[Mechanism of responses to movement in the visual cortex neurons unresponsive to light flicker]. / O mekhanizme vozniknoveniia otvetov na dvizheniia u neironov zritel'noi kory, ne otvechaiushchikh na svetovye mel'kaniia.

The responses to moving and stationary stimuli in cat's striate cortical units were studied. Two stationary light bars, one located in the receptive field centre, and another--in the periphery, were used. The sequence of presentation and the time-interval between the stimuli varied thus making the presentation of a pair of stationary bars an analogue of a moving stimulus. Responses occurred in the neurons previously unresponsive to stationary stimuli when two stationary stimuli were presented successively in certain order. A model is proposed explaining the occurrence of responses to moving stimuli in the neurons, unresponsive to stationary ones.

[Study of the mechanism of directionality of the receptive fields of the visual cortex in the cat]. / Issledovanie mekhanizma direktsional'nosti retseptivnykh polei zritel'noi kory koshki.

The responses of directional-sensitive striate cortex neurons to two light bars one of which was located in the centre of the receptive field and the other--in the inhibitory zone were investigated in unanaesthetized cats. The order of presentation and the time intervals between the stimuli varied; so the presentation of the pair of stationary bars was an analog of a moving stimulus. It was shown that the inhibitory off-zone located on the side of the preferred direction of movement is characterized by an early inhibitory phase followed by a phase of disinhibition and by the second inhibitory phase. The presentation of a pair of stationary bars with different time intervals between them elicited inhibition when the central zone stimulation coincided with the inhibitory phases and facilitation when it coincided with the disinhibitory phase. For the inhibitory off-zone located on the side of the null direction no disinhibitory phase was found. The significance of the time characteristics of the inhibitory zones for the appearance of directional sensitivity in striate neurons is discussed.