[The retinotopic organization of the posterior suprasylvian area of the cerebral cortex in the cat]. / Retinotopicheskaia organizatsiia zadnei suprasil'vievoi oblasti kory mozga koshki.

Posterior suprasylvian area (PSA) is one of the extrastriate visual structures of the cat cortex. Representation of the visual field in the PSA has been investigated by the mapping method. Results of experiments revealed that receptive fields (RF) of the PSA neurons were located mostly in the upper contralateral quadrant of the visual field. About 10% of RF were located in the upper ipsilateral quadrant of the visual field. In the upper PSA (21a, 21b) area centralis is mainly represented including the space of the radius of 20-30 degrees of the visual field. In the lower PSA (20a, 20b) more peripheral part of the visual field was represented. The experiments did not confirm essential differences in the retinotopic organization between areas 20a and 20b, 21a and 21b. Proceeding from the presented experiments the suggestion is put forward that PSA consists of two main areas (21 and 20) without dividing into subareas.

[Inhibitory components in responses of neurons of the lateral suprasylvian area of the cat cortex]. / Tormoznye komponenty v otvetakh neironov lateral'noi suprasil'vievoi oblasti kory koshki.

Inhibitory components of neuronal responses to moving visual stimuli in the lateral suprasylvian area of the cat cortex have been studied. Comparison of PST histograms of responses to two opposite directions of the movement allows revealing changes in the spatial localization of discharge centres in receptive fields relative to the movement direction. In all neurons investigated which revealed monotonous stationary structure of receptive fields no subregions coincidental with the inhibitory components of the responses are found. The presented experiments have promoted a conclusion that inhibitory components of responses of observed neurons could represent aftereffects following excitation of the cell when the stimulus is crossing the discharge centre of the receptive field.

[Organization of the substructure of the receptive fields of neurons of the lateral suprasylvian area of the cat cortex]. / Organizatsiia substruktury retseptivnykh polei neironov lateral'noi suprasil'vievoi oblasti kory koshki.

The substructure of receptive fields of the lateral suprasylvian area neurons was investigated in cats. It was shown that the majority of receptive fields investigated were organized of subelements with different qualitative characteristics according to their responses to moving visual stimuli. With the unmasking method of stimulation, small amplitudes of the motion evoked, as a rule, directional responses, whereas with the masking method the same amplitude of the motion produced nondirectional responses. Some receptive fields of the investigated neurons responded vigorously to the motion of borders of the visual stimuli. The heterogeneity in organization of the substructure of the receptive fields was explained by the convergence of different inputs to the investigated neurons.

[Dynamic and static features of the receptive fields of neurons of the lateral suprasylvian area of the cat cortex]. / Dinamicheskie i staticheskie osobennosti retseptivnykh polei neironov lateral'noi suprasil'vievoi oblasti kory koshki.

Dynamic and static properties of neurons were investigated in lateral suprasylvian area of cat. It was shown that neurons with different dynamic characteristics could have the receptive fields with similar static organization. Thus strict correlation between static and dynamic organization of the receptive fields of suprasylvian neurons were not observed. The majority of black-sensitive neurons appear to have off-fields. The contrast reversal test of moving stimuli revealed that the generation of responses both to the light and to the black stimuli was performed by the same part of the receptive field and was not conditioned by the spatially separate on- and off-discharge centers in the receptive field.

[Characteristics of neurons of the lateral suprasylvian region of the cat cerebral cortex sensitive to the movement of black stimuli]. / Osobennosti neironov lateral'noi suprasil'vievoi oblasti kory mozga koshki, chuvstvitel'nykh k dvizheniiu chernykh stimulov.

Visually sensitive neurons of the lateral suprasylvian area were investigated in cats with pretrigeminal brain stem sections. Nearly 25% of a neuron population responding to the visual stimuli revealed great sensitivity to movement of black stimuli across their receptive fields. These neurons were called "black-sensitive". As a rule, they had either a low-level or no background activity. Nearly 89% of these neurons revealed direction-selective properties. The most characteristic feature of "black-sensitive" neurons was a change in response patterns with the reversion of the stimulus contrast.

[Receptive fields of lateral suprasylvian neurons in the cat]. / Retseptivnye polia neironov lateral'noi suprasil'vievoi oblasti kory mozga koshki.

The receptive field structure of single neurons in lateral suprasylvian area was investigated in cat. Receptive fields were of larger sizes comparing with visual cortex (up to 2000 sq. deg.). The dimensions of receptive fields measured by black objects and light spots revealed differences, the receptive fields being usually larger when black objects were used. The experiments showed that the visually sensitive neurons of the lateral suprasylvian area could be activated by stationary flashing light stimulus. The neurons were qualified in three groups as on, off and on-off. Distribution of the activity all over the receptive field surface was investigated using flashing light spots. Receptive fields with the plural discharge centres were revealed.