It has been established in experiments on immobilized cats that somatic and interoceptive signals produce complex reorganizations of the spontaneous and evoked activity of visual cortex units. Either long diffuse changes of spike frequency or phasic reactions have been observed. The dynamics of sensory integration in the visual cortex is determined by unconditioned and conditioned mechanisms both of an intra- and interanalyser nature. Functioning of the microsystem of learning elements in the visual cortex is based on units capable of fixing the elaborated changes of evoked activity and constituting 18.6 percent of the total number of cellular elements in the visual projection cortex, responding to direct cortical stimulation. Microinophoresis of synaptically active agents has shown that complexely organized choline- and serotoninergic structures involved in the processes of unconditioned and conditioned interaction of heteromodal excitations are located in the visual cortex.

Acetylcholine↗

PubMedDate not supplied

[Closing an intra-analyzer temporary connection in visual cortex neuronal element microsystems].

The work was aimed at studying the formation of microsystems of learning neurones in the cortical visual zone of immobilized cats during elaboration of a temporary connection based on a combined stimulation of two its points in acute experiment. 18.6 per cent of the cells developed responses to the stimulus which had been ineffective before conditioning. The most numerous group consisted of units which displayed a complex form of elaborated response. Presumably the untis observed are part of a system of learning neurones controlling the intraanalyser interactions by the mechanism of temporary connection.

Animals↗

PubMedDate not supplied

[Compensation for disruptions of visual function in the dog after partial exclusion of the neocortex].

The recovery of visual disturbances provoked by partial neocortical deafferentation was studied in dogs with two sets of visual patterns: figures and differently oriented lines. The disturbances were more prominent, when the dogs had to solve the most complex visual tasks (6 stimuli showed to a dog simultaneously). There was a distinct recovery of figure recognition in the process of compensation, i. e. in 4--6 months after the neocortical deafferentation. On the contrary, recognition of oriented lines did not improve. Probably the differences between the two sorts of recognition mentioned above may be explained by various changes of their mechanisms' properties in the process of compensation.

Adaptation, Physiological↗

PubMedDate not supplied

[Microsystemic organization of neuronal interactions in the central units of the visual analyzer].

Neuronal interaction in superior colliculi (SC) and visual cortex (VC) was studied in acute experiments on immobilized unanaesthetized cats with simultaneous recording of unit activity in both structures. Polarization of cortical neurones produced activational changes in the level of impulse activity of SC neurones. In a considerable number of neurone pairs (38.4 per cent), fluctuations of the mean frequency and moments of spike discharge generation were in marked correlation suggesting their synphasic modulations. The data obtained are discussed from the point of view of microsystemic organization of central mechanisms of the higher nervous activity.

Animals↗

PubMedDate not supplied

[Compensatory reorganization of zone SI of the neocortex in the cat].

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Adaptation, Physiological↗

PubMedDate not supplied

[Use of a hierarchical cluster procedure for classification of neuronal responses to elaboration of conditioned reflexes].

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Classification↗

PubMedDate not supplied

[Plastic properties of cat visual cortex neurons].

Prolonged changes in receptive fields of cells in the visual cortex were studied in different periods after ablation of projection connections of the cortex in the contralateral hemisphere. Cellular activity was recorded in non-anaesthetized immobilized cats in different periods (from 2 hours to 14 months) after ablation. It was found that 6-7 months after unilateral section of projection fibres in the cortex, photic sensitivity of neuronal elements markedly decreased in the field 17, whereas cells in fields 18 and 19 retained their responses to commonly used photic stimuli. The paper discusses the problem of different roles of retino-geniculo-cortical and retino-tecto-thalamo-cortical systems in the compensation of impaired visual function.

Animals↗

PubMedDate not supplied

[The effect of neuropeptides on the processes of higher nervous activity in primates. The action of cyclic analogs of enkephalins on the behavior of lower monkeys].

The influence of 2 cyclic enkephaline analogues (IVS-43 and IVS-46) on group and individual behaviour of rhesus and baboon monkeys was studied. The effect of IVS-46 on competitive and operant goal-directed behaviour of the monkeys was expressed. Possible mechanisms of functional reorganization of the higher nervous activity of primates under the influence of neuropeptides are discussed.

Animals↗