[Sensitivity of different tissues of rats to the effects of a permanent magnetic field]. / O chuvstvitel'nosti razlichnykh tkanei krys k vozdeistviiu postoiannogo magnitnogo polia.

The biological effects of magnetic fields are known to be realized through the water structure of living organisms, which is the 60-90% of cells. In this respect the experiments investigating the magnetosensitivity of different tissues of rats by measuring the changes of hydration are of great interest. As it was shown, the tissues with higher hydration state (brain) were more sensitive to SMF influence, where depending on the exposure time the hydration of brain tissue increased. The hydration of the liver tissue, which was initially the least, was not changed.

[The olfactory orientation traits of white rats in a maze]. / Nekotorye svoistva oboniatel'noi orientatsii belykh krys v labirinte.

Some characteristics of olfactory behaviour of albino rats in three-arm maze have been studied. It was found that the olfactory discrimination of different food reinforcements may be elaborated in passages as long as 90 cm. Choice reactions were determined by olfactory, not visual, stimuli on their simultaneous presentation.

[A comparative analysis of spatial orientation in a changing environment in rats with differing preliminary experience]. / Sravnitel'nyi analiz prostranstvennoi orientatsii v meniaiushcheisia srede u krys s raznym predvaritel'nym opytom.

Comparison of rats behaviour with different preliminary experience in elaboration of the strategy of return to place of reinforcement was conducted. Significant differences in the number of selective replacements to the place of reinforcement in previous tests in experienced, inexperienced and naive rats were found. It was proved that decisive role in the appearance of the found differences played gained experience and the process of engram extraction from memory. Inhibition of search in naive rats and ability to selective use of strategies corresponding to situation in the experienced ones in condition of stress of permanent changes were shown.

[The singling out of the dominant in white rats during the acquisition of a win-stay strategy in a 3-arm maze]. / Vydelenie dominanty u belykh krys pri vyrabotke strategii vozvrashcheniia v trekhkhodovom labirinte.

Correlation of shift and stay reactions was studied in rats in the process of singling out of the win-stay dominant. It was found that in rat which had no previous experience in receiving reinforcement in multi-arm maze, both the shifts and stay reactions were observed with the dominance of the shifts. In experienced rats formation of the win-stay strategy using a new direction required learning and had three stages: the stage of initial dominant, of displacements and of singling out a new dominant. Formation of a new protracted dominant of win-stay could be gradual (through formation of short-term dominants) or uneven. At repeated changes of the reinforcement place both the tendency to uneven transfer and delayed periods in formation of the protracted dominant were observed.

[Characteristics of the role of spatial memory in the choice reactions of white rats]. / Osobennosti uchastiia prostranstvennoi pamiati v reaktsiiakh vybora u belykh krys.

Behaviour of the rats, previously learnt to come back to one and the same place of reinforcement was studied in conditions of periodical changes of this place. It was found that after detection of the new place of reinforcement, the rats could optimize their behaviour according to disposition of this place. Optimization of behaviour consisted in shifts of running direction towards the new reinforcement place and (or) in selective displacements before blinds, according to the places of reinforcement in the experiment. It is suggested that an increase of the role of working memory and apparatus of probabilistic prognosis at choice lies in the basis of optimization.

[Correlation of the visual and spatially oriented behaviors of white rats following the elaboration of a visual differentiation habit]. / Sootnoshenie zritel'nogo i prostranstvenno-orientirovannogo povedeniia u belykh krys posle vyrabotki navyka zritel'noi differentsirovki.

Correlation of spatial-motor and visually oriented reactions of white rats was studied by the method of three-side choice. It is shown that after acquisition of the habit of visual differentiation the visual orientation dominates only at taking feeding decision of passing to the passage. The choice of the direction of running to blinds and the choice of place of entering the passage do not depend on present visual signals location and do not reflect the state of visual differentiation habit, but are controlled by spatial memory.

[Dominant factors of rat behavior in response to stimuli in stages]. / Dominantnye faktory povedeniia krys v usloviiakh vybora étapnykh razdrazhitelei.

The adequacy of a modified variant of alimentary Y-maze method used by the authors was tested by studying the role of visual stage stimuli in reaction of free choice in rats. It is shown that the role of visual information is insignificant for acquiring the motor habit--finding of the shortest way to food. The dominant factors are: location of the shortest way, changing of which leads to a search behaviour by the method of "trials and errors", as well as ecologically adequate preference of edges to the center of the "distributor" and motor pretuning of the animal. Observed fixation of the choice of longer ways in comparison with the shortest one, and its stability may be explained by insufficient difference in the ways length before the reinforcement for the transformation of the habit of spatial-motor orientation into a visual one.

The structure of visual receptive fields of cat's pulvinar neurons.

