes of fragmented images of objects at which perception of the images was scale-independent. Measurements were made of human subjects' recognition thresholds for the shapes of the objects over a wide range of angular sizes (0.19-50 degrees). The experiments used the Gollin test--a method for studying the recognition of fragmented outline images of objects with which the observer is familiar. The results obtained demonstrated that there is a wide range of angular sizes, from 1.0 degrees to 50 degrees, over which the perception thresholds of incomplete outline images do not change with changes in size, along with a narrow range of stimulus sizes, 0.19-1.0 degrees, over which there is a significant size dependence. We suggest that the increase in thresholds and the failure to recognize images of small size occur as a result of an increased contribution of sampling noise at the level of the human retina.

The work of an operator in solving two classification problems when working with one image alphabet is studied. From ninety visual stimuli, half of the images contained animate objects, and the other half contained inanimate objects. The first task was to classify the images according to a semantic attribute—whether they contained an animate or inanimate object. This alphabet of stimuli was then subjected to wavelet filtering in a low- and high-spatial-frequency region, regardless of semantic significance. The second task was to classify the stimuli according to a physical attribute—a blurred or unblurred object in the image. Electrophysiological monitoring of the operator’s work—recording of the induced visual potentials from the entire surface of the head—made it possible to detect that, from the beginning of the stimulation until the organization of the motor response, parallel processing of the observed signal occurs according to the different semantic and physical attributes. The responses of the temporal and frontal sections of the brain associated with the semantics of the images are distinguished, even under those conditions in which the subject’s task was to classify the physical properties of an image of an object.

It is well known that an important function of binocular vision is to increase the SNR. When a signal simultaneously arrives along two channels, it is summed if the channels are statistically independent. The binocular visual acuity can then theoretically be increased by comparison with the monocular value by a factor of 2, or 1.4. This paper gives the results of experiments to measure the visual acuity by means of Landolt rings. It is established that binocular visual acuity is greater than monocular by a factor of 1.3 on the average. It is assumed that this can be associated with internal multiplicative discretization noise at the level of the retinal receptors. This result is important for understanding image processing in different channels of the visual system.

The development of methods of digitally synthesizing and processing images has made it possible to use the methods of iconics to deliberately create test images that selectively activate various structures of the visual system. The methods of processing neurophysiological data, including not only images of the activity of the entire brain but also so-called neuroimaging methods, have made it possible to discriminate the brain structures activated as a result of this selective action. The goal of this study is the spatiotemporal localization (mapping) of the regions of the brain that participate in making decisions concerning the shape of textures. It is established that a subject’s reaction time correlates with the degree of ordering of the textures and with the latency of the late components of the induced potentials in the frontal cortex. The time for a person to make decisions in the task of recognizing a specified class of textures is thereby determined. Mapping of the brain by the method of functional magnetic-resonance tomography showed that the activity of the brain in the process of making decisions involving recognition occurs in the frontal cortex of the human brain.