Influence of "Enriched Environment" on Behavior and Neurogenesis in Mice Selected by Cognitive Trait.

Mice selected for high score in the extrapolation test (EX line) and kept under conditions of "enriched environment" for 3 months demonstrated changes in locomotor and exploratory activity and enhanced reaction to novelty. The relative brain weight was higher and neurogenesis in the hippocampal fascia dentate was more intensive in this group. In non-selected mice, the changes were similar, but insignificant in many cases.

Intermale aggression in mice, selected for the cognitive trait.

The data are presented on intermale aggression in mice which were selected for high scores of cognitive trait (the ability for extrapolation of movement direction) in comparison to the data of control mice performance. The changes in aggression level in the course of selection are presumably connected with anxiety level which also changed during selection generations.

The ability to solve elementary logic tasks in mice with the knockout of sodium-calcium exchanger gene 2 (NCX2).

Mice with a knockout of the sodium-calcium exchanger 2 (NCX2) gene were statistically significantly more successful than wild-type controls in the solution of two cognitive tasks, the test for the capacity to extrapolate the direction of the stimulus movement and the "puzzle-box" test for the capacity to find a hidden route to safe environment, which were based on food and aversive motivations, respectively. In both tests, the success of task solution was based on the animal's ability to use the object's "permanence" rule (according to J. Piaget).

[The behavior of mice selected for cognitive trait in hyponeophagia test].

Hungry mice from strain which is under selection for high scores of capacity for extrapolation the direction of stimulus movement (line EX) the hyponeophagia level (reaction to new food in novel environment) was significantly lower than in mice of control unselected population (CoEX). This signify their lower anxiety as well as higher neophilia (which in turn is connected to cognitive abilities). These mice displayed more:approaches to food, they ate food for longer time intervals and their consumed more food.