[Interstrain differences in the the behavior of mice selected for greater and lesser brain mass]

The capability for extrapolation of movement direction of stimuli and learning ability in T-maze were studied in F15-F18 mice generations, selected for large (LB) and small (SB) brain weight. There were no significant or stable differences between strains in capacity for extrapolation. Learning ability was higher in mice of the LB strain. In these mice, the behavioral asymmetry (the tendency to move to the right) was observed during performance of both extrapolation and T-maze tasks. Since such an asymmetry was absent in mice of initial heterogeneous population, we think that the observed phenomenon may be a concomitant result of brain weight selection. The described strains present a model for studying the functional relationships between brain weight and behavior.