Receptive fields of 382 neurons in the pulvinar were investigated. The observed receptive fields were classified according to the neurons’ responses to stationary flashing light spots positioned in different parts of the receptive field. New receptive field types with multiple discharge centers were observed. Neurons with these receptive fields generally responded with multimodal discharges to moving visual stimuli. The background illumination resulted in a decrease of the number of on-off and off receptive fields whereas the number of the on receptive fields became higher. In a majority of cases the receptive fields with multiple discharge centers lost their responsivness during background illumination. The changes in the receptive field sizes measured, by light spot in dark and light adapted conditions were attributed mainly to scattered light. The sizes measured by black stimuli under the same conditions remained constant.

Responses of cat's pulvinar neurons to moving visual stimuli.

Visually-driven pulvinar neurons were investigated by moving visual stimuli. Of a total of 256 observed neurons 25 percent were not sensitive to the movement of light spots, but revealed a vigorious activity during the movement of black objects. According to the response pattern elicited by the motion of objects through receptive fields, neurons were classified as follows: (a) directionally non-selective – 41 percent, (b) directionally selective – 28 percent, (c) multimodal – 29 percent, (d) suppressed-by-contrast type – 2 percent. Background illumination exerts different types of influences on the movement-evoked spike responses in the pulvinar neurons. Eighteen percent of the neurons were not affected by background illumination. Eight percent of the neurons were transformed from directionally non-selective into the directionally selective ones, some of which reversed their preferred directions during background illumination (5 percent). Activity of 15 percent of the neurons was facilitated and of 21 percent was suppressed during various levels of background illumination. Twenty three percent of the neurons lost their spike activity when the background illumination was switched on.

[Responses of cat pulvinar neurons to stationary visual stimuli]. / Otvety Neironov pul'vinara koshki na statsionarnye zritel'nye stimuly.

The activity of 130 neurons in pulvinar was investigated using static visual stimuli (light spots of different dimensions flashing in the center of receptive fields, and diffuse flashing light). 50 neurons of 130 did not respond to light stimuli but only to the movement of black stimuli. The majority of investigated neurons revealed "on--off" types of reactions to the flashing light spot, 14 neurons gave "on" responses, and 28 -- "off" responses. The receptive fields of pulvinar neurons had mainly homogenous structure without center and antagonistic surrounding, although some of them appeared to have concentric type of receptive fields. Some neurons revealed responses similar to those of neurons in the Clare--Bishop area. The responses of such neurons were the regular bursts of discharges during the time of stimulation which suggests the compound structure of receptive field with elements of different latency.

[Structure of the receptive fields of cat pulvinar neurons sensitive to photic stimulation]. / Struktura retseptivnykh polei neironov pulvinar koshki, chuvstvitel'nykh k svetomu razdrazheniiu.

The structure of receptive fields of 262 neurons was studied in pulvinar. Of 262 neurons 142 were investigated in detail for receptive fields using stationary and dynamic visual stimuli. The receptive fields were classified into 6 groups according to the responses to the stationary light stimuli. The first group contained on-off receptive fields (44 of 142), all the investigated parts of which produced on-off responses to the flashing light spot. The second group (42 of 142) included neurons with the off-reactions from the whole surface of the receptive field. The third group comprised the on-receptive fields (19 of 142). Eight receptive fields (the fourth group) were similar to the "simple fields" of primary visual cortex. The fifth group (10 of 142 neurons) was characterized as concentric having on-off centre and on or off surrounding. The sixth group (19 of 142) included receptive fields with multiple discharge centres, the receptive field surface having silent zones for both on- and off-responses. The neurons having such receptive fields responded by multimodaly distributed discharges during the stimulation by moving and stationary visual stimuli. The average latency of responses of most neurons in pulvinar was 40-70 ms, some neurons displaying shorter (20 ms) and some longer (130-160 ms) latencies.

[Responses of pulvinar neurons in cats to presentation of moving visual stimuli]. / Otvety neironov pulvinar koshki na pred''iavlenie dvizhushchikhsia zritel'nykh stimulov.

Responses of 114 pulvinar neurons to stimulation by moving light spots were studied. Most neurons (79) displayed background activity, the mean frequency of discharges being about 10-25 imp/s. 35 neurons showed no background activity, 41 neurons responded only to the movement of black stimuli, the rest being excited either by black or by light stimulus. The neurons were divided into two groups: those sensitive to the movement direction and those responding to two opposite directions of the movement by the equal numbers of discharges. A small number of neurons was observed responding to two opposite directions by regular bursts of spikes differently distributed in time (multimodal responses). Some neurons changed their nondirectional responses to the direction-sensitive ones after modifying the dimensions of the light spot.