[Effect of carbacholine and serotonin on the ATPase activity in synaptosomes of the projection and association areas of the feline cerebral cortex]. / Vliianie karbakholina i serotonina na ATP-aznuiu aktivnost' sinaptosom proektsionnoi i assotsiativnoi zon kory golovnogo mozga koshki.

Na, K-ATPase and Mg-ATPase activities were measured in the synaptosomes of the temporal auditory projection area and the frontal association area. Moreover, the effects of carbacholine and serotonin on those activities were investigated. Na, K-ATPase activity in the synaptosomes of the association area was shown to be reliably higher that in the synaptosomes of the projection area (11.02 +/- 0.45 vs 8.40 +/- 0.55 microM Pi/mg of protein hr; P less than 0.05). Mg-ATPase activity was higher in the second case as compared to the first one (11.40 +/- 0.38 vs 9.04 +/- 0.35; p less than 0.05). Carbacholine and serotonin (10(-8)-10(-3) M) were found to induce equal inhibition of Na, K-ATPase activity in the synaptosomes of both cortices (1 max = 25-30%, 1C50 = 0.2-0.3 microM) which is blocked respectively with atropine (10(-6) M) and methysergide (10(-6) M) and enhanced in presence of GTP (5.10(-5) M). The enzyme activity is also inhibited by the non-hydrolysable guanine nucleotide, GTP gamma S (10(-8)-10(-4) M), in the absence of the antagonists (1 max = 35-40%, 1 C50 = 0.02 microM). In the methysergide-containing medium serotonin exerts a dose-dependent stimulatory effect on Na, K-ATPase which is more pronounced in the synaptosomes of the association area (A max = 25%, A C50 = 0.05 microM). Mg-ATPase activity of membrane preparations is liable to be stimulated by both serotonin and carbacholine, stimulation being more pronounced in the synaptosomes of the association cortex as well (A max = 35%, A C50 = 0.2-0.3 microM). This effect is insensitive either to the antagonists of the corresponding receptors or to GTP. GTP gamma S does not cause alterations in the enzymatic activity. Na, K-ATPase is suggested to be coupled to muscarine and serotonin receptors in the synaptic membranes of both projection and association cortical areas via a GTP-binding protein. At the same time, the agonists of receptors mentioned above are presumably also capable to effect Mg-ATPase activity by the receptor-independent way.

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.

[The effect of microiontophoretic administration of acetylcholine on evoked activity of visual cortex neurons subjected to direct cortical stimulation]. / Vliianie mikroionoforeticheskogo vvedeniia atsetilkholina na vyzvannuiu aktivnost' neironov zritel'noi kory pri priamom korkovom razdrazhenii

Reactions of visual cortical neurons (field 17) were studied in unanesthetized curarized cats. Neuronal responses to direct electric stimulation of the 18th and the 19th fields were studied after microiontophoretic administration of acetylcholine--chloride through 2-channel microelectrodes. The acetylcholine effect upon the primary discharge and the first trace pause, was specifically organized. Some neurons reacted differently under acetylcholine to stimulation of the 18th and the 19th fields. Participation of acetylcholine in information processing by transcortical mechanisms, is discussed.

[Intra-analyzer temporary connections in the visual system]. / Vnutrianalizatornye vremennye sviazi v zritel'noi sisteme

The possibility of setting up intraanalyser temporary connections integrating the activity of various elements within the central part of the visual analyser at a neuronal level was studied in acute experiments on unanaesthetized immobilized cats. In the given model of temporary connection the unit activity in the lateral geniculate bodies (LGB) was investigated. Electrical stimulation of the superior colliculi was used as a conditioned stimulus, and illumination of the receptive fields of the studied LGB neurones, as an unconditioned one. In the process of conditioning, 10 to 11% of learning elements were revealed in LGB. The possibility is discussed of integration of learning elements into a definite microsystem achieving the process of temporary connection closing in the visual analyser in the course of conditioning.

[The role of polymodal synaptic influences in the formation of temporary connections in the microsystems of association cortex neurons]. / Znachenie polimodal'nykh sinapticheskikh vliianii dlia formirovaniia vremennoi sviazi v mikrosistemakh neironov assotsiativnoi kory

Significance of various sensory convergence of the neuronal activity was investigated in unanaesthetized cats in the process of elaboration of time connections. The elaboration of time connection was realized after studying neuronal responses elicited by the direct electrical or sensory stimulation (light, sound, tactile and proprioceptive stimulation). 42 per cent of all neurons and about 90 per cent of learned cells were found to be polysensory in the investigated cortex. The data obtained are considered from the standpoint position of the hypothesis on the microsystem principle of organization underlying time connection and convergence.

Acquired and inherent trace processes in the neuronally isolated cortex.

Trace processes in the neuronally isolated cerebral cortex of one hemisphere were analysed. EEG and unit activity of the isolated cortex at different times after the operation were investigated. Temporal connections in the isolated cortex were elaborated. Neurons fixing the stimuli traces were revealed. These neurons (23 percent of reactive neurons) form a microsystem of learning neurons.