[Fields of increased activity: the electrophysiological correlates]. / Polia povyshennoi aktivnosti: élektrofiziologicheskie korreliaty.

The peculiarities of the spatial-frequency organization of fields of increased activity in human cerebral cortex were evaluated by the index of the spatial potentials' synchronization. The method of topographic mapping of biopotential coherent structures permitted to reveal the principle of formation of the increased activity fields: the spatial interaction of coherent structures of different frequencies or quantum-frequency superposition of synchronous EEG-waves. This conclusion is based on a fact of the linear relationship between the intensity of a field of increased activity and a number of interacting coherent structures in it. The obtained data enlarge the ideas on the mechanisms of the origin of local activation processes in the human cerebral cortex and the possibility of their use for investigation of the neurophysiological base of the mental processes.

[Spectral correlation parameters of neocortical potentials in the rabbit undergoing paired isorhythmic stimulation]. / Spektral'no-korreliatsionnye parametry potentsialov neokoteksa krolika pri sochetanii izoritmicheskikh razdrazhenii.

At pairing of isorhythmic stimuli beyond the theta-rhythm frequency limits (3 and 8 Hz), in power spectra of EEGs of the sensorimotor and visual neocortical areas of rabbits, the frequencies are present both of the theta-range and of the stimulation frequency, in the background activity as well as during the stimulation. Both rhythms are in reciprocal relations. The frequency of the theta-rhythm approaches the frequency divisible by that of the stimulation. Under the action of the conditioned stimulus, crosscorrelation coefficients (CC) between the potentials of the areas under study decrease in most cases in comparison to their background values. Combination of the conditioned stimulus with the unconditioned one, leads approximately in equal number of cases to an increase or decrease of CC. After elimination of the stimuli, in most cases CC increases. CC of the background activity does not increase in the course of paired stimuli presentation though a conditioned response is being formed. At presence of stimuli frequency fluctuations simultaneously in the potentials of both areas, the rise of coherence function at this frequency does not occurs always. Thus, the above spectral-correlation parameters of rabbit's cortical potentials differ from those which arise at pairing of continuous nonrhythmic stimuli. This difference is probably due to different characteristics of the stimuli presented.

[Effect of a low-frequency alternating magnetic field on the formation of avoidance reflexes in the rat]. / Vliianie nizkochastotnogo peremennogo magnitnogo polia na formirovanie refleksov izbeganiia u krys.

Alternating magnetic field with induction of 3 mTl, frequency of 10 Hz, homogenous, with impulses of sinusoidal form and a vector with horizontal direction, produces an inhibitory effect on the formation of avoidance reflexes in white rats. The after-effect of the field lasts less than 1 hour.