[Neuronal mechanisms of sensory integration in the visual analyzer system].

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.

[Effect of serotonin on neuronal activity in the visual region of the cerebral cortex evoked by direct cortical stimulation].

Neuronal responses in cortical area 17 evoked by direct stimulation of areas 18 and 19 were investigated in acute experiments on unanesthetized cats. It was found that microiontophoretic application of serotonine changed late components of phasic neuronal responses and influenced the diffuse-tonic responses. The question on serotonin participation in trace responses and regulation of the excitability of visual cortex neurons is discussed.

Effect of microiontophoretic application of acetylcholine on visual cortical evoked activity to direct cortical stimulation.

Responses of visual cortical neurons (area 17) to direct cortical stimulation of visual areas 18 and 19 were investigated in acute experiments on adult unanesthetized cats, immobilized with diplacin, under local anesthesia, after microiontophoretic application of acetylcholine. Selectivity of the action of acetylcholine on the individual components of the unit responses to direct cortical stimulation was established. The role of acetylcholine as mediator of information in the mechanisms of transcortical interneuronal interaction within the visual system is discussed.

[Effect of microiontophoretic application of serotonin on the background impulse activity of visual cortex neurons in unanesthetized cats].

Sustained spike activity of neurones in the visual area (field 17) of the cerebral cortex and its changes induced by microionophoresis of serotonin was studied in experiments on unanaesthetized cats immobilized with diplacine. Neurones of field 17 with sustained activity are characterized by non-rhythmic, low-frequency discharges of a mixed type. 55 per cent of the studied neurones were sensitive to serotonin.