INTERSTRAIN DIFFERENCES IN EXTRAPOLATION CAPACITY AND PLUS-MAZE EXPLORATION CORRELATE WITH SOME NEUROCHEMICAL CHARACTERISTICS IN MICE

C57BL/6J (B6) and CBA mice with normal karyotype and respective substr ains carrying robertsonian translocation (fusion) of chromosomes 8 and 17 (Rb) were compared in their ability to extrapolate the direction o f stimulus movement disappearing from the field of vision, rearings an d hole-poke responses, and exploration strategies in a plus-maze. Rb m ice were shown to be superior to normal karyotype groups in extrapolat ion behaviour, The pattern of interstrain differences in noradrenaline level in the cortex and serotonin turnover indices in the hippocampus correlated with differences in extrapolation ability; while explorati on strategies in the plus-maze correlated with differences in dopamine level and its turnover rate in the neocortex and striatum. The data d emonstrated that chromosomal rearrangement inducing behavioural differ ences was accompanied also by discrete neurochemical changes, and that spatial exploration strategies (being probably the constituent of gen eral spatial abilities of mice) were to a large extent independent fro m extrapolation ability which was regarded as the index of animal reas oning capacity.