[Mechanisms of the formation of a neuronal reaction of the lateral geniculate body in the cat to moving stimuli]. / Mekhanizmy formirovaniia reaktsii neironov naruzhnogo kolenchatogo tela koshki na dvizhushchiesia stimuli.

Mechanisms of response to a moving stimulus were analysed in a model of neuronal net with space-time negative feedback. A role of different couplings and the effect of their weight functions parameters are described. The inadequate space couplings had to be wider than adequate ones whereas the time parameter of inadequate couplings had to be lesser than that of adequate couplings.

[Model of mechanisms forming reactions of cat's lateral geniculate nucleus neurons to moving stimuli]. / Model' mekhanizmov formirovaniia reaktsii neironov naruzhnogo kolenchatogo tela koshki na dvizhushchiesia stimuly.

The neurons net with a space-time negative feedback is described by the integral equations system. Solution of the system is made numerically. Mechanisms of LGN neurons reaction (for the cat) are investigated by means of such model. The model and experimental results are compared.

[Response of lateral geniculate body neurons to moving light bands in cats]. / Issledovanie otvetov neironov naruzhnogo kolenchatogo tela koshki na dvizhushchiesia svetlye polosy.

A number of electrophysiological investigations revealed that the relief of activity (RA) arising in outputs of overlapping receptive fields (RFs) of the LGB reflects the form of test image. The RA was reconstructed by the responses of single neurons. The bars' width and velocity of their movement varied. Dependence of RA size on the image size was approximated with the aid of the logarithmic function for the small angle images (less than 1.5 +/- 2.0 angle degrees) and of the power function for larger sizes. The interrelationships obtained take place within the scope of motion rates from 0.6 to 30 angle degrees per second. This scope of motion depends on the eccentricity of RFs centers in respect to the area centralis.

[Convergence of activating connections of retinal on- and off-ganglion cells on lateral geniculate body neurons]. / O konvergentsii vozbuzhdaiushchikh sviazei on- i off-gangliozonykh kletok setchatki s neironami naruzhnogo kolenchatogo tela.

On- (off-) central neurons of the retina and lateral geniculate body (LGB) generate off- (on-) responses to stimuli acting upon the periphery of their receptive fields (RFs). We have found neurons with equal on- and off-responses to testing of the central part of their RFs. RFs of such neurons consist of overlapping on- and off-areas. The type of their responses can change on alteration of the stimulus parameters or under influence of light adaptation. A number of the LGB neurons seem to have activating inputs both from on- and off-central ganglionic cells of retina.

[Experimental study of the visual system using unidimensional Walsh gratings]. / Eksperimental'noe issledovanie zritel'noi sistemy s pomoshch'iu odnomernykh reshetok Uolsha.

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.

[Model of local spectral description of images in the visual system]. / Model' lokal'nogo spektral'nogo opisaniia izobrazhenii v zritel'noi sisteme.

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.

Characteristics of excitation and inhibition of the receptive fields of the retina and lateral geniculate body.

The process of excitation and inhibition in the receptive fields (RF) of the ganglion cells and lateral geniculate body (LGB) of the cat were examined. The extent of the dependence of the magnitude of excitation and inhibition in RF on stimulus intensity was determined. This dependence is a power function with power indices of 0.15--0.20 (LGB) and 0.3--0.5 (retina) for excitation and 0.2--0.3 (LGB) and 0.5--0.6 (retina) for inhibition.

[Analysis of spatial frequency characteristics of complex receptive fields]. / Analiz prostranstvennykh chastotnykh kharakteristik slozhnykh retseptivnykh polei

The difference fB2-fB1=deltaf and ratio fB2/fB1=R of the bandwidth boundary frequencies fB1, fB2 of spatial frequency characteristic of complex receptive field depends on the size of RF and spatial structure of excitatory and inhibitory zones. deltaf and r are independent of the weighting functions of excitatory and inhibitory zones. The theoretical value of r is similar to data which was obtained in psychophysical and physiologycal experiments. The dependence of contrast sensitivity on spatial frequency can be explained by dependence of the envelope of weighting functions of exitatory (inhibitory) zones on the spatial frequency.

[Spectral characteristics of stimuli and responses in a complex receptive field]. / Spektral'nye kharakteristiki stimulov i otvety slozhnogo retseptivnogo polia

Responses of a complex receptive field of visual cortex of the cat are determined by the energy of stimuli in the band pass of equivalent space frequency characteristic of the receptive field. This is a proof that the complex receptive fields are spatial frequency band pass filters.

[Image description at the level of the external geniculate body]. / Ob opisanii izobrazhenii na urovne naruzhnogo kolenchatogo tela

The responses of the receptive fields of the cat lateral geniculate body were investigated with a different position of the light stimuli in the receptive field. The stimuli were of the cross shape. On the basis of the obtained data the relief of excitation of the overlapping receptive fields was reconstructed. It is shown that at the level of the lateral geniculate body there exist a copy of the light stimuli. The description of the image is formed as a relief of excitation which changes in time. The magnitude of the excitation depends on the contrast of the stimuli.

[Role of functional reorganization of the receptive fields in forming a relationship between visual acuity and pupil diameter]. / O roli funktsional'noi perestroiki retseptivnykh polei v formirovanii zavisimosti ostroty zreniia ot diametra zrachka

A visual acuity of the human eye with correction is independent of pupil diameter within the 8 mm to 2 mm. The effect of functional reorganization of receptive fields compensate the influence of the change of optical quality of the eye as it is shown with the help of a model.