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Biomedical subjects

K A Nikol'skaia

Publications and source records attributed to K A Nikol'skaia.

At least 19 recordsLinked to original sources
PubMed2003

[Psycho-emotional manifestations in rats with hippocampal lesions].

The study aimed at revealing psycho-emotional manifestations of Wistar rats in a problem situation when they had to solve a food-getting task in a multi-alternative maze. Bilateral lesion of dorsal hippocampus did not affect the learning process while the pattern of psycho-emotional manifestations changed in all the animals irrespective of their individual properties. The pverall effect was manifested in flatness of psycho-emotional responses as a result of reduction of extreme forms of both passive and active stress responses. Individual effects depended on the behavioural phenotype. Hippocampus lesion in initially excitable rats (10%) resulted in reduction of active stress responses (act/pass = 0.35/0.5 instead of 1.0/0.4 in control). Hippocampus lesion in initially inhibited rats (30%) did not affect the basic pattern of psycho-emotional responses, while in the rats with initially depressed cognitive activity (60%) it resulted in decreasing of passive and increasing of active stress responses (act/pass = 0.45/1/4 instead of 0.3/1.9). The findings suggest that hippocampus takes part in the psycho-emotional responses while the individual psycho-emotional pattern is determined by the morpho-functional features responsible for organisation of a psycho-emotional condition.

Animals↗
PubMed2003

[Features of active control used in pharmacological studies].

The effects of 5 injections of salt solution and unfractionary heparin in dose 0.36 microgram/kg (Serva, Germany 10 kDa, activity 180 U/mg) have been studied in Wistar rats. It was found that two injections of salt solution were enough to form a stable defensive state in all rats which was manifested as an expectation of pain in tail-flick testing. The defensive motivation provoked by the injections negatively influenced the learning process as saline-induced rats refused to solve a food-getting task in a problem situation. Explorative and locomotor activities were depressed in these rats and were accompanied by numerous stressful and neurotic-like manifestations. Unlike saline-rats, practically all heparinized-rats instead of 45% of intact rats were able to solve a cognitive task despite the injections. Anxiety was decreased, but sensitivity to different external factors was increased in the heparin-induced rats. Formed habit in these rats was characterized by a high organization and stability. However, the majority heparin effects in tail-flick test were discovered when comparing the heparin-induced rats with intact ones and were not observed in comparison with the saline-rats. It is suggested that the saline-control should be considered as specific control having defensive features which are necessary to take into account in interpretation of effects of other pharmacological preparations.

Animals↗
PubMedDate not supplied

[The learning characteristics of rats under free-choice conditions].

The ability to organize a four-link operant food-procuring habit in a multiple alternative maze using the free-choice method was studied in albino rats. Three types of animals were observed which were different in the character of learning. The learning curve of 20% of rats had of exponential character (type I). Some animals (37%) acquired the skill through "insight" and the process of learning in these cases could be described by a logistic regression function (type II). The remaining rats (43%) refused from solving the intricate task and were able to acquire only the simplest form of a response, i.e., running to feeders. It is suggested that learning differences between the I and II types of animals may be associated with different strategies of problem solving: "procedural" (algorithmic) and "conceptual" (semantic).

Animals↗
PubMedDate not supplied

[The neurochemical and behavioral indices of an acquired alcohol craving in rats under conditions of information loading].

The state of neurotransmitter systems was studied in the groups of Wistar rats discriminated by striving for alcohol and rejecting it after the information load (alimentary instrumental conditioning in a labyrinth). The specific activities of neurotransmitter metabolizing enzymes (MAO A and B, acetylcholinesterase, and acetylcholinetransferase) and the content of biogenic amines and their metabolites (serotonin, 5-hydroxyindoleacetic acid, noradrenaline, and dopamine) were measured in homogenates and subfractions of sensorimotor cortex and caudate nucleus. It was found out that the biochemical indices correlated with cognitive abilities of animals. Stress-resistant rats, which were capable for acquisition of the complex skill, refused alcohol after the information load and were characterized by activation of the brain neurotransmitter systems. The rats, which were unable to fulfill the cognitive task, began to abuse alcohol and were characterized by suppression of the neurotransmitter systems. It seems possible that the brain neurotransmitter metabolism adequately reflects the characteristics of the higher nervous activity of animals and their resistance to alcohol.

Alcohol Drinking↗
PubMedDate not supplied

[The acquisition of a cyclic maze habit in rats (as a model of cognitive activity) with removal of the amygdaloid body].

Learning cyclic habit in a multialternative maze (with a possibility of many rewarded choices) was shown to be possible for amygdalectomized rats. All three normal types of the "learning curves" (a number of cycles as a function of the number of sessions) were observed in rats after surgery, i.e., exponent, logistic function, and "no-trend" function. This is in agreement with Simonov's concept. However, the general style of behavior was changed. The behavior became "excessive": there was an increase in the number of errors and in the locomotion rate, which suggests a disbalance of emotional-cognitive interrelations. The extent of deviation from norm is different for each type. The findings suggest the different functional weight of amygdala in the normal activity.

Amygdala↗
PubMedDate not supplied

[Response of sensorimotor cortex neurons to weak disturbances of the magnetic field in Wistar rats. Cytochemical study].

The influence of weak disturbances (up to 300 microT) of natural magnetic field on the protein metabolism in neurons of sensomotor cortex (layers III and V) in Wistar rats upon learning in a complex maze was studied. It was found that sensomotor neurons were very sensitive to weak disturbances of magnetic field. The protein content increased, while the nucleus-cytoplasm ratio and osmotic state of neurons remained unchanged. The specificity of neuron's reaction manifested itself in a sharp increase of nucleus and cytoplasm dimensions. In associative neurons (layer III), both the nucleus and cytoplasm were involved in the response; in efferent neurons (layer V), only nuclear parameters changed. The variance coefficients of all parameters of protein metabolism in sensomotor neurons, independently of their functional properties, were much higher than in control, which resulted in a wide diversity of cytochemical response.

Animals↗