ИСТИНА

Inspite of extensive research no attempts were done to select mice or rats for high scjres of cognitive tasks (namely for tasks which require the mental representation, e.g. spatial memory tasks). Laboratory mice ability to extrapolate the direction of movement of the food bait when it disappears from view behind the opaque screen and to find the food using this information was evaluated first in mice of genetically heterogenous population and then in mice specially bred for high scores of this task. The success of extrapolation task solution was scored as the percentage of correct choices during first task presentation (for the group) and as the similar percentage for 6 or 12 trials. The animals with higher scores (correct solution at the 1st trial and no less than 85% of correct solutions in sum) were used for further breeding, their progeny was tested and selected for high extrapolation scores to form the Ex strain. Another criterion for selection was the lack of anxiety behavior during extrapolation test – animals displaying short solution latencies and lack of refusals to participate the task were selected. Heterogenous population mice were randomly bred in parallel with the selected strain and served as non-selected control (Co-Ex). Mice of F1-F4 generations demonstrated no significant differences of correct solution scores from 50% chance level. At the same time the proportion of “good” solvers among mice of selected strain was significantly higher than among controls. The proportion of correct task solutions in mice of F5-F7 was significantly above the chance level – both in selected strain and in control population? No difference was found in the proportion of “good” solvers. At the same time the anxiety levels (elevated plus maze, EPM), stress-reactivity (slippery funnel test as Porsolt test analog) and exploration behavior (closed plus-maze) were different in these Ex and Co-Ex mice. Ex mice were more effitient in exploration of the close plus maze while Co-Ex mice demonstrated the elevated propensity for stereotypical and repeated arm visits together with high defecation scores. The slippery funnel test revealed significantly higher proportion of active coping reactions in Ex mice and their longer duration. The EPM anxiety score were significantly higher in Co-Ex mice. Thus the first generations of mice selection for high “cognitive ability” demonstrated yet not clear differences in the task solution scores per se, but showed the differences in anxiety levels. The hypothesis to be proved or rejected is that cognitive abilities are better revealed when animal anxiety level is nor high, but some optimal level of anxiety could be the necessary prerequisite for expression of cognitive abilities. The work was partly supported by RFBR (grant N 10-04-00891).