[Problem of visual segmentation and spatial-frequency filtration].

The analysis of the visual segmentation problem involved questions concerned with a signal description as a result of linear filtering, nature following nonlinear transformations, and possible role of a spatial attention in pooling. Different approaches to the visual segmentation problem are compared. Our data suggest a model of visual segmentation.

[Size as a parameter for tuning visual attention].

The ability of visual attention to tune to the stimulus size (when this size could not be described by spatial frequencies) was studies. Sinusoidal gratings with frequencies of 1.5, 3, and 6 cycle/degree were used as test stimuli.

[Biotropic effects of electromagnetic fields: benefit or harm?].

An overview contains the analysis of controversial literary data on possible therapeutic and pathogenic effects of electromagnetic fields on humans. The non-specific character of body shifts induced by electromagnetic fields with a prevalence of adaptive reactions at the onset and an emergence of dysadaptive processes during extremely long exposure was displayed. The leading role in the development of a therapeutic or pathogenic effect is played by the functional characteristics of an individual postulating the interaction of cumulative and adaptive processes in the body during long-term exposure in an electromagnetic field.

[Morphometric evidence of activation of axo-somatic synapses during administration of delta sleep-inducing peptide].

Computed morphometry proved activation of neocortex layer III-V axosomatic synapses. This is evident from an increase in the mean plasmalemma length, that in the active synapse zones on neurone bodies and width of the synaptic cleft, this being induced by a single intraperitoneal administration of delta-sleep-inducing peptide. The activation of the axosomatic synapses correlates with elevated GABA levels in the cerebral hemispheres cortex.

[Effect of delta-sleep peptide on the ultrastructural features of the rat sensomotor cortex].

The performed studies have shown that injection of DSIP causes an activation of nuclear apparatus and plastic metabolism in III-Y layer of the rat cerebral cortex. The activation of axo-axon and axosomatic synapses indicates the modulation of inhibitory processes in the cerebral cortex.

[Role of functional asymmetry of the cerebral hemispheres in organization of an instrumental alimentary conditioned reflex in cats].

During instrumental alimentary conditioning in cats the speed of reflex stabilization depended on the correspondence between the dominant leg's lateralization and the side of the lever, which the animal had to press in response to the signal. When the lever was on the side of the dominant leg, the speed of the conditioning was greater than in the absence of such correspondence. Functional switching off (KCl) of the cortex of any hemisphere at the stage of reflex stabilization does not disturb the instrumental reaction.

[Neuronal organization of a focus of unconditioned excitation in the cat sensomotor cortex].

The impulse activity of sensorimotor area neurones, situated near the point of its direct electrical stimulation used as a reinforcing stimulus, was studied in cats. The rearrangement of impulse activity during reflex elaboration consisted in the reduction of frequency of background activity, in changes in the character of neuronal reactivity and of the pattern of response to the signal and reinforcing stimuli. During the reflex elaboration the percentage of polymodal neurones increased.

[Participation of neurons from symmetrical parts of the sensomotor cortex in conditioned reflex activity].

Spike activity of the symmetrical points of the sensorimotor cortex was studied in the course of formation and extinction of a defensive conditioned reflex in cats. In the process of pairings the impulse responses in the hemisphere contralateral to the paw stimulated with electric current (reinforcement) increased, and were inhibited in the ipsilateral hemisphere. Extinction of the reflex or functional switching off of the contralateral hemisphere restored the conditioned reactions of the ipsilateral hemisphere neurones.

[Informational characteristics of the impulse activity of cat sensomotor cortex neurons during elaboration of a defensive conditioned reflex].

Manifestations of the dynamics of defensive conditioning were studied in the cat sensorimotor cortical units. It has been shown that the process of learning is linked to the dynamics of the amount of total and useful information present in the evoked spike responses to a conditioned stimulus. As the pairings continue, the amount of useful information increases in reactions to conditioned or unconditioned stimuli and in the period preceding the conditioned stimulation.

[The neuronal organization of a focus of conditioned excitation in the cat sensory-motor cortex].

The activity of single units in the focus of conditioned excitation was studied during defensive conditioning to direct electrical stimulation of the cat sensorimotor cortex. Reorganizations of spike activity set in during the period of reflex elaboration, were manifest in the increased number of excited neurones and those which respond both to the conditioned and unconditioned stimuli. In the course of elaboration, the inhibitory phase of unit responses to direct electrical stimulation of the sensorimotor cortex was reduced, while the frequency of background unit spike activity was enhanced.